Study On Morphological, Cytological And Biochemical Characteristics In Anthers Of Recessive Genetic Sterile Line Of Upland Cotton (Gossypium Hirsutum L.)

Heterosis is a common phenomenon in plant kingdom, male-sterile line has wide application in crops' cross-breeding, and it's also one of the most important methods of cross-breeding. Practice testified that cotton possessed obvious heterosis. Since there isn't an ideal triple male-sterile line in cotton at present, Recessive Genic Male-sterile Line turns into the major way of utilizing cotton's heterosis. This research was in order to announcing physiology, cytology and biochemistry mechanism of Recessive GMS in cotton, and providing theory foundation for induction and seed selection. This research adopted paraffin sections and a series of biochemistry methods, performed systematic study on mechanism of pollen abortion in three kinds of cotton Recessive GMS line (Kang A₃, Lang A and 1355A) from morphology, cytology and biochemistry. The results were as follows:1. In all of the three kinds of GMS line, sterilities compared with fertilities, flowers were smaller, filaments were shorter, anthers were smaller and dryer, and sterility anthers tightened on the lower part of stigma. The sterilities had a very significant difference in size of petal, length of filament and length of stigma overstep anther. The differences of anther quantity and pollen amount in sterilities were respectively that 1355A had an very significant difference, Kang A₃ had a significant difference, and Lang A had no significant difference. The differences of ovary size were respectively that Kang A3 had a significant difference, Lang A and 1355A had no significant difference. The differences of ovule size and quantity were respectively that Kang A₃ had no significant difference, Lang A and 1355A had significant difference. Compared with the three kinds of GMS line, the results showed that, the degeneration of Kang A₃ was fairly good, and yielding potentiality of seed was large. The degeneration of Lang A was not good, but Lang A had early-maturing character. The degeneration of 1355A was very good, and 1355A had a particular leaf shape which possessed insect-resistance, but combining ability of 1355A was fairly low. We should select them according to their own character, brought their selves preponderance into play to obtained the best utilize effect in production.2. The results of cytological observation to microspore development in the three sterilities and fertilities indicated that: PMC meiosis stage was chief abortion period of Kang A₃. The main cytological character were that PMC adhesioned mutually when took its shape; chromosome didn't take correct match, PMC propagated in bud pattern, tapetum degenerated too early or grow expand and deformity, callose precipitated, arose cytomixis in PMC meiosis stage; cytoplasm disintegrated and highly vasculized in uniucleus stage. Late uniucleus stage was chief abortion period of Lang A. The main cytological character were that, original sporogneous cells disintegrated and couldn't formed normal PMC; chromosomes separated in a jumble and cytoplasm fissioned abnormal in meiosis stage; nucleus and cytoplasm disintegrated, the exine spine couldn't be produced in uniucleus stage; nutrition cells and reproduction cells disintegrated successively in binucleus stage. Uniucleus stage was chief abortion period of 1355A.The main cytological character were that, nucleus and cytoplasm disintegrated, the thickness of cell wall increased obviously, the exine spine couldn't be produced in uniucleus stage; nutrition cells and reproduction cells disintegrated successively in binucleus stage.3. After biochemistry studied on the three sterilities and fertilities, we discovered that: Sterilities had higher contents of soluble sugar and less starch accumulation. This phenomenon indicated that transferred of soluble sugar or composed of starch was prevented, cells were in starved condition then leaded to cells degeneration and disintegrate. Sterilities had lower contents of soluble protein, and we could know that composed of protein was prevented, which caused component of protoplasm abnormal and couldn't perform normal metabolism, leaded to cells degeneration and disintegrate at last. During anther development, there were less bands of peroxidase isozymes and higher POD activity in sterilities. This indicated the difference of metabolize intensity between sterilities and fertilities, and also proved that abnormal component of peroxidase isozymes may have direct associate with abortion. Contents of MDA and electrical conductivity investigation in sterilities appeared a ascend tendency from PMC meiosis period to mature pollen period and had a similar ascend tendency, which was contents of MDA and electrical conductivity had a faster change from PMC meiosis period to binucleus stage, then tended to stable. We could infer that the key period of pollen abortion may be from PMC meiosis period to binucleus stage. Compared with these biochemical changes in the three sterilities, we could find that the emphasis point of different sterile gene which controlled various biochemical changes were different, ms₁₄ gene had significant restrain affect on transferring of soluble sugar or composing of starch, synthesizing of peroxidase isozymes, POD activity and synthesizing of MDA. ms₂ gene had significant restrain affect on synthesizing of soluble protein.