Seedling Growth

Seeds of four lettuce (Lactuca sativa L.) varieties (Romaine, Augusta, Vista and Verte) differing in their salt sensitivity were sown at 0 (Control), 50, 100 and 150 mM NaCl. The final germination percentage decreased with the increasing salinity and was annulated at the highest salt concentration in Vista and Verte, the most sensitive varieties. However, in the less sensitive ones, Romaine and Augusta, it was slightly modified at 50 and 100 mM NaCl and then decreased by 50% compared with the control, at 150 mM. The effects of NaCl 100 mM on seedling growth, phytase activities, phytate and inorganic phosphorus contents were studied in Romaine and Vista showing different behaviours towards salinity. Radicle and hypocotyl length and fresh and dry weights were reduced by salt treatment in both varieties. In addition, radicle phytase activity exhibited an increase in Romaine (less sensitive) and a decrease in Vista (more sensitive). In hypocotyl, this activity showed no difference with the control in the two varieties. However, in cotyledons, and during early hours after germination, salinity decreased phytase activity in both varieties whereas in the later hours (72-96 h) this activity reached the value of the control in Romaine. The enhancement of phytase activity was concomitant with an increase in orthophosphate content and a decrease in phytate reserve. These results suggest that salt presence in the medium delays Pi remobilization from phytate stock, but stimulates assimilation of phosphorus more than its accumulation in the organs of the two lettuce varieties.

Eleven allelochemicals (ferulic acid, cinnamic acid, 4-hydroxybenzoic acid, hydroxycinnamic acid, methyl propionate, oxalic acid, methylmalonic acid, p-anisic acid, butyric acid, 3-hydroxybutyric acid, and azulene) were identified in the exudate of Cistus ladanifer L. We studied the effect of each on germination, cotyledon emergence, root length, and cotyledon length of Rumex crispus. Three groups were distinguished with respect to phytotoxic activity: compounds with low activity (ferulic acid, 4-hydroxybenzoic acid, oxalic acid, methylmalonic acid, p-anisic acid, hydroxybutyric acid, and azulene), with intermediate activity (cinnamic acid and hydroxycinnamic acid), and with high activity (methyl propionate and butyric acid). The effect of the interaction of the compounds was studied. When acting conjointly, all combinations tested produced a more negative effect on both germination and seedling growth than when acting alone. The interaction affected cotyledon emergence and root length more negatively than germination and cotyledon length. When hydroxycinnamic acid and cinnamic acid were added to these mixtures there was an enhancement in the phytotoxic activity, accentuating the effect of the other allelochemicals.

We analyse the factors controlling seedling establishment of Scots pine at its southernmost geographical limit (southern Spain), by monitoring emergence, survival and growth for up to 4 years in the microhabitats to which seeds are dispersed. Naturally established seedlings were monitored in two mountain ranges, and experimental sowings were performed both in woodlands and in adjacent successional shrublands into which the forest could expand. 2 Emergence was high in all microhabitats, although it was highest under the canopy of shrubs. Overall survival was low, with c. 90% of seedlings dying in the first growing season (c. 98% after several growing seasons). Survival differed among microhabitats, being highest under shrubs and extremely low (or zero) under pines or in bare soil. 3 Seedling growth was the highest in areas of bare soil, intermediate under shrubs, and very low under pines. 4 Establishment under pines was prevented by both mortality and poor performance, and good performance cannot counteract high mortality in the open. Shrubs, however, acted as nurse plants, buffering summer drought without reducing radiation to levels critical for growth, and protecting seedlings from ungulate trampling, hail and frost heave. 5 Patterns of recruitment were similar for woodland stands and successional shrublands. In addition, patterns of survival for naturally established seedlings were similar to those of seedlings originating from experimental sowings. 6 Juveniles were positively associated with shrubs but negatively with bare soil or areas below pine canopies. The facilitative effect of shrubs on seedling survival therefore changes the spatial pattern of recruitment from that determined by germination. 7 Overall, processes controlling seedling establishment in these southern Scots pine forests differ sharply from those operating in its main distribution area. The comparison among contrasting geographical ranges may contribute to an understanding of the role of environmental conditions in the balance between competition and facilitation, and assist in forecasting plant regeneration responses to global climate change.

In a laboratory study, coarse and fine rice seeds were osmoprimed in fertilizer-based solutions. Priming was done in 5% aerated solution each of urea, nitrophos, DAP and SOP for 48 h. In fine rice, complete failure of germination and emergence was noted in seeds subjected to urea-based osmopriming. Electrical conductivity of seed leachates was also increased by all the seed treatments. In coarse rice, along with urea, nitrophos-based osmopriming treatments resulted in complete failure of germination and emergence. Urea and nitrophos-based osmopriming treatments also resulted in higher electrical conductivity of seed leachates than other treatments including. In both rice types, fertilizer-based osmopriming treatments resulted in lowering the germination and seedling growth.

Egamberdieva D.
Department of Biotechnology, National University of Uzbekistan, Vuzgorodok, Tashkent, 100174, Uzbekistan, e-mail: [email protected]

The action of phytohormone producing bacteria and plant growth regulators on germination and seedling growth of wheat under saline conditions were studied. Seed dormancy enforced by salinity (100 mM NaCl) was substantially alleviated and the germination was promoted by gibberelin, auxin, zeatin and ethephon from 54 to 97%. The IAA producing bacterial strains Pseudomonas aureantiaca TSAU22, Pseudomonas extremorientalis TSAU6 and Pseudomonas extremorientalis TSAU20 significantly increased seedling root growth up to 25% in non salinated conditions and up to 52% at 100mM NaCl, compared to control plants. It is concluded that growth regulators considerably alleviated salinity-induced dormancy of wheat seeds. The facts mentioned above make it possible to recommend root colonizing bacteria that produce phytohormone to alleviate salt stress of wheat grown under conditions of soil salinity.

Aqueous (10, 20, 30 and 40 g/L) and organic (hexane, chloroform and methanol, at 3000 and 6000 ppm) extracts of Inula crithmoïdes L. (roots, stems, leaves and flowers) were evaluated for their allelopathic activities on radish, lettuce, peganum and thistle. Pot cultures were conducted by incorporation of I. crithmoïdes leaves and flowers powder (1.25 and 2.5 g/kg) in soil and by irrigation with their aqueous extracts at 40 g/L. PEG (polyethylene glycol) solutions, with similar osmotic potentials of aqueous extracts, at the highest concentration, were without effect on target species, this eliminates the extracts osmotic effect. Germination index was not affected by root and stem extracts and significantly decreased by the two other ones. For growth, leaf and flower extracts had the most significant toxicity at 40 g/L, inducing up to a total inhibition. For organic extracts, a strong toxicity was recorded for the three fractions at 6000 ppm, thistle seedling growth was more sensitive, especially to chloroform fractions. Soil incorporation of residues (at 2.5 g/kg) significantly decreased root (35–100%) and shoot (0–100%) length of target species. Irrigation soil with leaves and flower aqueous extracts was harmful for peganum and thistle, respective inhibition percentages were 100% and 66.5%. I. crithmoïdes may be favorably used for incorporating in agricultural systems for sustainable weed management.► Inula crithmoïdes extracts reduced germination and growth of crops and weeds. ► Residue incorporation and irrigation with aqueous extracts were harmful for weeds. ► I. crithmoïdes had a significant allelopathic potential. ► Leaf and flower extracts were the most harmful. ► Their biomass can be incorporated into farming systems for weed management.

Survivorship and growth of seedlings of four dipterocarp species (Dipterocarpus actangulus, D. globosus, Dryobalanops aromatica, Dryobalanops lanceolata) were studied for 2.5 years in a mixed dipterocarp forest in Sarawak, East Malaysia. Predispersal seed predation rates were larger for D. globosus (75%) than D. lanceolata (27-34%) and D. aromatica (18-26%). Less than 20% of the two Dryobalanops seeds were damaged by vertebrates after seed dispersal. During the period from seed dispersal to the time when the seedlings had shed cotyledons, more dispersed seeds died in the two Dipterocarpus (ca 90%) than the two Dryobalanops (ca 60-70%). The major mortality factors during this period were uprooted and seed/seedling predation by insects or vertebrates. After the seedlings shed cotyledons, all species showed constant mortality rates of 34, 15-16, 17 and 6%/year for D. actangulus, D. lanceolata, D. aroma tica and D. globosus, respectively, in the forest understorey. Mortality was lower in less shaded conditions than in more shaded ones for D. aromatica and D. actangulus, but not significantly different for D. lanceolata and D. globosus. A majority of dead seedlings were killed by fallen branches or were found standing with wilted leaves, probably due to water stress. No significant correlation was found between seed/seedling mortality and distance from mother trees or the initial density of seeds/seedings for all species. The mean leaf production was positively correlated with the estimated diffuse light factor of their habitats for each species.

Studies on the germination characteristics of various seed groups, extent of seedling and wildling establishment, as well as measurements on early seedling growth, were conducted on Prunus africana (Hook. f.) Kalkm. (syn. Pygeum africanum Hook. f.) (Rosaceae). Germination of seeds gathered en masse (together with soil and litter) from beneath Prunus trees was significantly greater (P , 0.01) compared to those collected in pure form from the ground (with or without fruit flesh) or those picked from the trees. Treating seeds with 10 or 100 mmol gibberellic acid (GA ) showed better germination 3 23 than the control, but the difference was not statistically significant. Gibberellic acid at 1000 mmol (10 M) inhibited germination significantly (P 5 0.02). Seedlings survived better in the glasshouse (90%) than in the nursery (87%). Whereas 60% of the 280 wildlings between 2.5 and 4.0 cm successfully established, only 10% of the 220 wildlings between 8.0 and 13.0 cm survived 3 mo after these had been maintained in the glasshouse. Seedlings derived from the GA -treated seeds showed higher initial growth 3 than the control owing to rapid hypocotyl elongation. Transferring seedlings to larger pots enhanced growth significantly after a lag period of about two weeks. Seedlings maintained in the glasshouse grew better than those in the nursery (P , 0.01). The study found that germination of seeds / fruits (gathered en masse from beneath trees) on a seedbed is convenient, technically less demanding, and is cost-effective.

In order to investigate the mechanisms of maize adaptation to temperate climate, we studied photosynthetic efficiency, as evaluated by means of F PSII and chloroplast ultrastructure, as well as growth and development of two inbred lines (the chillingtolerant KW 1074 and the chilling-sensitive CM 109) under laboratory conditions. Plants were grown from seed to the 3rd leaf stage at a suboptimal temperature (14 1C/ 12 1C) and then the temperature was increased to 24 1C/22 1C. To verify the results obtained with the two model lines, twelve inbred lines were tested under both laboratory and field conditions. .pl (P. Sowiński).

Performance of seedlings of seven rain forest, canopy dominant Shorea species was studied in a transplant experiment in forest sites at three different elevations (low, mid and high) within the humid zone of southwest Sri Lanka. Five species generally inhabit low- to mid-elevations, one at mid- and lower montane elevations, and one exclusively at lower montane elevations. Temperature, rainfall and cloudiness varied with elevation. For each site seedlings were grown in pots under partial shade conditions using similar soils and evermoist conditions. All growth measures showed differences among elevation sites, among species and in the interaction between species and elevation sites. Performances of species collectively showed (i) decline in height and leaf number with increase in elevation, (ii) higher dry mass at low- and mid-elevation sites compared to that at high-elevation and (iii) a higher mass of single leaves at the mid-elevation site than at the high-elevation site. Rank ord...

Cytokinins are often considered abscisic acid (ABA) antagonists and auxins antagonists/synergists in various processes in plants. Seed enhancement (seed priming) with cytokinins is reported to increase plant salt tolerance. It was hypothesized that cytokinins could increase salt tolerance in wheat plants by interacting with other plant hormones, especially auxins and ABA. The present studies were therefore conducted to assess the effects of presowing seed treatment with varying concentrations (100, 150 and 200 mg l -1 ) of cytokinins (kinetin and benzylaminopurine (BAP)) on germination, growth, and concentrations of free endogenous auxins and ABA in two hexaploid spring wheat (Triticum aestivum L.) cultivars. The primed and non-primed seeds of MH-97 (saltintolerant) and Inqlab-91 (salt-tolerant) were sown in both Petri dishes in a growth room and in the field after treatment with 15 dS m -1 NaCl salinity. Both experiments were repeated during 2002 and 2003. Among priming agents, kinetin was effective in increasing germination rate in the salt-intolerant and early seedling growth in the salt-tolerant cultivar when compared with hydropriming under salt stress. Thus, during germination and early seedling growth, the cytokinin-priming induced effects were cultivar specific. In contrast, kinetin-priming showed a consistent promoting effect in the field and improved growth and grain yield in both cultivars under salt stress. The BAP-priming did not alleviate the inhibitory effects of salinity stress on the germination and early seedling growth in both cultivars. The increase in growth and grain yield in both cultivars was positively correlated with leaf indoleacetic acid concentration and negatively with ABA concentration under both saline and non-saline conditions. The decrease in ABA concentration in the plants raised from kinetinprimed seeds might reflect diminishing influence of salt stress. However, the possibility of involvement of other hormonal interactions is discussed.

Inoculating a soilless medium with encapsulated Trichoderma harzianum did not affect any aspect of Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn.] Franco) seed germination or subsequent growth. Results of inoculating medium with a known pathogenic isolate of Fusarium oxysporum alone, or concurrently with T. harzianum, were the same: high levels of damping-off, low amounts of hypocotyl and root disease in midsummer, and significant reductions in height growth. When seedling roots grew through T. harzianum-inoculated medium before growing into a mixture of T. harzianum-F. oxysporum-inoculated medium, mortality was reduced about 50%. Although contamination by resident Fusarium occurred, subsequent root colonization was significantly reduced in T. harzianum-amended growing medium.

A wheat seedling bioassay was used to indicate the relationship between the chemical structure of alfalfa saponins and their alMopathic activity. None of the tested saponins significantly influenced wheat germination. Seedling growth bioassays indicated significant differences among the activities of individual glycosides. The most active were medicagenic acid, its glycosides substituted at the C-3 position with glucose, and hederagenin monoglycoside. Medicageuic acid glycosides, substituted at the C-3 position with glucuronic acid, and zahnic acid tridesmoside were less active. No significant correlation was found among the aHelopathic, hemolytic, and antifungal activities of the individual glycosides.

Biofertilizers are an alternative to mineral fertilizers for increasing soil productivity and plant growth in sustainable agriculture. The objective of this study was to evaluate possible effects of three mineral fertilizers and four plant growth promoting rhizobacteria (PGPR) strains as biofertilizer on soil properties and seedling growth of barley (Hordeum vulgare ) at three different soil bulk densities, and in three harvest periods. The application treatments included the control (without bacteria inoculation and mineral fertilizers), mineral fertilizers (N, NP and P) and plant growth promoting rhizobacteria species (Bacillus licheniformis RC04, Paenibacillus polymyxa RC05, Pseudomonas putida RC06, and Bacillus OSU-142) in sterilized soil. The PGPR, fungi, seedling growth, soil pH, organic matter content, available P and mineral nitrogen were determined in soil compacted artificially to three bulk density levels (1.1, 1.25 and 1.40 Mg m (3 ) at 15, 30, and 45 days of plant harvest. The results showed that all the inoculated bacteria contributed to the amount of mineral nitrogen. Seed inoculation significantly increased the count of bacteria and fungi. Data suggest that seed inoculation of barley with PGPR strains tested increased root weight by 9 Á12.2%, and shoot weight by 29.7 Á43.3% compared with control. The N, NP and P application, however, increased root weight up to 18.2, 25.0 and 7.4% and shoot weight by 31.6, 43.4 and 26.4%, respectively. Our data show that PGPR stimulate barley growth and could be used as an alternative to chemical fertilizer. Soil compaction hampers the beneficial plant growth promoting properties of PGPR and should be avoided.

Regenerating beech stands on Ferric Podzol and Dystric Cambisol were treated with crushed dolomitic lime and ground apatite (phosphorus fertiliser) alone or in combination in a randomised block design. The lime was applied 5 years before the Pfertiliser. Seedling growth, measured as stem diameter, was not affected by the treatments. The lime significantly affected 12, and the P-treatment 5, of 13 elements analyzed for foliar concentrations. The lime increased foliar Ca and Mg concentrations and decreased those of Al, Fe, K, Mn, Na and Zn. The effect of lime on N differed between years and sites. S and B responded significantly but not consistently in relation to the lime dose. The foliar concentrations of all the elements except B could be compared with values given in the literature. Liming with dolomite increased leaf Mg to levels above the range usually found in beech. For K there is a risk of deficiency if liming is carried out where K levels are originally low. The phosphate fertiliser increased leaf P by 23-288 in the Ferric Podzol and by 5-14% in the Dystric Cambisol. In the Ferric Podzol the effect of the P-fertiliser on foliar P was not related to the lime dose, and had increased to an average of + 28% after 4 years. In the Dystric Cambisol, the P-treatment effect on foliar P was initially negatively related to the amount of lime previously applied. The average effect on foliar P in the Dystric Cambisol decreased from about + 14% in 1988 to about + 58, in 1992, and by this time no relationship between the P concentration and the lime dose remained. Crushed dolomite would efficiently correct Mg and Ca deficiencies, and ground apatite would efficiently correct P deficiencies.

Two durum wheat (Triticum durum Desf.) cultivars were tested for salt and drought tolerance at germination, seedling emergence and early seedling growth in NaCl and PEG-8000 solutions of different osmotic potentials (–0.2, –0.4, –0.6 and –0.8 MPa). Daily and final germination and emergence percentage, as well as germination and seedling emergence rate, seedling growth, fresh and dry weight were recorded under controlled conditions. Results showed that germination and emergence rates were delayed by both solutions in both cultivars, but Omrabia showed higher germination and emergence rates than BD290273 in NaCl while BD290273 was less affected by NaCl and PEG solutions at the emergence stage. Sodium chloride had a lesser effect on both cultivars in terms of germination rate, emergence rate, final germination and emergence percentage than did PEG-8000. This conclusively proves that the adverse effect of PEG-8000 on germination, emergence and early seedling growth was due to the osmoti...

Mangrove forests consist of a mosaic of tree cohorts, each having a regeneration history that depends on episodic recruitment of seedlings based on the availability of a "regeneration niche". The aim of this study was to assess seedling population structure in Ceriops tagal natural monospecific stands and one eight-year old reforested stand at Gazi Bay, Kenya, to determine performance in terms of growth and survival over a period of two years. Four natural monospecific stands (two on the western creek designated as site 1 and 2, and two on the eastern creek designated as site 4 and 5) were identified with the reforested stand (on the eastern creek) as site 3. The vegetation structure of these stands and natural regeneration were assessed by Linear Regeneration Sampling. Regeneration Class I (RCI) seedlings of known age were tagged and their growth parameters (diameter, height, leaf production and number of nodes) and survival rates monitored for a period of two years. The reforested stand had the same basal area (2.2 ± 0.1 m 2 ha -1 ) as site 1 (2.1 ± 0.1 m 2 ha -1 ), and the former's mean height was also similar to that of western creek sites (1 and 2), but lower than the eastern creek sites (4 and 5). The western creek sites had the highest seedling mortality (61 % for both) and lowest growth rates recorded over the two year period compared to a mortality of 45 % for the eastern sites. An analysis of seedling growth over the two years as a function of measured environmental factors showed a weak interaction, with height above datum (HAD) and canopy cover showing the highest correlation of only 30 %. The high mortality on the western creek sites may be attributed to harsh environmental conditions due to the limited expanse of the intertidal area of the western creek mangroves compounded with anthropogenic pressure due to its proximity to human settlements. Overall, C. tagal forests at Gazi Bay seem to be more vulnerable to environmental stress because they occur at the upper intertidal area, which limits their long-term structural development. Of the four species common at Gazi, C. tagal is the least structurally developed with very low basal areas and mean heights, which are both important determinants of wood quality. These upper-shore forests therefore require management approaches distinct from those of other species to ensure that their natural regeneration and overall structural development are not unsustainably compromised.

Patterns of genetic variation in Cordia africana, a tropical timber species, were evaluated at the population level. Bulk seed samples were collected from six natural populations in Ethiopia and examined for variations in seed morphometric traits, seed germination, and seedling growth at nursery stage. Analysis of variance revealed significant differences among provenances in all studied attributes except root collar diameter after 4 months of growth. The provenance effect, as determined by broad sense heritability, was 71–98% for seed morphometric traits, 80% for germination capacity, 42% for germination energy, 57–58% for seedling height and 3–13% for root collar diameter. Seed weight showed a significant positive correlation with altitude and negative correlation with mean annual temperature of seed origin. Germination energy was significantly correlated with longitude and mean annual rainfall. Seedling parameters and geo-climatic variables of seed origin were fairly correlated. A significant intercharacter correlation was found between seed length and seed weight, between root collar diameter at the age of 4 months and seed length and weight, as well as between seedling height after 4 and 8 months of growth. It can be concluded that the observed patterns of variation will have implications for genetic resources conservation and tree improvement.

A presoaking treatment of Shilajeet (100 ppm) and Deproteinised juice (0.1%) of Moringa leaves combined and separately was given to sterilized (with 0.1% HgCl ) seeds of bajra for 8 hours. The treated seeds were al-2 lowed to germinate in sterilized petriplates lined with moist filter paper. Data on percentage germination, seedling growth, total soluble protein and the activity of -amylase (EC, 3.2.1.1) enzyme were collected after a week of seed sowing. Results obtained during this investigation clearly indicated that moringa leaf juice with shilajeet treated seeds showed significant increase on germination and seedling growth of bajra. Increased enzyme activities were also accompanied by the enhancement of water soluble protein in shilajeet and moringa leaf juice treated seeds.

The role of Euclea divinorum in the establishment of broad-leaved thickets was investigated in Serengeti National Park, Tanzania. Thickets are declining due to frequent fires, but have not reestablished when fires have been removed. Seedlings of E. divinorum, a fire-resistant tree, were found in grassland adjacent to thickets and as thicket canopy trees and may function to facilitate thicket establishment. Seedlings of thicket species were abundant under E. divinorum canopy trees but not in the grassland, indicating that E. divinorum can facilitate forest establishment. We examined E. divinorum establishment in grassland by measuring survival and growth of seedlings with respect to fire, browsers, elephants, and competition with grass. Seedling survival was reduced by fire (50%), browsers (70%), and competition with grass (50%), but not by elephants. Seedling growth rate was negative unless both fire and browsers, or grass was removed. Establishment of thickets via E. divinorum is not occurring under the current conditions in Serengeti of frequent fires, abundant browsers, and dense grass in riparian areas. Conditions that allowed establishment may have occurred in 1890-1920s during a rinderpest epizootic, and measurements of thicket canopy trees suggest they established at that time.

Rice (Oryza sativa L.) provides about 55-80% of the total calories for people in South Asia, Southeast Asia, and Latin America. Elsewhere, it represents a high-value commodity crop. Change in the method of crop establishment from traditional manual transplantation of seedlings to direct seeding has been adopted in many Asian countries in the last two decades, in view of rising production costs, especially for labor and water. Seed invigoration is ascribed to beneficial treatments, applied to the seeds after harvest but prior to sowing, that improve germination or seedling growth or facilitate the delivery of seeds and other materials required at the time of sowing. Many seed invigoration treatments are being employed in a number of field crops, including rice, to improve seedling establishment under normal and stressful conditions. The treatments used to invigorate rice seed include hydropriming, seed hardening, on-farm priming, osmopriming, osmohardening, humidification, matripriming, priming with plant growth regulators, polyamines, ascorbate, salicylicate, ethanol, osmolytes, coating technologies, and more recently presowing dry heat treatments. In the wake of the day-to-day increasing cost of labor and shortage of water, direct seeding approaches in rice cropping systems are the subject of intensive investigation throughout the world and offer an attractive alternative to traditional rice production systems. In this regard, seed invigoration techniques are pragmatic approaches to achieving proper stand establishment in the new rice culture. They help in breaking dormancy and improving seedling density per unit area under optimal and adverse soil conditions. Induction and de novo synthesis of hydrolases, such as amylases, lipases, proteases; and antioxidants such as catalases, superoxide dismutase and peroxidases are reported to be the basis of improved performance using these techniques. The rice seed priming can be performed by soaking simply in water, a solution of salts, hormones, osmoprotectants, matric strain-producing materials, and other nonconventional means. Despite certain limitations, such as water potential, oxygen and temperature, rice seed invigoration has M. Farooq (B) 137 E. Lichtfouse (ed.), Organic Farming, Pest Control and Remediation of Soil Pollutants, Sustainable Agriculture Reviews 1, DOI 10.1007/978-1-4020-9654-9 9, C Springer Science+Business Media B.V. 2009 138 M. Farooq et al.

The treated seeds (control, KNO 3 and hydropriming) of sunflower (Helianthus annuus L.) cultivar Sanbro were evaluated at germination and seedling growth for tolerance to salt (NaCl) and drought conditions induced by PEG-6000 at the same water potentials of 0.0, −0.3, −0.6, −0.9 and −1.2 MPa. Electrical conductivity (EC) values of the NaCl solutions were 0.0, 6.5, 12.7, 18.4 and 23.5 dS m −1 , respectively. The objective of the study was to determine factors responsible for germination and early seedling growth due to salt toxicity or osmotic effect and to optimize the best priming treatment for these stress conditions.

Low-molecular-weight glutenin subunits (LMW-GS) are polymeric protein components of wheat endosperm and like all seed storage proteins, are digested to provide nutrients for the embryo during seed germination and seedling growth. Due to their structural characteristics, they exhibit features important for the technological properties of wheat flour. Their ability to form inter-molecular disulphide bonds with each other and/or with high-molecular-weight glutenin subunits (HMW-GS), is important for the formation of the glutenin polymers, which are among the biggest macromolecules present in nature, and determine the processing properties of wheat dough. Explanation of the structural basis for these correlations continues to intrigue researchers and, while earlier emphasis had been on HMW-GS, considerable attention is now being focused on the LMW-GS.

In vitro zygotic embryo culture of wild banana significantly increased the germination compared to greenhouse grown seeds. Embryo orientation and BAP concentration significantly affected germination rate. These factors together with gelling agent, dark and light conditions and coconut water, also showed variable effects on the number of roots per plant, root length, shoot length, number of days to root emergence and number of days to shoot emergence.

The aim of this study was to investigate the effect of waterlogging on morphological and physiological traits of sorghum (Sorghum bicolor L. Moench) cultivars. Four sorghum cultivars, cv. Wray, Keller, Bailey (sweet cultivar) and cv. SP1 (forage cultivar) at five expanded leaf stage were subjected to 20 days of waterlogging and drained pots were kept as the control. Twenty days of waterlogging did not cause a significant difference in shoot and root biomass among cultivars. Flooding reduced leaf area (69%), plant height (30%) and youngest leaf expansion rate of all cultivars but severely reduced in SP1 (35-80%). Flooding promoted leaf senescence of all cultivars and biomass allocation to shoot (increase in shoot/root) in Wray, Keller and Bailey, but increased biomass partitioning to root in SP1. The initiation of new nodal root was noted in SP1, whereas the ability to maintain root surface area by increase in longest root length and nodal root development near soil surface was found in Wray. Photosynthetic rate, stomatal conductance and transpiration rate were severely reduced under waterlogging conditions of sweet cultivars (65-78%), but enhanced over the control in forage cultivar (56%). The ability to conserve root surface area, allocate more biomass to shoot during waterlogging and develop root near soil surface may support new growth in Wray, whereas the ability to maintain leaf gas exchange parameters in SP1 was due to the active nodal root growth. Nevertheless, there was no relationship between photosynthetic rate and shoot growth of sorghum under anaerobic conditions.

Magneto-priming is a promising pre-sowing seed treatment to improve germinations and seedling establishment under normal or salinity stress conditions. The study aims to evaluate the effect of magneto-priming in
combination with water, proline or arginine under different salinity stress levels (324, 2000, 4000, 6000 and 8000 ppm) on germination traits, seedling growth and vigor, antioxidants enzymes activity and field performance characteristics of barley. Results indicated that magneto-priming treatments markedly enhanced all tested germination indices in comparison with control treatment (unprimed seeds) and corresponding control at various salinity stress concentrations. The improvement ranged from 1.84 to 23.24, 5.49 - 36.48 and 4.03 - 27.72% in G %, 9.65 - 27.90, 17.91- 107.69 and 14.29 - 87.91% in GI and 4.17 - 30.86, 7.13 - 41.13 and 4.96 - 30.65% in GR regarding application of magneto-priming with water, proline and arginine treatment, respectively compared to corresponding salinity level (unprimed) control. Similar enhancement was observed in MGT, where it's faster by 13.92 - 21.05, 18.60 - 26.82 and 11.88 - 22.01%, respectively. Also improvements were recorded in
seedling shoot and root length (cm), seedling dry weight (g) and seedling vigor SVII, Relative water content (RWC; %), Salt tolerance index (STI), antioxidants enzymes activity (POD, PPO and CHIA), Field emergence (FE; %) and seedling dry weight (g pot-1) compared to corresponding control. It was concluded that, application of magneto-priming treatments could scavenge or alleviate the harmful effects of salinity stress at early seedling stage and field performance of barley plants.

Nursery practice using microbial inoculants was performed to find out the efficacy of the inoculants on seed germination and seedling growth of sissoo (Dalbergia sissoo Roxb.). Microbial inoculants or effective microorganisms (EM) are a mixture of many different beneficial microorganisms in a solution. The seedlings were grown in a mixture of sandy soil and cowdung (3:1) kept in polybags with

A total of 231 different soil Streptomyces isolates were recovered from 16 different locations in North Jordan. They were assessed for their phytotoxic activity on seeds of cucumber (Cucumis sativus L.) and ryegrass (Lolium perenne L.) placed adjacent to a 2 cm wide Streptomyces culture strips grown at 28C degrees for 3 weeks on starch casein nitrate (SCN) agar. Phytotoxicity was ascertained on the basis of suppressed seed germination, discoloration of the root tip, reduced root and the shoot growth and eventual death of the root. Twenty one of the isolates exhibited adverse effect against growth of germinated cucumber seeds, germination and growth of ryegrass seeds. Using filter paper bioassay method, culture filtrate from the SCN broth of the isolate R9; identified as Streptomyces aburaviensis, significantly inhibited seed germination, radicle and shoot growth ofryegrass, reduced radicle and shoot growth of cucumber and suppressed the shoot growth of milk thistle (Silybum marianum...

Microbial Inoculants as Effective Microorganisms (EM) were applied to find out their effects on germination and seedling growth of Albizia saman in the nursery. The seedlings were grown in a mixture of sandy soils and cow dung (3:1) kept in polybags. The EM solution at different concentrations (0.1%, 0.5%, 1%, 2%, 5% and 10%) was incorporated before and after a week of sowing seeds. Germination and physical growth parameters, including shoot and root length, vigor index, collar diameter, leaf number, fresh and dry weight of shoot and root and total biomass increment over the control were measured. The nodulation status influenced by EM was also observed along with the estimation of chemical parameters like chlorophyll a, chlorophyll b and carotenoid. Both germination and the measured physical growth parameters were found significantly (P<0.05) higher in seedlings treated with different concentrations of EM solution in comparison to the control. Maximum growth was found at 2% foll...

Allelopathic effects of aqueous extract of leaves of Parthenium hysterophorus were studied on seed germination and seedling growth of three cereal crops (Oryza sativa L., Zea mays L. and Triticum aestivum L.), three cultivated crucifers (Raphanus sativus L., Brassica campestris L. and Brassica oleracea L.) and two wild species of family Asteraceae (Artemisia dubia Wall ex. Besser and Ageratina adenophora (Spreng) King and HE Robins). Seed germination of all crucifer species was completely inhibited at >2% leaf extract of Parthenium hysterophorus but in other species, except maize, complete failure of seed germination was recorded only at >6% in Triticum aestivum and Ageratina adenophora; at 10% in Oryza sativa and Artemisia dubia. Seed germination of Zea mays was not completely inhibited but it was low at high concentration of the extract. The extract had strong inhibitory effect to root elongation of seedling in cereals and to shoot elongation in crucifers and wild Asteraceae. Leaves of Parthenium hysterophorus may be a source of natural weedicide against Ageratina adenophora which will help to control invasive plants.

The allelopathic effects of fresh shoot aqueous extract of Tithonia diversifolia (Hemsl.) A. Gray was investigated on the germination of seeds and growth of young seedlings of Zea mays L. Although the fresh shoot aqueous extract did not show significant allelopathic effect on the germination of Z. mays, however, the radicle and plumule lengths of the seedlings were significantly inhibited

Con el fin de determinar si el calentamiento global podría influir en la ampliación altitudinal de hábitat en el noreste de México, se evaluó la germinación y el crecimiento de cuatro especies de plantas en un gradiente de elevación de 90 a 1960 msnm. Los individuos incluyeron tres especies nativas (Cordia boissieri, Ebenopsis ebano y Caesalpinia mexicana) y una introducida, naturalizada en la región (Melia azederach). Se pusieron a germinar en contenedores, semillas de las cuatro especies durante cuatro veces (primavera 2003, 2004; otoño 2003 y 2004), en cinco elevaciones (90, 350, 520, 1,600 y 1,960 msnm). Las tres elevaciones más bajas incluyen el rango de distribución actual de las especies, y es en éstas en donde en general se presentó la mayor germinación para todas las especies. Para C. boissieri fue en las elevaciones de 350, 520 y 1600 msnm. Para E. ebano y C. mexicana se obtuvo en 90, 350, 520 y 1600 msnm, y para M. azederach ocurrió a 90, 350, 520 msnm. Además, tanto el crecimiento de las plántulas en altura, como el número de hojas producidas, fueron en general superiores en las elevaciones con mayor porcentaje de germinación. Los resultados sugieren que las especies estudiadas tienen la capacidad para germinar y crecer por encima de su área de distribución actual.

Germination and seedling growth of Prosopis juliflora (Swartz) DC. is investigated against cadmium toxicity. Cadmium concentration
up to 400 ppm, in vitro, showed no detrimental effect on germination of abraded seeds, germination velocity was, of course impeded.
Cotyledonary area per seedling (CAS) remained more or less unaffected (r = - 0.0025, NS) but radicle growth was inhibited drastically
above 25 ppm. Compared to radicle, reduction in growth of hypocotyl was relatively of lower order. In Cd concentrations higher than
50 ppm, radicle appeared somewhat dehydrated, turned brown and almost burnt gradually in higher concentrations. TL50 values for
Hypocotyl and radicle growth were 288 and 36 ppm of Cd, respectively. Such values calculated on the basis of regression for
hypocotylar growth turned out to be 300 ppm. Radicle length related with Cd curvilinearly indicating 50 % reduction at 45.4 ppm of
cadmium.
Seedling emergence and their growth, for a period of 50 days, were also evaluated in pot containing soil contaminated with 10 –
100 mg cadmium per kg soil. Soil appeared to provide protection to the seedlings against cadmium in comparison to their, in vitro,
vulnerability to cadmium. There was delay in emergence velocity but (CAS) remained more or less unaffected up till 15th day of
growth – CAS declined at later stage. Cadmium had no significant effect on hypocotylar growth. There was delay in primary leaf
development. Fifty per cent reduction in growth of radicle, epicotyl, shoot (hypocotyl + epicotyl), number of leaves, number of leaflets
per seedling and seedling biomass corresponded with 129.5, 136, 249.8, 169.2, 104.9, and 180 mg of cadmium per kg soil,
respectively. Cadmium inhibited internodal elongation significantly. One individual each in 80 and 100 mg Cd per kg soil treatments
died after 24 days of growth. The results are discussed in eco-physiological context.

Artemisia sphaerocephala (Asteraceae) is one of the pioneer species in moving and semi-stable sand dunes in the deserts of northwest China. The outer surface of A. sphaerocephala achenes contains a pectinaceous mucilage layer that can imbibe a large amount of water when wetted. We hypothesized that the mucilage can aid achene germination in heterogeneous environments. Germination of both intact achenes and those from which the mucilage had been removed (demucilaged) declined with increasing osmotic potential and NaCl concentration. However, the germination percentage of intact achenes was significantly higher than that of demucilaged achenes. The early seedling growth of intact achenes did not differ significantly from that of demucilaged achenes in either osmotic potential or NaCl solutions. Achene mucilage presumably plays an ecologically important role in the life cycle of A. sphaerocephala by aiding germination in osmotically-and saline-stressful habitats of the cold desert environment.

Öz: Bu çalışma 2007 yılında bazı çerezlik ayçiçeği çeşit ve genotiplerinin çimlenmesi üzerine NaCl konsantrasyonlarının etkilerini belirlemek amacıyla yürütülmüştür. Araştırmada materyal olarak Opal, Beyaz, Suriye Nevadası, Elazığ, Kıbrıs, 01M007, 01M008, 01M012 ve 01M013 ayçiçeği genotipleri ve 5, 10 ve 20 dS/m NaCl konsantrasyonları ile kontrol olarak distile su (0 dS/m) kullanılmıştır. Ekimden itibaren 10. günde çimlenme yüzdesi (%), ortalama çimlenme zamanı (gün), kök uzunluğu (cm), fide uzunluğu (cm), fide yaş ağırlığı (mg) ve fide kuru ağırlığı (mg) ölçümleri yapılmıştır. Araştırma sonucunda, genotiplerin NaCl konsantrasyonlarına farklı tepkiler gösterdiği belirlenmiştir. Artan NaCl seviyeleri çimlenme yüzdesinin azalmasına, ortalama çimlenme zamanının uzamasına ve fide gelişiminin engellenmesine neden olmuştur. Beyaz genotipi tohumları, NaCl konsantrasyonlarından en az etkilenen genotip olmuştur. 10 dS/m NaCl çimlenme ve fide gelişimini engellemiştir. Çimlenmelerine rağmen beş genotipte fide gelişimi belirlenmediği için NaCl'nin fide gelişimini çimlenmeden daha fazla olumsuz şekilde etkilediği söylenebilir. Ayrıca tohumların kabuk oranının, tuz konsantrasyonlarına bakılmaksızın, su alımı ve çimlenmede önemli bir etken olduğu sonucuna varılmıştır. Kabuk oranıyla su alımı arasındaki olumlu ve önemli korelasyon (r=0.692**) bunun bir göstergesi olarak değerlendirilmiştir.

Pawpaw [Asimina triloba (L.) Dunal] is a native American fruit tree that has potential as a new fruit crop or for use in landscapes, but little information is available to nurseries on the production of containerized plants. In greenhouse experiments, growth of pawpaw seedlings in Rootrainers was examined in three fertilization regimes, two root-zone temperatures, and four substrates [ProMix, 6 pine bark: 1 sand (v/v), 1 sand: 1 sphagnum peat, and 4 pine bark: 1 sand: 1 sphagnum peat medium]. A similar germination rate of 80% was obtained in all substrates. Weekly fertigation treatments were imposed when seedlings had 2 to 3 leaves, at 0, 50, and 100 mg·L-1 N as Peters 20N-8.6P-16.6K water-soluble fertilizer plus soluble trace elements. After 140 days at the highest fertilizer rate, plant height, leaf number, and dry weight (roots, shoots, and total plant) were greater in ProMix and 1 sand:1 sphagnum peat than in 6 pine bark: 1 sand (v/v) or 4 pine bark: 1 sand: 1 sphagnum peat. Als...

The rising temperatures (>35°C) are proving detrimental to summer-sown mungbean genotypes that experience inhibition of vegetative and reproductive growth. In the present study, the mungbean plants growing hydroponically at varying temperatures of 30/20°C (control), 35/25, 40/30, and 45/35°C (as day/night 12 h/12 h) with (50 μM) or without ascorbic acid (ASC) were investigated for effects on growth, membrane damage, chlorophyll loss, leaf water status, components of oxidative stress, and antioxidants. The ASC-treated plants showed significant improvement in germination and seedling growth especially at 40/30 and 45/35°C. The damage to membranes, loss of water, decrease in cellular respiration, and chlorophyll were significantly prevented by ASC treatment to plants growing at these temperatures. The oxidative stress measured as malondialdehyde and hydrogen peroxide content was observed to be significantly lower at high temperatures with ASC application. The activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase increased at 40/30°C but decreased at 45/35°C in the absence of ASC while with its application, the activities of these enzymes were appreciably resorted. Among all the antioxidants, the endogenous ASC content decreased to the greatest extent at 45/35°C grown plants indicating its vital role in affecting the response of mungbean to heat stress. Exogenously applied ASC raised its endogenous content along with that of glutathione and proline at 45/35°C. The findings indicated that heat stress-induced inhibition in growth and chlorosis was associated with decrease in leaf water status and elevation of oxidative stress, which could partly be prevented by exogenous application of ASC. Its role in imparting protection against heat stress is discussed.

The effects of light and moisture on the early establishment of four canopy tree seedlings were studied from October 1999 to August 2000. The study was undertaken in a primary dry forest in the Hellshire Hills protected area, Jamaica with rainfall for the year totaling 650 mm most of which fell during the 6-month long rainy season. Seeds of Calyptranthes pallens, Eugenia sp., Hypelate trifolia and Metopium brownii were collected 1 month prior to the peak in the rainy season and planted in a nursery constructed within a cleared area of the forest according to a split-plot design which consisted of three blocks each containing three main treatment plots (no shading, partial shading and heavy shading) with each main plot being sub-divided into two subplots (regular watering and no watering). Seedling germination was prompt with shading having a more positive significant effect on seed germination than watering. Seedling mortality was high during the dry season particularly after the first month following a significant reduction in rainfall but seedling survival stabilised at the start of the wet season. Seedling survival was lower in un-shaded than shaded plots and in the shaded plots, survival was lower in partially shaded plots than in heavily shaded plots. Water supplement prolonged the survival of all individuals regardless of shading. Seedling size was positively affected by shading with seedlings within the partially shaded plots attaining the highest basal diameter while seedlings in the heavily shaded plots were the tallest. Water supplement also positively affected seedling size. High light levels during the wet period improved seedling growth but significantly increased seedling mortality during the dry season for all species. With respect to seedling response, M. brownii had the highest germination percentage and production but was most sensitive to drought. C. pallens had the highest survival and produced the smallest individuals. However, Eugenia sp. had the highest number of seedlings surviving at the end of the experimental period, and showed the lowest drought sensitivity. #

Most of the seed producers in Vietnam are farmers and small seed companies. They have not yet the standard storehouses to reserve seed of agricultural crops but commonly store seeds in uncontrolled temperature and moisture brick storehouses (BSH). This study identified influences of that method of seed preservation on seed quality of rice, maize and soybean seeds during storage. The results showed that seed moisture content is increased from start of storage to the eighth month and the seed quality is degraded compared to Vietnam standard of crop seed. Moisture contents of rice seed after 6 months, maize seed after 4 months and soybean after 3 months storage were higher than that of the standard seed. Seed vigor and viability were evaluated by TZ and seedling growth rate test. The degradation of vigor and viability value appeared in all three kinds of seed, but the strongest is a soybean seed degradation, from 97.0% down to 15.67% if used longitudinally cutting procedure. The TZ test method gives similar result as germination test does so that TZ test can be used to evaluate germination capacity of rice, maize and soybean seed with high accuracy. Germination percentage of three kinds of seed is reduced after 8 months in BSH. So that rice seed after 8 months, maize seed after 7 months and soybean after 4 months storage lost grade of basic seed compared to Vietnam standard for crop seed. The germination rate is different when using different tests with different substrates and methods with the same crop seeds. A large amount of fungi lives on seed surface and increases through storage months in BSH. In this study, no fungi were identified inside seeds except in soybean seed. After 8 months storage 100% of soybean seeds were infected with pathogens. Treating seeds with proper fungicides before packing and storage to protect seed and young seedling from many seedborne pathogens is necessary.

In this study, the allelopathic effect of aqueous whole mature chard plant extract (Beta vulgaris L. var. Cicla) on wheat (Triticum vulgare L. var. Sides 1) and an associated weed (chard) was investigated. Plants used were sampled in 2006, and then plant extracts were obtained after they were ground and processed with distilled water. Twenty five of wheat grains and the same number of chard seeds of uniform size and weight were placed in a mixture on sterile filter paper in 15 cm Petri-dishes. Treated Petri-dishes were each supplied with 20 ml extract of 0.25,1, 4, 8, and 12% (w/v) while untreated control was supplied with 20 ml of distilled water. After 10 days the germination percentage, vigour value, seedling growth criteria and some physiological processes were counted. The aqueous extract retarded the germination of chard more effectively than that of wheat and the effect was concentration dependent. The lowest concentration stimulated the germination of both wheat and chard; on the other hand, the germination was retarded under the application of concentrations above 1%. However, 1% concentration had a positive effect on wheat and negative on chard. HPLC analyses of the watersoluble extract of whole chard plant residue revealed the presence of eight phenolic aglycones that show the abundant of chichimec acid, (+) camphor, hydroxybenzoic, p-coumaric and vanillic acids as well as trace amounts of coumarin and protocatechuic acids. This extract may be used as a bioherbicide to control the germination and growth of itself (autotoxicity).

A field experiment was conducted in a phosphorus (P)-deficient acidic alfisol of the northwestern Himalayas using three vesicular arbuscular mycorrhizal (VAM) cultures: a local culture developed by CSK Himachal Pradesh Agricultural University, Palampur (Glomus mosseae), VAM culture from Indian Agricultural Research Institute (IARI), New Delhi (Glomus mosseae), and a culture from the Centre for Mycorrhizal Research, The Energy Research Institute (TERI), New Delhi (Glomus intraradices). These were applied alone or in combination with 25 to 75% of recommended P 2 O 5 and recommended nitrogen (N) and potassium (K) based on soil-test crop response (STCR) precision model with an absolute control, farmers' practice, and 100% of recommended P 2 O 5 dose based on the STCR model. The results revealed that sole application of either of the three VAM cultures have produced 2.68 to 9.81% and 25.06 to 28.62% greater grain yield than the control in soybean and wheat crops, respectively. Besides greater straw yield, NPK uptake as well as soil nutrient buildup increased. Increase in P fertilization from 25 to 75% of recommended P 2 O 5 dose coupled with VAM inoculation with either of the three VAM cultures resulted in consistent and significant improvement in crop productivity (grain and straw yields), NPK uptake, and improved soil nutrient status, though significantly greatest magnitude was obtained with sole application of 100% of the recommended P 2 O 5 dose. The targeted grain yields of soybean (25 q ha −1 ) and wheat (30 q ha −1 ) were achievable with 75% of recommended P 2 O 5 dose along with mycorrhizal biofertilizers, thereby indicating that application of efficient VAM fungi with 75% of recommended P 2 O 5 dose can economize the STCR precision model fertilizer P dose by about 25% without impairing crop yield targets or soil fertility in a soybean-based cropping system in an acidic alfisol.

Isolation, chemical characterization, and phytotoxicity of five new oxylipins, together with seven already known related compounds, from Cestrum parqui L He¤ rl. is reported. All the structures were elucidated on the basis of their spectral data, especially 1D-( 1 H-and 13 C-NMR, DEPT) and 2D-NMR (COSY, TOCSY, HSQC, HMBC, and NOESY). The configurations of the stereogenic C-atoms were determined by the Moshers method. The compounds have been assayed for their phytotoxicity on Lactuca sativa at concentrations ranging between 10 À 4 and 10 À 8 m. The results of the phytotoxicity tests on the germination and growth of the test species, obtained by a cluster analysis, showed interesting relationship between the chemical structures of the compounds and their biological effects.