Quantitative Study On The Effects Of Waterloging During Full Blooming On Sesame Growth

Waterlogging is the most harmful factor to the production of sesame,which may lead to dramatic production decline or even no harvests.During the whole sesame growth period,flowering is the most susceptible stage to waterlogging.Therefore,quantitative research on sesame growth,development,photo synthetic accumulation and subsequent distribution of assimilation substance under waterlogging condition at full blooming stage will provide valuable information for sesame productivity forecast,waterlogging assessment,early warning for waterlogging,and which can also lay the foundation for establishing the sesame waterlogging model.The pot experiment was conducted with two different waterlogging tolerant varieties of sesame(high waterlogging tolerance variety Zhongzhil3 and waterlogging sensitive variety Zhengzhi13)as research materials,and then at full blooming stage,sesame were exposed to waterlogging for Oh,24h,36h,48h and 60h respectively.From the 2-3 leaf period,every three days,measuring the stationary plant with height and leaf age in different treatments,sampling every 5 days to measure leaf area of whole plant and dry weight of each organ.The relative days after emergence are used as the unit of metric,we simulation analysis the plant height,leaf age,leaf area index,dry matter accumulation and distribution under the waterlogged environment between these two sesame varieties.The results are as follows:1.The relationship between traits,such as height,leaf age and dry matter accumulation of sesame and the corresponding postemergence time are all in line with Logistic curve at a statistically significant level.Through the analysis of the parameters of Logistic equation and the secondary parameters shows that:waterlogging increased the growth rate of plant height,more specifically,as the waterlogging time increasing,the growth rate of height become slower,at the end,we found that the plant height increased significantly compared with the control under 24h waterlogging treatments for both two varieties,while there was no significant difference when these two cultivars continued suffering from waterlogging for 36h.Waterlogging also reduced the growth rate of leaf age,and with the increased processing time,the effect was more obvious.Waterlogging reduced the dry matter accumulation rate,and this negative effect was aggravated with the waterlogging time increasing.The dry weight of Zhongzhil3 and Zhengzhil3 was decreased significantly compared with the control when they were exposed to waterlogging for 36h and 24h respectively2.The relationship between the relative LAI and the relative postemergence dayscan be fitted by Gauss equation and the fitting coefficients were all above 0.89.By analyzing the fitting parameters of the two cultivars under waterlogging,we may find that the maximum value of LAI in all waterlogging treatments were significantly lower than the control,and the LAI reached maximum ahead of the control as well.3.The relationship of the relative distibution index of leaves in sesame with the relative postemergence days can be fitted with and quadratic polynomials curve,respectively.The relationship between relative partitioning index of capsule and the relative number of days after flowering followed the Logistic curve.All fitting results reached significant level.Based on the studies parameters,we found that waterlogging had no significant effect on the partitioning index in sesame,but the parameter k of the capsule partitioning index reduced gradually as waterlogging time continuing,and it can reached extremely significant level in Zhengzhi 13 under waterlogging for 48h.So it can be deduced that waterlogging can reduce the partitioning index of capsule,but has little effect on partitioning index of leaves.Above all:both the relationship between plant height,leaf age and dry matter accumulation of sesame and the postemergence days,and that between capsule distribution index and the number of days after flowering are all in line with Logistic curve;the relationship between LAI and the postemergence days follows with Gauss curve;the relationship between leaf distribution index and the postemergence days can be fitted with quadratic polynomials curve,respectively.Waterlogging at the full blooming stage of sesame will improve the plant growth rate while reduce the leaf age growth rate,result that making the time LAI reach the maximum in advance,but the maximum value decreased;Waterlogging also reduce the dry matter accumulation rate and the capsule distribution index,while the stem distribution index increased.