| Precipitation in Northeast China mainly concentrated in the periods from jointing to milking of maize,the continuous rainfall often cause a periodical adversity of scant lighting and subsurface waterlogging in partings,resulting in serious loss of maize production.Therefore,it is necessary to explore maize growth and development characteristics and formation mechanism of bare plant in maize,and provide a theoretical basis of against stresses and increase maize yield in the northeast of China.Pot experiment was conducted at the horticultural station of Northeast Agricultural University in 2015-2016,The high-yielding variety Demeiya 1 and Demeiya 2 were selected as the research objects.The weak light and waterlogging stress for 10-20 days was performed at the jointing and booting stages of maize.1.Under the combeined stress of weak light and waterlogging,the leaf area of maize decreased by 29-38.5%,which was higher than that of weak light or waterlogging stress,and the chlorophyll content of maize leaves decreased by 25.3-34.5%,but it was higher than the weak light stress and was significantly lower than that under waterlogging stress.This shows that the interaction of the two kinds of adversity is obviously opposite to the effect of the two photosynthetic indexes.Demeiya 1 reduction was significantly greater than Demeiya 2,Demeiya 2 is more resistant to weak light and waterlogging stress.The effect of Waterlogging on the root function causes the leaves to be senescent in advance,the weak light treatment affects the growth rate of the blade,the mechanism of influence of the two stress is different,and all of them have an irreversible negative impact on leaf area.The weak light + waterlogging stress affect the leaf area from two aspects at the same time,and thus has a great influence.2.The weak light and waterlogging stress caused root length,root tip number and diameter decreased by 65.9%,60.4% and 6.9% in Demeiya 1respectively,67.0%,38.5% and 14.3% in Demeiya 2 respectively.Weak light and waterlogging stress caused the average bleeding of maize decreased by 65-93.7%,and waterlogging stress is the key on bleeding amount.Weak light stress has little effect on the bleeding amount.N,P accumulation were significantly affected by weak light and waterlogging stress.But the effect on potassium is smaller,.The decrease of nitrogen,phosphorus and potassium accumulation in organs affected the photosynthetic and nutrient physiological processes in the shoots,impaired the photosynthetic product accumulation and accumulation rate of plants,then affect the normal growth and development.3.The activities of CAT,SOD and POD in corn leaves decreased significantly under weak light and waterlogging stress,the MDA content is increased,the weak light treatment increased by an average of 27%,waterlogging treatment increased by an average of 13%,and the treatment of weak light and waterlogging stress increased by an average of 38%.The protective enzyme system is destroyed,and it exacerbates membrane lipid peroxidation,leading to degradation of chlorophyll and accelerated leaf senescence.4.The accumulation of dry matter in maize decreased by 37.2%-58.1% under the weak light and waterlogging treatment,more than a single stress such as weak light or waterlogging,leading to ear hypogenesis,the number of kernel and grain weight were decreased by 50.1%-68% and 22.6%-50.1%,grain yield reduction by 61.8%-75.4%.5.Maize at jointing and booting stage suffered severe weak light and waterlogging stress,it severely inhibits the growth and vitality of the root system,it inhibits the increase in the photosynthetic area and reduces the photosynthetic pigment content,limiting the vegetative growth and dry matter accumulation of maize from shoot apex and root apex two aspects,and then influence the ear development of maize,causes the deterioration and abnormality of little ear and florets,even lead to bare plant,this ultimately led to a significant reduction in production. |
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