Research On Effects Of Waterlogging Stress On Rice Growth At Critical Growing Stage And Its Application

In the river network area of the Lixiahe Plain,heavy rainfall occurs frequently in summer,and rice fields are susceptible to flood disasters,which restricts the stable production of rice crops.In order to investigate the effects of waterlogging stress on rice growth and yield,the threshold value of rice flooding tolerance and flooding tolerance time was sought,and the technical indicators of water storage lanagement after rice rain were put forward to improve the utilization rate of rainwater resources,a potted simulation test was conducted from 2016 to 2018.The experiment selected Yangjing 113 and Yangjing 4227 as the tested varieties,simulated rice flooding in the tillering,jointing,booting and milking stages,and set different combinations of flooding depth and flooding time.Focus on the effects of flooding treatment on the morphological characteristics,related physiological indicators,yield and yield components of key rice growing seasons.The main research results are as follows:(1)The effects of waterlogging stress on rice morphological indexes were studied by analyzing the changes of rice leaf length,leaf width,leaf area,plant height and internode length The resuits showed that the flooding stress increased with short duration and was normalized with flooding.Compared with the rice plants,the growth rate of plant height increased during the treatment period,and the growth rate of plant height and internode length decreased after flooding treatment,and the final performance is that the plant height of mature rice becomes shorter as the intemode length becomes shorter.In the early stage of tillering and in the middle and late stages of tillering,as the depth of flooding deepened and the flooding time prolonged,the length of panicles decreased,and the effect of flooding at jointing stage on panicle length was small.The leaf area and high-efficiency leaf area of the inverted 1 leaf,the inverted 2 leaf and the inverted 3 leaf of rice treated with full flooding for 1 day(1/1-1d)in the middle and late tillering were increased compared with the control.(2)The effects of waterlogging stress on rice physiological indexes were studied by analyzing the changes of relative chlorophyll content,net photosynthetic rate and relative conductivity of rice.The results showed that the next day after flooding treatment,the number of flooding days was small(such as 1d)The relative chlorophyll content of rice was lower than that of the control,and the relative chlorophyll content of the flooding days(such as 5d)increased compared with the control.After flooding treatment,the net photosynthetic rate of each treated rice plant decreased,and the decrease of net photosynthetic rate gradually increased with the deepening of flooding depth and the prolongation of flooding time.As the depth of flooding deepens,the relative conductivity of rice plants increases more significantly.(3)The effects of waterlogging stress on rice yield were studied by analyzing the yield per pan and the ear weight,seed setting rate and 1000-grain weight.The results showed that the yield of whole flooding in the niddle and late stages of tillering was 1/1-ld.The seed setting rate and the number of grains per panicle were higher than the control,and the yield increased by more than 5%.The yield of rice treated in the rest of the growing period was reduced to some extent conq)ared with the control,and the flooding stress was aggravated,and the yield reduction was continuously increased.With the deepening of the flooding depth and the prolonged flooding time,the ear weight,the number of grains per panicle and the seed setting rate showed a decreasing trend,while the change of 1000-grain weight was not significant.(4)When the flooding depth was less than 50cm in the early tillering stage,the water storage days could last for 3 days.When the flooding depth was less than 40cm in the middle and late tillering stage,the water storage days could last for 3 days.When the flooding depth was less than 12cm in jointing stage,the water storage days could last for 5 days,and when the flooding depth was less than 24cm,the water storage days could last for 3 days.When the flooding depthwas less than 14cm in booting stage,the water storage days could last for 3 days,and when the depth of flooding was less than 28cm,the days of storage could last for 1 day.When the depth of flooding was less than 14cm,the days of storage could last for 5 days,and when the depth of flooding was less than 28cm,the days of storage could last for 3 days.