Effect of substrate moisture at high temperature on tissue structure and seedling growth physiology of potato seed potato
[Objective]To investigate the effects of different cultivation humidity and seed potato status on seed potato vigour,germination and seedling establishment in potato at high temperatures.[Method]The potato variety"Xingjia 2"was selected as the test material,and was designed to simulate drought,normal and high humidity conditions under high temperature(30℃)stress with three different cultivated substrate humidity levels,namely 30%,60%and 80%,and"healthy whole potatoes","healthy whole potatoes","partially damaged whole potatoes"and"cut potatoes".Dynamic changes in cell viability and tissue structure of different treated seed potatoes were analysed at the budding stage,and their growth and physiological status were comprehensively evaluated at the seedling stage of different treated plants.[Result]Compared with the dormant period,the seed potato in the sprouting period has vigorous life activities,the respiratory decomposition of sugars for the energy supply of the body,the soluble sugar and soluble protein content,SOD activity and respiratory strength have increased to different degrees,while malondialdehyde content and seed potato hardness have decreased;The greater the degree of seed potato damage,the faster the formation of tuber cell cavities and disintegration of vascular bundles under high temperature,in which the cut potato starts to change from the pith department,the degree of damage is the greatest,and the speed of change is also the fastest,and the damaged potato starts to change from the vascular bundles at the very beginning,and then spreads upwards to the terminal buds and downwards to the pith department at the same time,and spreads downwards faster,and the damage is serious,and the whole potato starts to be the buds blackened,and the conductive tissues are gradually broken,and the degree of damage is relatively the integrity of seed potato is better;The effect of high temperature on seed potato germination is drastic,the greater the cultivation humidity,the faster the seed potato emergence rate,80%cultivation humidity seed potato emergence rate is significantly lower than 30%cultivation humidity,but the fastest rate of emergence,the same humidity of different seed potato state,the whole seed potato emergence rate is slow but neat,and damage to the potato and the cut potato emergence rate is relatively fast but low rate of emergence.[Conclusion]High temperature and high humidity composite stress on potato seed potato is greater than a single high temperature stress,in high temperature adversity seed potato block cracks,after the cell wall rupture,cell membrane contraction,the formation of cavities,affecting the rate of seedling emergence and seedling rate,so in the potato autumn should be sown before 2-3 days of irrigation,avoid high temperature weather sowing after heavy irrigation,avoid high temperature weather before heavy rain sowing,choose the sprouting period of the small whole potatoes sowing,you can rapidly Seedling and get high seedling rate,to ensure the autumn potato stable yield.This study analyzed the histocytological and physiological changes in autumn-sown seed potatoes,and provided theoretical references for the reduction of rotting seed potatoes in autumn cropping through the application of effective agronomic measures and the promotion of farmers'income.
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