Study On Rudimentary Panicle Development In Rice

Rudimentary panicle development is very important in the rice yield. Farm experiments were conducted to study the morphologic structural transformation of embryo sac and pollen, as also the correlated biological activity, which has a significant meaning in rice production and reproductive molecular biology of rice. The main results are shown as following:(1) After twice meiotic divisions, archesporial cell, the first stage of embryo sac development, divides into quartets. Later undergoing thrice mitotic divisions it becomes 8-celled embryo sac from which the mature embryo sac develops.(2) Also begin with archesporial cell, pollen divides periclinally into primary parenchyma cell, which formed epidermis,endothecium,middle lamella and tapetum through periclinal division, and primary sporogenous cell, which formed mature pollen full of reserve materials such as starch .(3) The ratio of ear to stem rises steeply after spikelet primordium differentiation and gets greater than 0.5 when the pollen gets mature.(4) The activities of CAT,SOD,POD in anther descend gradually during pollen development stages.(5) At the meiotic division of pollen mother cell, the content of soluble sugar in anther reaches maximum value, and then descends gradually.(6) The content of soluble protein in ears gets the first peak value at the meiotic division of pollen mother cell, and then rises slightly during the formative stage of staminate and pistillate; and what in leaves gets minimum value at the meiotic division of pollen mother cell, and then rises steeply.(7) The content of IAA shows a descent in the form of"S", and the content of ZR is high at both ends and low at intermedial stages in ears during the rudimentary panicle developing.