background:  stresses such as heat shock, starvation, or osmotic is essential to lead isolated microspores towards embryogenesis. despite the effectiveness of stresses in embryogenesis, they exert adverse effects on metabolism and growth of the regenerated plants.objectives: the effects of heat shock and 2,4-d treatment on total protein content of treated microspores, morphological and physiolo...

During microsporogenesis, the microsporocyte (or microspore) plasma membrane plays multiple roles in pollen wall development, including callose secretion, primexine deposition, and exine pattern determination. However, plasma membrane proteins that participate in these processes are still not well known. Here, we report that a new gene, RUPTURED POLLEN GRAIN1 (RPG1), encodes a plasma membrane p...

The formation of mature and fertile pollen grains, taking place inside the anther, depends on supply of assimilates, in the form of sucrose, provided mainly by the leaves. Data is limited, however, with respect to the understanding of sucrose metabolism in microspores and the supporting tissues. The aims of the present work were to 1) follow the changes in total and relative concentrations of s...

Background:  Stresses such as heat shock, starvation, or osmotic is essential to lead isolated microspores towards embryogenesis. Despite the effectiveness of stresses in embryogenesis, they exert adverse effects on metabolism and growth of the regenerated plants. Objectives: The effects of heat shock and 2,4-D treatment on total protein content of treated microspores, morphological and physiol...

BACKGROUND AND AIMS Dioecism characterizes many crop species of economic value, including kiwifruit (Actinidia deliciosa). Kiwifruit male sterility occurs at the microspore stage. The cell walls of the microspores and the pollen of the male-sterile and male-fertile flowers, respectively, differ in glucose and galactose levels. In numerous plants, pollen formation involves normal functioning and...

Metabolic engineering was used to disrupt glutamine metabolism in microspores in order to block pollen development. We used a dominant-negative mutant (DNM) approach of cytosolic glutamine synthetase (GS1) gene under the microspore-specific promoter NTM19 to block glutamine synthesis in developing pollen grains. We observed partial male sterility in primary transgenic plants by using light micr...

The highly resistant biopolymer, sporopollenin, gives the outer wall (exine) of spores and pollen grains their unparalleled strength, shielding these structures from terrestrial stresses. Despite a limited understanding of the composition of sporopollenin, it appears that the synthesis of sporopollenin occurs in the tapetum and requires the transport of one or more sporopollenin constituents to...

Pollen grains are encased by a multilayered, multifunctional wall. The sporopollenin and pollen coat constituents of the outer pollen wall (exine) are contributed by surrounding sporophytic tapetal cells. Because the biosynthesis and development of the exine occurs in the innermost cell layers of the anther, direct observations of this process are difficult. The objective of this study was to i...

Calcium is widely known to have a role as a signaling molecule in many different processes, including stress response and activation of the embryogenic program. However, there are no direct clues about calcium levels during microspore embryogenesis, an experimental process that combines a developmental switch toward embryogenesis and the simultaneous application of different stressing factors. ...

A method for the preparation of developmentally staged microspores and young pollen from maize (Zea mays) has been devised. The preparations are of sufficient purity and quantity for biochemical analysis, including the analysis of steady-state protein and RNA populations associated with each stage. A major transition in protein populations occurs during the developmental period that encompasses...