Showing papers on "Seedling published in 2012"
TL;DR: In this article, the effects of nanoscale zinc oxide particles on plant growth and development were examined in the case of peanut seeds, and the effect of nanoscopic ZnO (25 nm mean particle size) at 1000 ppm concentration was found to promote seed germination and seedling vigor.
Abstract: An investigation was initiated to examine the effects of nanoscale zinc oxide particles on plant growth and development. In view of the widespread cultivation of peanut in India and in other parts of the globe and in view of the potential influence of zinc on its growth, this plant was chosen as the model system. Peanut seeds were separately treated with different concentrations of nanoscale zinc oxide (ZnO) and chelated bulk zinc sulfate (ZnSO4) suspensions (a common zinc supplement), respectively and the effect this treatment had on seed germination, seedling vigor, plant growth, flowering, chlorophyll content, pod yield and root growth were studied. Treatment of nanoscale ZnO (25 nm mean particle size) at 1000 ppm concentration promoted both seed germination and seedling vigor and in turn showed early establishment in soil manifested by early flowering and higher leaf chlorophyll content. These particles proved effective in increasing stem and root growth. Pod yield per plant was 34% higher compared to...
741 citations
TL;DR: The value of commonly measured seedling quality material and plant attributes defined as important in answering the question of why seedlings survive after planting are described.
Abstract: Seedling survival and successful forest restoration involves many silvicultural practices. One important aspect of a successful forest restoration program is planting quality seedlings with high survival capability. Thus the nursery needs to create seedlings with plant attributes that allow for the best chance of success once a seedling is field planted. Since the mid-twentieth century, research foresters have critically examined plant attributes that confer improved seedling survival to field site conditions. This review describes the value of commonly measured seedling quality material (i.e. shoot height, stem diameter, root mass, shoot to root ratio, drought resistance, mineral nutrient status) and performance (i.e. freezing tolerance and root growth) plant attributes defined as important in answering the question of why seedlings survive after planting. Desirable levels of these plant attributes can increase the speed with which seedlings overcome planting stress, become ‘coupled’ to the forest restoration site, thereby ensuring successful seedling establishment. Although planting seedlings with these desirable plant attributes does not guarantee high survival rates; planting seedlings with desirable plant attributes increases chances for survival after field planting.
329 citations
TL;DR: Results indicated that among the wheat germination indices, only mean germination time was affected by treatments, and Employing nanosized TiO2 in suitable concentration could promote the seed germination of wheat in comparison to bulkTiO2 but in high concentrations had inhibitory or any effect on wheat.
Abstract: The impacts of different concentrations of bulk and nanosized TiO2 on seed germination and seedling growth of wheat were studied in a randomized completely design with four replications in the College of Agriculture, Ferdowsi University of Mashhad, Iran, in 2011. The experimental treatments included five concentrations of bulk (1, 2, 10, 100, and 500 ppm), five concentrations of nanosized TiO2 (1, 2, 10, 100, and 500 ppm), and control (without any TiO2). Results indicated that among the wheat germination indices, only mean germination time was affected by treatments. The lowest and the highest mean germination time (0.89 vs. 1.35 days) were obtained in 10 ppm concentration of nanosized TiO2 and control treatments, respectively. In addition, shoot length, seedling length, and root dry matters were affected by bulk and nanosized TiO2 concentrations, significantly. Shoot and seedling lengths at 2 and 10 ppm concentrations of nanosized TiO2 were higher than those of the untreated control and bulk TiO2 at 2 and 10 ppm concentrations. Employing nanosized TiO2 in suitable concentration could promote the seed germination of wheat in comparison to bulk TiO2 but in high concentrations had inhibitory or any effect on wheat.
263 citations
TL;DR: It is hypothesize that chemical similarity between karrikins and strigolactones provided the opportunity for plants to employ a common signal transduction pathway to respond to both types of compound, while tailoring specific developmental responses to these distinct environmental signals.
Abstract: It is well known that burning of vegetation stimulates new plant growth and landscape regeneration. The discovery that char and smoke from such fires promote seed germination in many species indicates the presence of chemical stimulants. Nitrogen oxides stimulate seed germination, but their importance in post-fire germination has been questioned. Cyanohydrins have been recently identified in aqueous smoke solutions and shown to stimulate germination of some species through the slow release of cyanide. However, the most information is available for karrikins, a family of butenolides related to 3-methyl-2H-furo[2,3-c]pyran-2-one. Karrikins stimulate seed germination and influence seedling growth. They are active in species not normally associated with fire, and in Arabidopsis they require the F-box protein MAX2, which also controls responses to strigolactone hormones. We hypothesize that chemical similarity between karrikins and strigolactones provided the opportunity for plants to employ a common signal transduction pathway to respond to both types of compound, while tailoring specific developmental responses to these distinct environmental signals.
240 citations
TL;DR: The soil-less Petri dish bioassay is recommended as a rapid and simple preliminary test to identify potential toxicity of biochars on seed germination and early plant growth prior to biochar application to soil.
Abstract: Biochar can be produced from a wide range of organic sources with varying nutrient and metal concentrations. Before making irreversible applications of biochar to soil, a preliminary ecotoxicological assessment is desirable. First, we determined the effect of biochar type and rate on early growth of wheat in a soil-less Petri dish bioassay. Second, we investigated the effect of the same biochars on seed germination and early growth of wheat in ten soils with varying texture using a glasshouse bioassay. Finally, we investigated whether these biochars had similar effects on three plant species when grown in one soil. Biochar type and application rate influenced wheat seed germination and seedling growth in a similar manner in both the soil-less Petri dish and soil-based bioassay. Germination and early root growth of mung bean and subterranean clover differed from that of wheat in response to the five biochars. We recommend use of the soil-less Petri dish bioassay as a rapid and simple preliminary test to identify potential toxicity of biochars on seed germination and early plant growth prior to biochar application to soil.
227 citations
TL;DR: Irregular precipitation conditions apparently benefit Boswellia seedlings when they are mycorrhizal, with significantly higher levels of AM colonization under irregular precipitation regime than under continuous precipitation.
Abstract: Under drought conditions, arbuscular mycorrhizal (AM) fungi alter water relationships of plants and improve their resistance to drought. In a factorial greenhouse experiment, we tested the effects of the AM symbiosis and precipitation regime on the performance (growth, gas exchange, nutrient status and mycorrhizal responsiveness) of Boswellia papyrifera seedlings. A continuous precipitation regime was imitated by continuous watering of plants to field capacity every other day during 4 months, and irregular precipitation by pulsed watering of plants where watering was switched every 15 days during these 4 months, with 15 days of watering followed by 15 days without watering. There were significantly higher levels of AM colonization under irregular precipitation regime than under continuous precipitation. Mycorrhizal seedlings had higher biomass than control seedlings. Stomatal conductance and phosphorus mass fraction in shoot and root were also significantly higher for mycorrhizal seedlings. Mycorrhizal seedlings under irregular watering had the highest biomass. Both a larger leaf area and higher assimilation rates contributed to higher biomass. Under irregular watering, the water use efficiency increased in non-mycorrhizal seedlings through a reduction in transpiration, while in mycorrhizal seedlings irregular watering increased transpiration. Because assimilation rates increased even more, mycorrhizal seedlings achieved an even higher water use efficiency. Boswellia seedlings allocated almost all carbon to the storage root. Boswellia seedlings had higher mass fractions of N, P, and K in roots than in shoots. Irregular precipitation conditions apparently benefit Boswellia seedlings when they are mycorrhizal. Electronic supplementary material The online version of this article (doi:10.1007/s00442-012-2258-3) contains supplementary material, which is available to authorized users.
219 citations
TL;DR: It appears that AM formation enhanced the drought tolerance of pistachio plants, which increased host biomass and plant growth, and the accumulation of osmotic adjustment compounds, nutritional and antioxidant enzyme activity.
218 citations
TL;DR: The results suggest that seedling growth is limited by nutrients, especially K, even under highly shaded conditions in this lowland tropical forest, providing support for the multiple limiting resources hypothesis.
Abstract: Summary 1. Nutrients are a critical resource for plant growth, but the elements limiting growth in tropical forests have rarely been determined. 2. We investigated the influence of nitrogen (N), phosphorus (P), potassium (K) and micronutrients on seedling biomass and nutrient allocation in a factorial nutrient fertilization experiment in lowland tropical forest at the Barro Colorado Nature Monument, Panama. We also measured 8 years of herbivory and growth for 1800 seedlings. We sought to determine the identity of limiting elements and possible nutrient interactions. 3. The five study species were Alseis blackiana, Desmopsis panamensis, Heisteria concinna, Sorocea affinis and Tetragastris panamensis. Plants grew in deeply shaded understorey with a mean canopy openness of 4.9% (±0.7%; 1 SE). 4. Tissue N concentration increased by 11% with N addition. Tissue P concentration increased by 16% with P addition. Tissue K increased by 4% with K addition. K addition reduced root-to-shoot biomass ratio. There was no significant effect of fertilization on specific leaf area or leaf area ratio. 5. The proportion of leaves damaged and the mean level of damage by herbivory increased with P and K addition and showed a significant P · Ki nteraction. 6. Across all species and years, relative growth rate of height increased with K addition and with N and P in combination. Relative growth rate of leaf count trended 8.5% higher with K addition (P =0 .076). 7. We also added micronutrients in a parallel experiment. There was no effect of micronutrient addition on any seedling parameter. 8. Synthesis. K addition affected seedlings by enhancing tissue nutrient concentration, increasing herbivory, reducing root-to-shoot biomass ratio and increasing height growth. Additional effects of N or P on tissue chemistry, herbivory and growth offer support for the multiple limiting resources hypothesis. Our results suggest that seedling growth is limited by nutrients, especially K, even under highly shaded conditions in this lowland tropical forest.
213 citations
TL;DR: It is shown that the primary root of young Arabidopsis seedlings responds to an interorgan signal from the cotyledons and that phloem transport of photosynthesis-derived sugar into the root tip is necessary and sufficient for the regulation of root elongation growth by light.
Abstract: The most hazardous span in the life of green plants is the period after germination when the developing seedling must reach the state of autotrophy before the nutrients stored in the seed are exhausted. The need for an economically optimized utilization of limited resources in this critical period is particularly obvious in species adopting the dispersal strategy of producing a large amount of tiny seeds. The model plant Arabidopsis thaliana belongs to this category. Arabidopsis seedlings promote root development only in the light. This response to light has long been recognized and recently discussed in terms of an organ-autonomous feature of photomorphogenesis directed by the red/blue light absorbing photoreceptors phytochrome and cryptochrome and mediated by hormones such as auxin and/or gibberellin. Here we show that the primary root of young Arabidopsis seedlings responds to an interorgan signal from the cotyledons and that phloem transport of photosynthesis-derived sugar into the root tip is necessary and sufficient for the regulation of root elongation growth by light.
212 citations
TL;DR: A ecophysiological conceptual model is proposed to provide a physiological explanation of the frequent positive relationship between outplanting performance and seedling size and nutrient concentration and it considers that seedling survival in Mediterranean climates is linked to high growth capacity during the wet season.
Abstract: Reduction in size and tissue nutrient concentration is widely considered to increase seedling drought resistance in dry and oligotrophic plantation sites. However, much evidence indicates that increase in size and tissue nutrient concentration improves seedling survival in Mediterranean forest plantations. This suggests that the ecophysiological processes and functional attributes relevant for early seedling survival in Mediterranean climate must be reconsidered. We propose a ecophysiological conceptual model for seedling survival in Mediterranean-climate plantations to provide a physiological explanation of the frequent positive relationship between outplanting performance and seedling size and nutrient concentration. The model considers the physiological processes outlined in the plantation establishment model of Burdett (Can J For Res 20:415–427, 1990), but incorporates other physiological processes that drive seedling survival, such as N remobilization, carbohydrate storage and plant hydraulics. The model considers that seedling survival in Mediterranean climates is linked to high growth capacity during the wet season. The model is for container plants and is based on three main principles, (1) Mediterranean climates are not dry the entire year but usually have two seasons of contrasting water availability; (2) summer drought is the main cause of seedling mortality; in this context, deep and large roots is a key trait for avoiding lethal water stress; (3) attainment of large root systems in the dry season is promoted when seedlings have high growth during the wet season. High growth is achieved when seedlings can divert large amount of resources to support new root and shoot growth. Functional traits that confer high photosynthesis, nutrient remobilization capacity, and non-structural carbohydrate storage promote high growth. Increases in seedling size and nutrient concentration strongly affect these physiological processes. Traits that confer high drought resistance are of low value during the wet season because hinder growth capacity. We provide specific evidence to support the model and finally we discuss its implications and the factors that may alter the frequent increase in performance with increase in seedling size and tissue nutrient concentration.
167 citations
TL;DR: Germination tests appear to be a reliable procedure to differentiate between effects of different types of biochar on corn seedling growth and absorption of allelochemicals present in corn residues.
Abstract: Definition, analysis, and certification of biochar quality are crucial to the agronomic acceptance of biochar. While most biochars have a positive impact on plant growth, some may have adverse effects due to the presence of phytotoxic compounds. Conversely, some biochars may have the ability to adsorb and neutralize natural phytotoxic compounds found in soil. We evaluated the effects of biochars on seedling growth and absorption of allelochemicals present in corn ( L.) residues. Corn seeds were germinated in aqueous extracts of six biochars produced from varied feedstocks, thermochemical processes, and temperatures. Percent germination and shoot and radicle lengths were evaluated at the end of the germination period. Extracts from the six biochars had no effect on percent germination; however, extracts from three biochars produced at high conversion temperatures significantly inhibited shoot growth by an average of 16% relative to deionized (DI) water. Polycyclic aromatic hydrocarbons detected in the aqueous extracts are believed to be at least partly responsible for the reduction in seedling growth. Repeated leaching of biochars before extract preparation eliminated the negative effects on seedling growth. Biochars differ significantly in their capacity to adsorb allelochemicals present in corn residues. Germination of corn seeds in extracts of corn residue showed 94% suppression of radicle growth compared to those exposed to DI water; however, incubation of corn residue extracts with leached biochar for 24 h before initiating the germination test increased radicle length 6 to 12 times compared to the corn residue extract treatments. Germination tests appear to be a reliable procedure to differentiate between effects of different types of biochar on corn seedling growth.
TL;DR: Investigation of seed mucilage for more species in diverse habitats from the perspectives of evolution, genetics, proteomics, phylogeny and plant–microbe interactions would contribute substantially to the authors' understanding about its ecological importance.
Abstract: Studies on the ecological importance of seed coat mucilage have provided valuable information about its roles in critical stages of the plant life cycle. Seed mucilage may, by providing a moist environment and maintaining metabolic activity in the seed, promote seed development. In seed dispersal, seed mucilage influences topochory, epizoochory, endozoochory and hydrochory by anchorage of seeds to soil surface, lubrication or changing the specific weight of the seed. In arid environments, seed mucilage can prevent seeds from drying or initiate DNA repair mechanisms, thereby maintaining the soil seed bank. Seed mucilage reduces oxygen diffusion to the seed and thus has a role in regulating seed dormancy. Due to it being hydrophilous, acting as a physical barrier and containing chemicals, seed mucilage is proposed to promote seed germination in favorable environments. In seedling growth, seed mucilage may lubricate the radicle as it penetrates the soil and be degraded by soil microfloras and thus promote seedling growth. Further investigation of seed mucilage for more species in diverse habitats from the perspectives of evolution, genetics, proteomics, phylogeny and plant–microbe interactions would contribute substantially to our understanding about its ecological importance.
TL;DR: In this article, Methylotrophic bacteria were isolated from the phyllosphere of different crop plants such as sugarcane, pigeonpea, mustard, potato and radish.
Abstract: Methylotrophic bacteria were isolated from the phyllosphere of different crop plants such as sugarcane, pigeonpea, mustard, potato and radish. The methylotrophic isolates were differentiated based on growth characteristics and colony morphology on methanol supplemented ammonium mineral salts medium. Amplification of the mxaF gene helped in the identification of the methylotrophic isolates as belonging to the genus Methylobacterium. Cell-free culture filtrates of these strains enhanced seed germination of wheat (Triticum aestivum) with highest values of 98.3% observed using Methylobacterium sp. (NC4). Highest values of seedling length and vigour were recorded with Methylobacterium sp. (NC28). HPLC analysis of production by bacterial strains ranged from 1.09 to 9.89 μg ml−1 of cytokinins in the culture filtrate. Such cytokinin producing beneficial methylotrophs can be useful in developing bio-inoculants through co-inoculation of pink-pigmented facultative methylotrophs with other compatible bacterial strains, for improving plant growth and productivity, in an environment-friendly manner.
TL;DR: Fungal endophytes tested dramatically increased the percent of germination, improved EG and HTT values, and diminished wheat susceptibility to heat and drought as measured by fresh weight of seedlings when colonized by the most effective fungal endophyte.
Abstract: Seed germination is a critical life stage for plants survival and timely seedling establishment especially in stressful environments. We hypothesized that fungal endophytes would improve wheat seed...
TL;DR: Salt-tolerant genotype Lee 68 possessed the ability of higher ROS scavenging, more abundant energy supply and ethylene production, and stronger photosynthesis than salt-sensitive genotype Jackson under salt stress, which may be the major reasons why it is more salt-Tolerant than Jackson.
01 Jan 2012
TL;DR: From results it is evident that cv.
Abstract: Cadmium (Cd) is extremely toxic metal and reduces plant growth. Therefore, study was conducted to evaluate the effect of various Cd levels 0, 5, 20, 50 and 80 mg L -1 on seed germination and seedling growth of four wheat cultivars (Sehar-06, Fareed-06, Inqlab-91, Chakwal-50). Cadmium showed toxicity at 5 mg L -1 in case of root and shoot growth whereas 20 mg L -1 in case of seed germination and germination energy which is aggravated on further addition of Cd from 50 to 80 mg L -1 . Sehar-06 performed better under Cd stress while Inqlab-91 had poor performance. Later had maximum decrease in root length (70.4%), shoot length (81.2%), percent germination (68%) and germination index (76.8%) at 80 mg L -1 Cd compared to control. Tolerance index varied among different cultivars, maximum tolerance was observed in Sehar-06 followed by Fareed-06, Chakwal-50 and Inqlab-91. From these results it is evident that cv. Sehar-06 could germinate well on soils contaminated with Cd, however, more studies are required to signify its effects on growth and yield of wheat.
01 Jan 2012
TL;DR: Biologically synthesized SNPs were employed to improve the seed germination and seedling growth of Boswellia ovalifoliolata an endemic, endangered and globally threatened medicinal tree s pecies.
Abstract: The synthesis, characterization and application of biologically synthesized nanomaterials have become an important branch of nanotechnology. In this paper, we report the synth esis of highly dispersed silver nanoparticles using a dried stem b ark of Boswellia ovalifoliolata. Bark extract as the reducing agent and tested the effect on seed germination and seedling growth. Aft er exposing the silver to bark extract, rapid reduction of silv er ions was observed leading to the formation of silver nanopar ticles in the solution. UV-VIS spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at arou nd 430 nm. Scanning electron microscopy (SEM) micrograph analysis of the silver nanoparticles (SNPs) indicated that they wer e welldispersed and ranged in size 30-40 nm. Biologically synthesized SNPs were employed to improve the seed germination and seedling growth of Boswellia ovalifoliolata an endemic, endangered and globally threatened medicinal tree s pecies. Four sets of seeds were germinated on Murashige and Skoog (MS) basal medium with various concentrations (10 to 30 μg/ml) of SNPs. Higher percentage (95%) of seed germination found in treated seeds when compare to control. The control seeds (water) took longer time (10 to 20 days) to sprout, whereas all treated seeds sprouted within 10 days. The maximum height (10.6 cm) observed in seedlings treated with SNPs 4 μg/ml. The possible contribution of SNPs is to facilitate the penetrati on of water and nutrients through seed coat and accelerate the seed germination and seedling growth of Boswellia ovalifoliolata .
TL;DR: The total amount of leaf area for a given volume of substrate, rather than plants pre-conditioning in nurseries or plant age, determines seedling/sapling responses to water stress and re-watering in Mediterranean species.
TL;DR: B. bassiana was successfully established in pine seedlings using both root dip and seed coating, and the fungus was found in soil, non-sterile and sterilised samples at 2 and 4 months, but only one seedling of 30 was positive for fungus in surface sterilisation samples after 9 months.
TL;DR: This is the first report to show the protective effects of exogenous Glc against salt-induced oxidative damage in wheat seedlings associating with the evidences of ion homeostasis in cells and a better antioxidant system.
Abstract: Glucose (Glc) is an essential signaling molecule that controls plant development and gene expression, but little is known about its role in salt stress resistance on seed germination and plant growth. Here we report the effects of exogenous Glc on wheat seed germination and seedling growth under salt stress. The treatments used were 0 and 200 mM NaCl solutions supplemented with each of four Glc concentrations of 0, 0.1, 0.5 and 50 mM. The results showed that salt alone significantly inhibited seeds germination and reduced the growth of wheat seedlings. Addition of exogenous Glc in the salt solution attenuated the salt stress effects in a dose-dependent manner of Glc, as indicated by enhancement of the growth of celoeptile and radicle. Glc addition also showed significant reversal of salt stress in chlorophyll decay, water loss, dry weight, root length and accumulation of proline. The Glc-induced salt stress resistance was associated with enhanced K+ and K+/Na+ ratio in leaves, and activated antioxidant enzymes activities, thus decreasing thiobarbituric acid reactive substances (TBARS) and malondialdehyde (MDA) contents. As our knowledge this is the first report to show the protective effects of exogenous Glc against salt-induced oxidative damage in wheat seedlings associating with the evidences of ion homeostasis in cells and a better antioxidant system.
TL;DR: Paphiopedilum wardii Sumerh is an endangered tropical terrestrial orchid threatened with extinction due to over-collection and loss of suitable habitats and asymbiotic germination provides a useful way to re-establish plants in the wild (conservation) and for commercial propagation.
TL;DR: Of the three Brazilian native woody species studied, M. caesalpiniaefolia was found to have the highest Pb tolerance and phytostabilisation potential in Pb-contaminated soils.
TL;DR: Soil pH was lower in the rhizosphere than bulk soil, but was not affected by water deficiency, and water stress increased protease activity at the seedling stage, but reduced its activities at other stages compared to the control.
Abstract: Song, F., Han, X., Zhu, X. and Herbert, S. J. 2012. Response to water stress of soil enzymes and root exudates from drought and non-drought tolerant corn hybrids at different growth stages. Can. J. Soil Sci 92: 501–507. Drought tolerant corn hybrids (Zea mays L.) are an excellent model to evaluate the effect of water stress on rhizosphere functions. The purpose of this study was to investigate the influences of water stress on soil pH, enzyme activities, and root exudates from corn. Two corn hybrids, Baidan 9 (drought tolerant) and Baidan 31 (non-drought tolerant) were grown in soil-filled pots for pH and enzyme assays and in hydroponics culture for root exudate analysis. Water stress was imposed at four growth stages: seedling, elongation, tasseling and grain-filling stages. Soil pH was lower in the rhizosphere than bulk soil, but was not affected by water deficiency. Water stress increased protease activity at the seedling stage, but reduced its activities at other stages compared to the control. A sign...
Journal Article•
TL;DR: Pre sowing static magnetic field treatment of seeds can be effectively used for improving growth under water stress and lowered the antioxidant defense system of seedlings under soil water stress.
Abstract: The effect of magnetic field (MF) treatments of maize (Zea mays L.) var. Ganga Safed 2 seeds on the growth, leaf water status, photosynthesis and antioxidant enzyme system under soil water stress was investigated under greenhouse conditions. The seeds were exposed to static MFs of 100 and 200 mT for 2 and 1 h, respectively. The treated seeds were sown in sand beds for seven days and transplanted in pots that were maintained at -0.03, -0.2 and -0.4 MPa soil water potentials under greenhouse conditions. MF exposure of seeds significantly enhanced all growth parameters, compared to the control seedlings. The significant increase in root parameters in seedlings from magnetically-exposed seeds resulted in maintenance of better leaf water status in terms of increase in leaf water potential, turgor potential and relative water content. Photosynthesis, stomatal conductance and chlorophyll content increased in plants from treated seeds, compared to control under irrigated and mild stress condition. Leaves from plants of magnetically-treated seeds showed decreased levels of hydrogen peroxide and antioxidant defense system enzymes (peroxidases, catalase and superoxide dismutase) under moisture stress conditions, when compared with untreated controls. Mild stress of -0.2 MPa induced a stimulating effect on functional root parameters, especially in 200 mT treated seedlings which can be exploited profitably for rain fed conditions. Our results suggested that MF treatment (100 mT for 2 h and 200 for 1 h) of maize seeds enhanced the seedling growth, leaf water status, photosynthesis rate and lowered the antioxidant defense system of seedlings under soil water stress. Thus, pre sowing static magnetic field treatment of seeds can be effectively used for improving growth under water stress.
TL;DR: Heterotrophic seedling growth is a consequence of seed deterioration, and efforts to improve seedling germination and growth in plant breeding programs should focus on improvement of fraction of mobilized seed reserves.
Abstract: Reduced seedling growth is a consequence of seed deterioration. The heterotrophic seedling growth can be considered as the product of three components: (1) initial seed weight, (2) the fraction of seed reserves which are mobilized, and (3) the conversion efficiency of mobilized seed reserves to seedling tissues. It is not clear which of these component (s) is affected by seed deterioration. To study this subject, germination characteristics and seedling growth from deteriorated soybean (Glycine max) seeds were studied; seeds were incubated at two different temperatures of 34 oC and 40 oC for varying times. The results indicated that seed deterioration results in decreased percentage and rate of germination and decreased percentage of normal seedlings. Seedling growth and the fraction of seed reserve mobilization indicated a significant decrease with the advance of deterioration. However, the effect of seed deterioration on the conversion efficiency of mobilized reserves to seedling tissues was not significant. Thus efforts to improve seedling germination and growth in plant breeding programs should focus on improvement of fraction of mobilized seed reserves.
TL;DR: This study planted lodgepole pine or sitka alder seeds in pots containing field-collected forest soils amended with 0, 5, or 10% biochar with and without urea fertilizer and assessed for abundance and diversity of ectomycorrhizal morphotypes using light microscopy and DNA sequencing.
Abstract: Robertson, S. J., Rutherford, P. M., Lopez-Gutierrez, J. C. and Massicotte, H. B. 2012. Biochar enhances seedling growth and alters root symbioses and properties of sub-boreal forest soils. Can. J. Soil Sci. 92: 329–340. Biochar application may enhance soil properties, improve plant productivity, and increase long-term carbon storage, but impacts of biochar on plant-microbe symbioses mediating plant nutrient uptake in temperate or boreal soils are not well known. We planted lodgepole pine (Pinus contorta var. latifolia) or sitka alder (Alnus viridis ssp. sinuata) seeds in pots containing field-collected forest soils (from central British Columbia) amended with 0, 5, or 10% (dry mass basis) biochar with and without urea fertilizer (150 mg N kg−1). Pine seedlings were harvested at 4 mo and roots were assessed for abundance and diversity of ectomycorrhizal (ECM) morphotypes using light microscopy and DNA sequencing. Biochar raised soil pH, exchangeable cations and cation exchange capacity in some treatments ...
TL;DR: In this article, different heavy metal solutions were investigated for their effects on seed germination characteristics and phytoremediation potential of two oil crops ( canola, Brassica napusandsafflower, Carthamustinctorious) and a cereal crop (wheat, Triticumaestivum).
Abstract: Heavy metal pollutants are the main concern of new agricultural productions. Industrial products and using synthetic materials leads to drastically increase in concentration of different heavy metals in the environment. Lead and Cadmium are two famous heavy metals which are largely used in electronic industries thus the waste water of factories could pollute agricultural lands. Different heavy metal solutions were investigated for their effects on seed germination characteristics and phytoremediation potential of two oil crops ( canola, Brassica napusandsafflower, Carthamustinctorious) and a cereal crop (wheat, Triticumaestivum). The Canola, Safflower and Wheat seeds were germinated after treatments in solutions containing varying concentrations of heavy metals. Five different concentrations of heavy metals including (BiNO3, BiNO3, CdNO3, Sr (NO3)2, ZnNO3) at 50, 200, 350, 500, 1000 ppm and distilled water considered as control treatment. Results showed that in all treatments the percentage of seed germination, root and shoot length decreased as concentrations of solution increased. No germination was observed at 1000 ppm of cadmium level. Root and seedling vigor increased by application of 200 ppm of BiNO3. There were no seedling growth at 350 and 500 ppm of cadmium and lead concentration.
TL;DR: It is found that the combined effects of seed and establishment limitation influence recruitment; however, propagule pressure overwhelms the inhibitory effects of leaf litter thickness.
Abstract: Seedling recruitment limitations create a demographic bottleneck that largely determines the viability and structure of plant populations and communities, and pose a core restriction on the colonization of novel habitat. We use a shadetolerant, invasive grass, Microstegium vimineum, to examine the interplay between seed and establishment limitations – phenomena that together determine recruitment success but usually are investigated individually. We add increasing amounts of seed to microhabitats containing variable levels of leaf litter thickness – with reduced leaf litter simulating disturbance – to investigate whether reduced seed limitation overcomes the establishment limitation posed by litter cover. We do this across gradients in understory light, moisture and temperature, and quantify germination, survival, and then per capita adult biomass and reproduction in order to understand the implications for invasion across the landscape. We find that the combined effects of seed and establishment limitation influence recruitment; however, propagule pressure overwhelms the inhibitory effects of leaf litter thickness. Leaf litter reduces germination by 22–57% and seedling survival by 13–15% from that observed on bare soil. However, density-dependent reproduction compensates as 1–3 plants can produce far more seeds (approx. 525) than are required for persistence. As such, just a few plants may establish in understory forest habitat and subsequently overwhelm establishment barriers with copious propagule production. These results, for a widespread, invasive plant, are consistent with the emerging perspective for native plants that seed and establishment limitation jointly influence recruitment. The ability for an exotic plant species to compensate for low population densities with high per capita seed production, that then overrides establishment limitations, makes its invasive potential daunting. Further work is required to test if this is a common mechanism underlying plant invasions.
TL;DR: It is demonstrated that the tt2 mutation remarkably increased the seed FA content, decreased seed weight, and altered the FA composition, and a group of genes critical to FA biosynthesis and embryonic development are up-regulated.
Abstract: In plants, fatty acids (FAs) and FA-derived complex lipids are major carbon and energy reserves in seeds. They are essential components of cellular membranes and cellular signal or hormone molecules. Although TRANSPARENT TESTA2 (TT2) is well studied for its function in regulating proanthocyanidin biosynthesis in the seed coat, little attention has been given to its role in affecting seed FA accumulation and tolerance to environmental stresses. We demonstrate that the tt2 mutation remarkably increased the seed FA content, decreased seed weight, and altered the FA composition. The increase in FA content in the tt2 seeds was due to the relative decrease of seed coat proportion as well as the more efficient FA synthesis in the tt2 embryo. Microarray analysis revealed that tt2 mutation up-regulated a group of genes critical to FA biosynthesis and embryonic development. The mutation also altered the gene expressions that respond to stress. The microarray analysis discovered that the increase in FA accumulation of the tt2 seeds were accompanied by the significant up-regulation of FUSCA3, a transcriptional factor for embryonic development and FATTY ACID ELONGASE1, which catalyzes the elongation of FA chains. Moreover, lower seed protein accumulation during seed maturation also contributed to the increased seed FA accumulation in tt2 mutants. This study advances the understanding of the TT2 gene in seed FA accumulation and abiotic stresses during seed germination and seedling establishment.
TL;DR: This study provides evidence that large logs originating from wind uprooting or butt rot infection are most appropriate for retention to promote natural spruce regeneration in managed subalpine spruce forests.