Characteristics Of Starch Granules In Cedar Pollen And The Changes Of Starch During Germination

Pollen is the male reproductive cell of plants and plays an extremely important role in the reproductive process of plants.Starch is mainly an important nutrient in pollen.A large amount of starch is accumulated in the pollen of some species.Starch is synthesized during pollen development and degraded during pollen tube germination.The researchers found that pine pollen germinated more slowly than maize pollen and the pollen tube elongated at a slower rate.In this study,the experimental material cedar pollen and the control material maize pollen are both wind-pollinated pollens,and the starch grains stored in the two kinds of pollens are the main nutrients during pollen germination.Previous studies have shown that sugars can promote pollen tube germination,and starch is one of the most important sugars in pollen.Its characteristic difference may be one of the reasons for the difference between the speed of pollen germination and pollen tube elongation.In order to define the characteristics of starch grains in the cedar pollen and the pollen germination in the process of change,on the one hand,this study to the cedar pollen mature as the research object,the starch in contrast,the starch in maize pollen through the scanning electron microscopy(sem)and transmission electron microscopy(sem)and the measurement of indicators and one-way protein electrophoresis experiment to compare the characteristics of the two kinds of starch,This paper tries to explain one of the reasons for the slow germination of pine pollen from the characteristic difference of starch.On the other hand,the pollen of mature cedar was used as the experimental material to clarify the relevant changes of starch in the process of pollen germination through pollen germination experiment,which added new clues to the pollen tube germination process of gymnosperms.The main research results of this paper are as follows:1.The starch content in cedar pollen is low,and the expression of starch related proteins is lowThe two kinds of starch after extraction and purification were observed.The shape and size of the cedar pollen starch were different.The shape of maize pollen starch was mostly rod-like,and a small amount was round.The starch grains of cedar were smaller than that of maize pollen,and the total starch content was also lower than that of maize pollen.The amylose content of cedar pollen starch was much higher than that of maize pollen starch,and the gelatinization temperature of starch was lower than that of maize pollen.SDS-PAGE analysis of starch granulose-associated proteins showed that the surface protein and internal binding protein of cedar pollen starch were different from maize pollen starch.These results indicated that the morphology and physical and chemical properties of starch grains in cedar pollen and maize were different,and the related proteins were also different.2.The activity of pollen-related amylase in cedar was low and there were few speciesThe α-amylase activity and β-amylase activity of cedar pollen were lower than that of maize pollen by the experimental study of related amylase in pollen.Compared with starch isozyme,the activity of maize pollen isozyme was higher and the variety of enzyme was more.Western blot analysis showed that the α-amylase and β-amylase in the pollen of cedar cedar were different from those of maize.The bands and expression levels of the pollen of cedar were less than those of maize pollen,indicating that the types and activities of amylase in the pollen of cedar cedar were less than those of maize pollen.The above results indicated that the low amylase activity and fewer species in the pollen of cedar may affect the degradation of starch grains and lead to less sugar production,thus leading to slower pollen germination and slower pollen tube elongation rate.3.The starch changes during the germination of cedar pollenThis study before the cedar pollen culture found in the process of starch grains are mainly distributed in the next to the pollen wall inside the surrounding cytoplasm,along with the pollen grain slowly began to flow into the pollen tube germination as the pollen tube elongation,pollen tube into starch and the starch,the partition structure is also observed in other plant pollen tube.The indexes of pollen tubes cultured at 0 h,12 h,36 h and 72 h were determined,including starch content,soluble sugar content and amylase activity.The starch isoenzyme was also compared.The results showed that during pollen germination,total starch content decreased,soluble sugar content increased,amylase activity increased,and the types of starch isozymes increased,and the activities increased gradually.In the process of germination,the activity of related amylase is enhanced to accelerate the degradation rate of starch,thus generating more soluble sugar,which provides energy for pollen germination.