نتایج جستجو برای: and pollen
تعداد نتایج: 16831828 فیلتر نتایج به سال:
Pollen deposition and pollen tube formation are key components of angiosperm reproduction but intraspecific variation in these has rarely been quantified. Documenting and partitioning (populations, plants and flowers) natural variation in these two aspects of plant reproduction can help uncover spatial mosaics of reproductive success and underlying causes. In this study, we assess variation in ...
Introduction Instrumental records span only a tiny fraction (<107) of the Earth’s climatic history. Therefore, indirect source of climate data must be used. Subfossil pollen and plant macrofossil data derived from sediment profiles can provide quantitative information on past climate. Recognizing the relationship between pollen assemblages and climatic variables and then interpreting foss...
Gypsophila with approximately 150 speciesrepresents the fourth largest genus of Caryophyllaceae and the second genus of tribe Caryophylleae. Iran is the second main center of Gypsophila diversity with 38 species in the world. Considering Gypsophila as one of the most polymorphic genus of the family andalmost half of its taxa distributed in Iran as endemic, thus makes it as a significant genus f...
most sweet cherry (prunus avium l.) cultivars are self-incompatible and have problems of fertilization and fruit set. to produce commercial crops they need compatible and suitable pollinizers. the compatibility of “zarde daneshkadeh”, “protiva”, “sorati lavasan”, “haj-yosefy” and “meshkin shahr” cultivars with “shoa-o-saltaneh” as seed parent studied in a randomized complete block design (r...
Intraspecific variation in pollen deposition and number of pollen tubes per style is rarely quantified, but is essential for assessing the occurrence of pollen limitation and pollen competition and their evolutionary implications. Moreover, pollen deposition, pollen tube growth, and the fate of fertilized ovules are rarely distinguished in field studies. Here we present such a study in eight na...
BACKGROUND In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect tax...
Higher “plants minimize their exposure to pollen from diverse species by precise regulation of flowering time, development of floral organs, and interactions with specific pollinators. These measures do not guarantee success, however, because of the vast quantities of pollen in the environment. Consequently, to ensure that only the appropriate sperm are delivered to the eggs, many plants have e...
Pollen ranges from 2.5% to 61% protein content. Most pollen proteins are likely to be enzymes that function during pollen tube growth and subsequent fertilization, but the vast range of protein quantity may not reflect only pollen–pistil interactions. Because numerous vertebrate and invertebrate floral visitors consume pollen for protein, protein content may influence floral host choice. Additi...
The regulation of protein collection through pollen foraging plays an important role in pollination and in the life of bee colonies that adjust their foraging to natural variation in pollen protein quality and temporal availability. Bumble bees occupy a wide range of habitats from the Nearctic to the Tropics in which they play an important role as pollinators. However, little is known about how...
Flowers of cultivated buckwheat (Fagopyrum esculentum Moench) often receive natural pollen loads of fewer than 10 pollen grains. The cultivated varieties also have high genetic variability. These observations raise the question of whether seed production in buckwheat is often limited by pollen delivery, and whether small increases in pollen load could result in gametophytic selection through po...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید