1 We examined how seed size and seedling growth rate influence recruitment success of neotropical pioneer species. We investigated the soil seed bank, and followed seedlings from emergence and establishment to the sapling stage in artificially created gaps in secondary forest on the Barro Colorado Nature Monument, Panamá. 2 To simulate microsite variation within gaps, litter addition/removal an...

A study was conducted for assessing quality of 15 hybrid rice seed samples and management of seed borne fungal pathogens by three selected chemicals namely Bavistin (0.3%), Thiovit (0.3%) and Provax (0.3%) along with two botanicals such as: Garlic extract (Allium sativum) (1:1) and Allamanda leaf extract (Allamanda cathartica) (1:1) and a bio-control agent BAU-Biofungicide @ 3% (Trichoderma bas...

Our main aim was to determine the contribution of the seed bank to vegetation regeneration following a disturbance consisting in a deep ploughing and a thorough homogenisation of a perennial grassland. In the seed bank prior to disturbance, seed distribution through the vertical soil profile was evaluated to determine the initial seed species structure. Then, several characteristics of the shal...

Agriculture can evolve independently only where intensive hunter-gatherer plant use has previously evolved, and both developments are limited by two major evolutionary constraints: climatic variability and social convention. During the Pleistocene, environmental variability constrained plant productivity and therefore plant-intensive subsistence; but during the Holocene it was the hunter-gather...

Potato has become one of the primary cash crops in the arid region of the Loess Plateau. However, what and how cereal crops to rotate with potato is better for the farmer’s income and environment is unclear now. 11 potato based rotation systems were simulated in Yulin, using EPIC model based on local information. Results showed 1) Though mean potato yield decreased from 6.84 to 5.38 t/hm, the m...

A study was initiated in 2001at four locations in western Canada to investigate an integrated approach to managing wild oat, the region’s worst weed. The study examined the effects of combining semidwarf or tall barley cultivars with normal or twice-normal barley seeding rates in either continuous barley or a barley–canola–barley–field pea–barley rotation. Herbicides were applied at 25, 50, and...

SUMMERY The water-impermeable seed coat of 'hard' seeds is commonly considered a dormancy trait. Seed smell is, however, strongly correlated with seed water content, and hard seeds are therefore olfactionally cryptic to foraging rodents. This is the rationale for the crypsis hypothesis, which proposes that the primary functions of hard seeds are to reduce seed predation and promote rodent seed ...

Seed size in higher plants is an important agronomic trait, and is also crucial for evolutionary fitness. In flowering plants, the seed comprises three major anatomical components, the embryo, the endosperm and the seed coat, each with different genetic compositions. Therefore, seed size is coordinately determined by the growth of the embryo, endosperm and maternal tissue. Recent studies have r...

Seed limitation, defined as the failure of seeds to arrive at sites favorable for recruitment, may be a critical force structuring plant communities. When seed limitation is strong, interspecific competition is reduced, and competitive exclusion may be slowed to the extent that diversity can be maintained through speciation and migration. In mature tropical forests, seed limitation may be espec...

seed loss at harvesting time is one of the factors reducing seed yield in at farms. this study was carried out within a research farm in karaj to evaluate and select a proper pinto bean line for mechanized harvesting at two moisture contents during harvesting and their effect on seed yield and yield loss among three lines of pinto bean. the experiment was split-plot based on randomized complete...