Germination responses to light of four Neotropical forest tree species along an elevational gradient in the southern Central Andes

Seed germination is a key part of plants' life cycle and is mostly affected by the genetic background, the environmental conditions experienced by the mother plant and the seedbed conditions. The germination response to light is essential to optimize germination and seedling establishment in space and time. In addition, the germination response to light is a trait often related to the response of the seeds to their position in the soil (uncovered/buried). Here, we studied the germination response to light of four key tree species of the Yungas forest (Anadenanthera colubrina, Enterolobium contortisiliquum, Jacaranda mimosifolia and Handroanthus impetiginosus) sampled along an elevational and environmental gradient with contrasting vegetation cover and disturbance. Relative light germination (RLG) and mean germination time (MGT) were determined. Final germination was tested under cycles of light (8 h) and darkness (16 h) versus complete darkness (24 h) and elevation, and MGT was tested as a function of elevation of the provenance. The RLG increased from smaller to larger-seeded species. The MGT of three of the studied species was affected by the elevation of the provenance. Complete darkness negatively affected final germination, while two species exhibited a significant interaction between the provenance and light. The variable germination responses to light along the elevational gradient highlights the influence of the environment on germination as a key factor that should be considered for forest management, conservation and restoration projects

Differential Effects of Increasing Salinity on Germination and Seedling Growth of Native and Exotic Invasive Cordgrasses

Soil salinity is a key environmental factor influencing germination and seedling establishment in salt marshes. Global warming and sea level rise are changing estuarine salinity, and may modify the colonization ability of halophytes. We evaluated the effects of increasing salinity on germination and seedling growth of native Spartina maritima and invasive S. densiflora from wetlands of the Odiel-Tinto Estuary. Responses were assessed following salinity exposure from fresh water to hypersaline conditions and germination recovery of non-germinated seeds when transferred to fresh water. The germination of both species was inhibited and delayed at high salinities, while pre-exposure to salinity accelerated the speed of germination in recovery assays compared to non-pre-exposed seeds. S. densiflora was more tolerant of salinity at germination than S. maritima. S. densiflora was able to germinate at hypersalinity and its germination percentage decreased at higher salinities compared to S. maritima. In contrast, S. maritima showed higher salinity tolerance in relation to seedling growth. Contrasting results were observed with differences in the tidal elevation of populations. Our results suggest S. maritima is a specialist species with respect to salinity, while S. densiflora is a generalist capable of germination of growth under suboptimal conditions. Invasive S. densiflora has greater capacity than native S. maritima to establish from seed with continued climate change and sea level rise.Ministerio de Educación, Cultura y Deporte (FPU14/06556

Effects of Nanosilica Powder from Rice Hull Ash on Seed Germination of Tomato (Lycopersicon esculentum)

open5noNanosilica powders were synthesized from rice hull ash (RHA) and their effects on seed germination of tomato plants were investigated. Synthesized nanosilica powder was subjected to various characterization studies for identification of the size, structure, morphology and elemental composition. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) results showed that the nanoparticles were in agglomerated form with an average diameter of 46.5 nm and 40 nm, respectively. X-ray diffractometry (XRD) indicated that nanosilica powder is amorphous in nature. The nanosilica powder was also characterized as having a purity of 98.33% using EDXRF spectroscopy and having a surface area 172.19 m2 g-1 using the Brunauer-Emmett-Teller (BET) method. The study showed that nanosilica powder significantly improved germination parameters such as germination percentage, germination index, vigor index, mean germination time and average shoot length of tomato but not fresh weight and dry weight. The best results were found at 5gL-1 nanosilica powder. The increase over untreated control seeds was 22% for germination percentage, 47% for germination index, 92% for vigor index and 55% for average shoot length with the addition of 5 gL-1 nanosilica powder. Nanosilica powder-mediated improvement of seed germination in tomato suggests a potential application of nanosilica powder in seed germination of the plant. The study can serve as theoretical basis for further agricultural applications of nanosilica powder.openMaria Morissa Lu, Diana Marie De Silva, Engelbert Peralta, Alvin . Fajardo, Milagros PeraltaMaria Morissa, Lu; DE SILVA, DIANA MARIE; Engelbert, Peralta; Fajardo, Alvin.; Milagros, Peralt

Germination of primed seed under NaCl stress in wheat.

Copyright © 2012 Michael P. Fuller et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Soil salinity affects a large and increasing amount of arable land worldwide, and genetic and agronomic solutions to increasing salt tolerance are urgently needed. Experiments were conducted to improve wheat seed performance under salinity stress conditions after priming. An experiment was conducted using a completely randomized design of four replications for germination indices in wheat (Triticum aestivum L. cv. Caxton). Normal and primed seed with PEG6000 at −1MPa and five concentrations of NaCl (0, 50, 100, 150, and 200mM) were tested. Results indicate that priming seed significantly (P < 0.05) increased germination percentage at first count and final count, coefficient of velocity of germination, germination rate index, and mean germination time, while increasing of NaCl concentration significantly reduced it. Priming seed improved germination attributes at all NaCl concentration levels. The priming appeared to be able to overcome the effect of salt stress at 50 to 100mMand reduce the effect of NaCl at higher concentrations up to 200 mM. The primed seed gave both faster germination and led to higher germination when under salt stress. We conclude that using priming techniques can effectively enhance the germination seed under saline condition

Relationship between seed harvesting method and seed physiological quality for a number of Pioneer maize hybrids

The seed germination and seed vigor of eight Pioneer Hi-Bred maize hybrids were evaluated immediately after harvesting and a year later. The aim was to determine whether the seed showed loss of germination and vigor when shelled mechanically. The seed was cleaned but not dressed, and then germinated according to the ISTA standard procedure in four seed analysis laboratories. In addition, the seed of two randomly chosen hybrids was divided into four fractions based on size and shape, and the germination of each fraction was examined separately. All the germination results were acceptable according to the ISTA (2010) standard (over 90%), but a higher germination percentage was observed after manual shelling than after mechanical shelling. The number of abnormal seedlings, however, was higher for mechanically shelled seeds than for those harvested as whole ears. When the seed of separate seed fractions was tested, the germination percentage was lowest for the medium-sized round fraction and highest for the large flat fraction. The seed vigor of three of the hybrids was highest when maize seeds were harvested shelled rather than on the ear. For all the hybrids the germination percentage was lower for both groups when analyzed a year after harvesting. Better germination results were obtained for all the hybrids after whole ear harvesting than in the shelled group, but the difference was not significant. In the vigor tests the results obtained for mechanically shelled seed were superior to those for whole ear harvesting for the same three hybrids, but again the difference was not significant. The experiments should be repeated over several years to determine whether mechanically shelling maize seed negatively affects seed germination and vigor

Circular 91

Plants of Begonia x tuberhybrida ‘Nonstop’, ‘Clips’, and ‘Musical’ were exposed to 1, 2, 3, or 4 weeks of short days (SD, 9 hours day length) initiated at 3 stages of plant development (immediately upon germination, 4 or 8 weeks after germination). Prior to and succeeding short days, plants were exposed to long days (LD, 16 hours day length). Musical flowered on average 68 days, Clips 78 days and Nonstop 83 days after germination under continuous LD conditions. In Nonstop, SD for 1, 2, 3, or 4 weeks delayed plant development by an average 12 days compared to LD grown plants. One, 2, or 3 weeks of SD resulted in 1 week slower flowering and 4 weeks of SD resulted in 2 weeks later flowering in Clips. The sensitivity to SD varied with plant stage in Musical. Three or 4 weeks of SD initiated at germination or 4 weeks after germination resulted in an average delayed flowering of 13 days compared to LD plants. SD initiated 8 weeks after germination had no effect on rate of development in Musical

DOF AFFECTING GERMINATION 2 is a positive regulator of light-mediated seed germination and is repressed by DOF AFFECTING GERMINATION 1

Abstract BACKGROUND: The transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a repressor of the light-mediated seed germination process. DAG1 acts downstream PHYTOCHROME INTERACTING FACTOR3-LIKE 5 (PIL5), the master repressor, and negatively regulates gibberellin biosynthesis by directly repressing the biosynthetic gene AtGA3ox1. The Dof protein DOF AFFECTING GERMINATION (DAG2) shares a high degree of aminoacidic identity with DAG1. While DAG1 inactivation considerably increases the germination capability of seeds, the dag2 mutant has seeds with a germination potential substantially lower than the wild-type, indicating that these factors may play opposite roles in seed germination. RESULTS: We show here that DAG2 expression is positively regulated by environmental factors triggering germination, whereas its expression is repressed by PIL5 and DAG1; by Chromatin Immuno Precipitation (ChIP) analysis we prove that DAG1 directly regulates DAG2. In addition, we show that Red light significantly reduces germination of dag2 mutant seeds. CONCLUSIONS: In agreement with the seed germination phenotype of the dag2 mutant previously published, the present data prove that DAG2 is a positive regulator of the light-mediated seed germination process, and particularly reveal that this protein plays its main role downstream of PIL5 and DAG1 in the phytochrome B (phyB)-mediated pathway

The Bacillus cereus GerN and GerT protein homologs have distinct roles in spore germination and outgrowth, respectively

The GerT protein of Bacillus cereus shares 74% amino acid identity with its homolog GerN. The latter is a Na+/H+-K+ 19 antiporter that is required for normal spore germination in inosine. The germination properties of single and double mutants of B. cereus ATCC10876 reveal that unlike GerN, which is required for all germination responses that involve the GerI germinant receptor, the GerT protein does not have a significant role in germination, although it is required for the residual GerI-mediated inosine germination response of a gerN mutant. In contrast, GerT has a significant role in outgrowth; gerT mutant spores do not outgrow efficiently under alkaline conditions, and outgrow more slowly than wild type in the presence of high NaCl concentrations. The GerT protein in B. cereus therefore contributes to the success of spore outgrowth from the germinated state during alkaline or Na+ stress

Effect of thermal shock and ruminal incubation on seed germination in Helianthemum apenninum L. Mill (Cistaceae)

Effect of thermal shock and ruminal incubation on seed germination in Helianthemum apenninum (L.) Mill. (Cistaceae). Here, we analyse the effect of different treatments on seed germination in Helianthemum apenninum (L.) Mill. (Cistaceae), considering scarification with sandpaper, thermal shock simulating the heat from fire, and incubation in the rumen of sheep and goat simulating passage through the gut of ruminants. Mechanical scarification boosted the germination (95% vs. 6% of control treatment), indicating that the seeds have a potentially high germination rate if the coat is eroded. Thermal shock did not improve germination. Incubation in rumen increased seed germination, up to a 32% after 48h in ruminal liquid versus 12% for control seeds in the case of sheep. The results suggest that germination in H. apenninum, while not enhanced by heat from fires, may be enhanced by herbivore ingestion

Germination: a means to improve the functionality of oat

The biochemical and physiological reactions of germination have long been utilised to produce barley malt for brewing and other purposes. Also some oat malt has been produced as raw-material of ale and stout production. The main goals of malting have been the degradation of grain storage components to soften the kernel structure, synthesis of amylolytic enzymes and production of nutrients for brewing yeast. Also flavour and colour attributes have been important. During the recent years interest has arisen also in the secondary metabolites produced during germination, which can have valuable health promoting properties and act as bioactive or functional compounds in foods. By using a tailored germination/malting process a desired combination of valuable properties may be obtained in germinating grains or seeds. All this requires knowledge and know-how of the germination process and the biochemistry behind it. This paper reviews the scientific knowledge about germination/malting of oat with special emphasis on changes in grain characteristics