نتایج جستجو برای: and pollen grains that germinate produced short tubes

تعداد نتایج: 17066864  

2003
Claudia Erbar

In angiosperm reproduction, pollen tubes elongate from the stigma through the stylar transmitting tissue to the ovary to deliver the male gametes for fertilization. This article reviews different forms of pollen tube transmitting tracts within the style as well as possibilities for bridging the gap from the transmitting tissue to the ovule. The pollen tube transmitting tissue is the place of po...

2011
Wei Wang Li Wang Chen Chen Guangyan Xiong Xiao-Yun Tan Ke-Zhen Yang Zi-Chen Wang Yihua Zhou De Ye Li-Qun Chen

The cell wall is important for pollen tube growth, but little is known about the molecular mechanism that controls cell wall deposition in pollen tubes. Here, the functional characterization of the pollen-expressed Arabidopsis cellulose synthase-like D genes CSLD1 and CSLD4 that are required for pollen tube growth is reported. Both CSLD1 and CSLD4 are highly expressed in mature pollen grains an...

Journal: :Evolution; international journal of organic evolution 1990
Mitchell B Cruzan

The mean volume of pollen grains and total pollen production varied both within and among plants of Erythronium grandiflorum. The second flowers of two-flowered plants tended to produce smaller and fewer grains than first flowers, but there was no overall relationship between mean pollen grain size and production per flower. I evaluated the effects of pollen size differences within and among pl...

2002
David H. Firmage Amots Dafni

Many tests for pollen viability have been proposed. The ability to determine this reproductive state in the field can be very important in botanical research as well as for horticultural purposes. After reviewing a large number of tests, we compared four methods of determining pollen viability. Each of these methods can easily be carried out in the field. Viability tests were carried out on 17 ...

2015
Yunlong Lu Liqin Wei Tai Wang

The development of sperm cells (SCs) from microspores involves a set of finely regulated molecular and cellular events and the coordination of these events. The mechanisms underlying these events and their interconnections remain a major challenge. Systems analysis of genome-wide molecular networks and functional modules with high-throughput "omics" approaches is crucial for understanding the m...

2013
Yan Liang Ze-Min Tan Lei Zhu Qian-Kun Niu Jing-Jing Zhou Meng Li Li-Qun Chen Xue-Qin Zhang De Ye

Pollen tube reception involves a pollen tube-synergid interaction that controls the discharge of sperm cells into the embryo sac during plant fertilization. Despite its importance in the sexual reproduction of plants, little is known about the role of gene regulation in this process. We report here that the pollen-expressed transcription factors MYB97, MYB101 and MYB120 probably control genes w...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده زبانهای خارجی 1393

the purpose of this study was to examine the comparative effect of story retelling and role playing on efl learners’ vocabulary learning and reading comprehension. to carry out the purpose of the study 90 female learners of tabarestan language school located in noshahr were non-randomly selected. they took pet test and among these 90 participants 62 students were selected as homogenous learners...

Journal: Journal of Nuts 2014
Y. Sharafi

There is minimal information about the effect of heavy metals such as lead and copper on pollen grains and pollen tubes of fruit trees. Fruit set of these plants are affected by different environmental, biological, physical and chemical factors. If one of these factors be abnormal, pollination, fertilization and fruit set and orchard yield will decrease. In polluted cities, this phenomenon is a...

Journal: :The Plant journal : for cell and molecular biology 2009
Ke-Zhen Yang Chuan Xia Xiao-Lei Liu Xiao-Ying Dou Wei Wang Li-Qun Chen Xue-Qin Zhang Li-Fen Xie Luyan He Xuan Ma De Ye

In most flowering plant species, pollination and fertilization occur during the hot summer, so plants must have evolved a mechanism that ensures normal growth of their pollen tubes at high temperatures. Despite its importance to plant reproduction, little is known about the molecular basis of thermotolerance in pollen tubes. Here we report the identification and characterization of a novel Arab...

Journal: :The Plant cell 2009
Amy L Szumlanski Erik Nielsen

During reproduction in flowering plants, pollen grains form a tube that grows in a polarized fashion through the female tissues to eventually fertilize the egg cell. These highly polarized pollen tubes have a rapid rate of growth that is supported by a tip-focused delivery of membrane and cell wall components. To gain a better understanding of how this growth is regulated, we investigated the f...

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