نتایج جستجو برای: pollen supply
تعداد نتایج: 178918 فیلتر نتایج به سال:
Almost all bees collect nectar and pollen from flowers. Female bees collect pollen to provision their nest cells, whereas they use nectar for individual energy supply and nest cell provisioning. Bees fine-tune nectar foraging to the amount and to the concentration of nectar, but the individual bees' response to variability of amount and concentration of pollen reward has not yet been studied th...
It is possible to obtain pollen germination and pollen tube growth in vitro if boric acid is present. In this work the effect was studied using as a semiquantitative parameter the mean length (J) o f Lilium longißorum pollen tubes. Pollen tube growth was examinated in depend ence on boric acid, ortho-silicic acid, nucleic bases, Ca2+ and Zn2+ in 10% sucrose solution. The maximum o f 7is obtain...
A genomic clone and the corresponding cDNA of a new Arabidopsis monosaccharide transporter AtSTP9 were isolated. Transport analysis of the expressed protein in yeast showed that AtSTP9 is an energy-dependent, uncoupler-sensitive, high-affinity monosaccharide transporter with a K(m) for glucose in the micromolar range. In contrast to all previously characterized monosaccharide transporters, AtST...
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Black gram plants subjected to varying levels of Zn supply (0.01 to 10 microM Zn) showed optimum growth and dry matter yield in plants receiving 1 microM Zn. The dry matter yield of plants decreased in plants receiving 0.01 and 0.1 microM Zn (deficient) and excess levels of Zn (2 and 10 microM Zn). The plants grown with Zn deficient supply showed delayed flowering, premature bud abscission, red...
In some plants, pollen grains accumulate storage lipids that serve as energy supply during germination. Here, three enzymes involved in early steps of oil body mobilization in the male gametophyte were functionally characterized for the first time. The effect of extracellular sugars on pollen performance and oil body dynamics was also analysed. Olive pollen oil bodies showed phospholipase A, li...
Pollen, an extremely reduced bicellular or tricellular male reproductive structure of flowering plants, serves as a model for numerous studies covering wide range of developmental and physiological processes. The pollen development represents a fragile and vital phase of plant ontogenesis and pollen was among the first singular plant tissues thoroughly characterized at the transcriptomic level ...
In flowering plants, the tapetum, the innermost layer of the anther, provides both nutrient and lipid components to developing microspores, pollen grains, and the pollen coat. Though the programmed cell death of the tapetum is one of the most critical and sensitive steps for fertility and is affected by various environmental stresses, its regulatory mechanisms remain mostly unknown. Here we sho...
In view of the ongoing pollinator decline, the role of nutrition in bee health has received increasing attention. Bees obtain fat, carbohydrates and protein from pollen and nectar. As both excessive and deficient amounts of these macronutrients are detrimental, bees would benefit from assessing food quality to guarantee an optimal nutrient supply. While bees can detect sucrose and use it to ass...
The study was conducted in the years 2004 – 2005 using two populations of Adonis vernalis L. occurring in the Adonido-Brachypodietum pinnati community at Pliszczyn near Lublin and in the Brachypodio-Teucrietum community at Stawska Góra near Che3m. The blooming of A. vernalis in the Lublin region occurs from the first days of April to the end of May. The species is characterized by an early, day...
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