The Staminate Cone and Male Gametophyte of Podocarpus

Male Gametophyte Development and Function

Male gametophyte development in higher plants is a complex process that requires the coordinated participation of various cell and tissue types and their associated specific gene expression patterns. The male gametophytic life cycle can be divided into a developmental phase leading to the formation of mature pollen grains, and a functional or progamic phase, beginning with the impact of the gra...

Control of male gametophyte development.

In a previous review of male gametophyte development (McCormick, 1993), it was noted that the two areas posed by Mascarenhas (1975) as fruitful areas for future research were the following. What are the differences in the two cytoplasms that determine the different cell fates of the generative and vegetative cells? And what are the functions of pollen-specific proteins? Now, 10 years later, the...

The Male Gametophyte of Flowering Plants.

the effect of planning time on the oral performance of iranian male and female efl learners بررسی تاثیر فرصت تمهید بر عملکرد گفتاری زبان آموزان با جنسیت متفاوت

چکیده برای دو دهه مطالعات بر روی فرصت تمهید و نقش آن در عملکرد گفتاری زبان آموزان نشان داده است که فرصت برای تمهید جهت انجام کار ((task عموما گفتار فراگیران را بهبود می بخشد (ellis, 2005). فرض بر این است که فرصت تمهید بار ذهنی را در خلال پردازش زبانی کاهش داده و به فراگیران اجازه میدهد تا به جنبه های مختلف زبان توجه کنند و این توجه تسهیل شده در عوض منتج به عملکرد کار موفق تر میشود. پژوهشگرا...

Male and female gametophyte development in Achillea tenuifolia (Asteraceae)

The anther, pollen and ovule development in Achillea tenuifolia were studied with a bright field microscopy. Results showed that the anther is of tetrasporangiate type and the anther wall is composed by four layers: an epidermis, an endothecium, one middle layer and a tapetum layer. Tapetum is of secretory type and its cells showed polyploidy. Pollen tetrads were tetrahedral, microspores were v...