in order to study effects of competitive weeds (sinapis arvensis, hordeum spp., secale montanum and agrostemma githago) on morphological traits, yield and harvest index of winter rapeseed (brassica napus l.) cultivars a factorial experiment was conducted in islamic azad university of tabriz, during 2007-2008. experimental factors were weeds controlling times included weeding in rosette (5-7 lea...

The potential movement of transgenes from genetically modified crops to non-genetically modified crops via insect-mediated pollen dispersal has been highlighted as one of the areas of greatest concern in regards to genetically modified crops. Pollen movement depends sensitively on spatial and temporal variation in the movement of insect pollinators between crop fields. This study tested the deg...

Because the flowering and fruiting phenology of plants is sensitive to environmental cues such as temperature and moisture, climate change is likely to alter community-level patterns of reproductive phenology. Here we report a previously unreported phenomenon: experimental warming advanced flowering and fruiting phenology for species that began to flower before the peak of summer heat but delay...

Plants show phenological responses to herbivory. Some enclosure experiments have demonstrated that the onset of the peak flowering season is dependent on grazing pressure. We constructed a mathematical model using Pontryargin's maximum principle to investigate changes in flowering time by examining shifts in resource allocation from vegetative to reproductive plant components. We represented a ...

Many studies have found that the timing of flowering has shifted temporally in response to climate change, but few have ascertained the possibility of asynchrony developing between flowering and pollinator appearance. Collapses in pollination could have serious consequences for interdependent plant-pollinator networks. Five years of plant-pollinator data collected in twelve montane meadows at t...

Flowering synchrony is essential for plant reproductive success, especially in the case of small-sized populations of self-incompatible species. Closely related to synchrony, flowering intensity influences pollinator attraction and pollinator movements. Thus, a high flowering intensity may increase pollinator attraction but, at the same time, may also increase the probability of geitonogamous p...

The Mediterranean perennial herb Lobularia maritima shows an exceptionally extended flowering and fruiting that lasts for 10 months, from early September to late June. We hypothesized that such an extended phenology may be a flexible mechanism that enhances population persistence in variable Mediterranean environments, as fecundity in one part of the season could compensate for reproductive fai...

Thrips are key pests of mango, Mangifera indica (L.), in Malaysia, including the Northern Peninsular. As Penang has year-round equatorial climate and high of rainfall, the populations of thrips may be subject to variations in composition and size. With a goal of developing an appropriate control strategy, a survey was conducted in Penang to determine species composition and abundance in relati...

the experiment was carried out to study the impact of chilling and night break on the flowering of ornamental plants in their off-season period. larsenianthus careyanus (benth.) w.j. kress & mood is a wild potential ornamental ginger naturally growing in the evergreen forest of north eastern states of india was selected for the current study. the rhizomes were collected and stored at 15oc f...