The Starch Accumulaion Characteristics During The Development Of Panicum Miliaceum L. Grain

Panicum miliaceum L. have a short time growing period, strong drought and barrenresistant, good adaptability. It is one of the major crops in arid and semiarid areas in China.The grain of Panicum miliaceum L. have rich nutrients include starch, protein, fat, vitaminsand minerals, especially the starch content of grains up65%to75%. Starch use widely as rawmaterials or food additives, but there were few study on the dynamic changes of activities ofkey enzymes involved in starch synthesis of Panicum miliaceum L. grain’s development andthey relationship with starch accumulation, especially the effects of cultivation measures onPanicum miliaceum L. grain starch accumulation, there’ve still no reports. It is an importantsignificance to study the effect on dynamic accumulation of Panicum miliaceum L. starchunder different fertilization levels and different mulching cultivation, exploring themechanism of Panicum miliaceum L. grain starch accumulation and highly cultivationTechniques, and to promote farmers’ income of Panicum miliaceum L. industry developmentand production.This test combined with the Panicum miliaceum actual production, Yu Mi2as material,using field plot planting, single factor and randomized block arrangement, set differentmulching and fertilization level treatment. Four mulching treatment with straw mulching,plastic film mulching with two grooves, plastic film mulching with ridging and plastic filmmulching the whole field; Three fertilization level treatment, and a no mulching cultivationwithout fertilization as contrast test. Study the dynamic changes of starch accumulation andenzymes involved in starch synthesis during the development process of Panicum miliaceumL. grain, to explore the relationship between synthesis and enzyme activities of starch and theeffects of different cultivation mode, so as to provide theoretical basis for high yield and highquality cultivation of Panicum miliaceum L. In this paper, the main study results are as follow.The enzymes related to the grain starch synthesis, ADPG-pyrophosphorylase, solublestarch synthase, granule bound starch synthase and starch branching enzyme activities allshowed a single peak curve, the time that the peak of the enzyme activities occurs is different, ADPG-pyrophosphorylase, soluble starch synthase, granule bound starch synthase and starchbranching enzyme activities peak time is not affected by the mulching treatments. But it showdifferent in fertilization treatments, the activities peak of ADPG-pyrophosphorylase, solublestarch synthase, granule bound starch synthase and starch branching enzyme were delayedwith the high fertilization treatments. Different parts of fringe grains, the grains of lowerfringe compared to the upper fringe, the activities peak of ADPG-pyrophosphorylase, solublestarch synthase, granule bound starch synthase and starch branching enzyme appearedrelatively late, and the peak activities is smaller.In mulching cultivation, ADPG-pyrophosphorylase, soluble starch synthase, granulebound starch synthase and starch branching enzyme activities was significantly greater thancontrast test, the final grain starch accumulation and grain weight was hifher or significantlyhigher than the contrast test, and the performance of plastic film mulching with two groovesand plastic film mulching the whole field are the best. In the different fertility cultivation,ADPG-pyrophosphorylase, soluble starch synthase, granule bound starch synthase and starchbranching enzyme activities was significantly greater than contrast test in the late of fillingstage, under middle amount fertility treatment (F2), the final of grain starch accumulation andgrain weight was significantly higher than that of contrast test, lower amount of fertility (F1)and higher amount fertility (F3) treatment is not significantly. It show that the rationalfertilization can effectively improve the grain starch enzyme activities, promote grain filling,improve the yield.Under different mulching and different fertility cultivation conditions, in the process ofgrain filling of Panicum miliaceum, amylopectin accumulation rate is highly significantlycorrelated with water soluble starch synthase and starch branching enzyme activities, andsignificantly correlated with ADPG-pyrophosphorylase activities. Amylose accumulation ratewas significantly or highly significantly positive correlated with granule bound starchsynthase and ADPG-phosphorylase activity. Total starch accumulation rate was significantlyor highly significantly positive correlated with ADPG-pyrophosphorylase, soluble starchsynthase, granule bound starch and starch branching enzyme activities. The correlationbetween the rate of starch accumulation and activities of starch synthase not effected by thedifferent cultivation conditions, or effected is not significant.To sum up, the mulching and fertilition treatment can effectively improve the grainstarch enzyme activities, promote grain filling rate and increase the yield, the performance ofplastic film mulching with two grooves and plastic film mulching the whole field are the bestin mulching treatment, and the middle amount fertility(N, P2O5, K2O,6kg/666.7m2respectively) is the best in fertilition treatment. So, we should chose mulching cultivation according to the local actual conditions in Panicum miliaceum L planting process in the dryland, especially in Northern Shaanxi and the similar areas, plastic film mulching with twogrooves and plastic film mulching the whole field are the best mulching cultivation, and withreasonable fertilization measures, promote the healthy growth of Panicum miliaceum L, andto improve the synthesis and accumulation during grain filling stage, and ultimately improvethe yield.