Response Of Growth And Development Of Potato Onions With Different Anti-bolting Characteristics To Temperature Changes

Potato onion（Allium cepa var.Agrogatum Don.）is an annual herb of the genus Liliaceae,its fleshy bulbs as the main edible organ,rich in nutrition and high medicinal value,it is has a good application and promotion prospect,which is the traditional characteristic vegetable crop type in Heilongjiang Province,the market demand shows an increasing trend year by year.Because potato onion does not blossom or rarely blossom,tillering bulbs are usually used for vegetative reproduction,and local variety resources are mixed,local breed resources are mixed,little of any breeding has been place.Potato onion often appears bolting in the process of production,which affects the yield and quality of potato onion.Research on plant bolting mainly focuses on Chinese cabbage,radish,cabbage,onion and other bulk vegetable crops,however,the mechanism research on potato onion has not been reported,low temperature is a necessary prerequisite for affecting potato onion bolting.It is of great theoretical and practical value to explore the physiological mechanism of low temperature induction,to clarify its growth and development process,to realize the regulation of potato onion bolting in the cultivation process.In this study,three germplasm resources of potato onion with different anti-bolting characteristics were selected as test materials,and under open-field cultivation conditions,studied the effects of sowing period on the growth and development of potato onion,and the differences in changes of related physiological indexes（SOD enzyme activity,POD enzyme activity,soluble sugar content,soluble protein content,C/N ratio,GA₃content,IAA content）and the Ac ADLFY gene expression;Under controlled environment,studied the effect of low temperature treatment on the development index and Ac ADLFY gene expression of potato onion with different anti-bolting characteristics.The main results are as follows:（1）The earlier the sowing period,the initial bolting period of easy to bolt potato onion is earlier,and the bolting rate increases.（2）There were differences in the effects of sowing period on developmental index and Ac ADLFY gene expression of potato onion with different anti-bolting characteristics;In the first and second periods,the SOD and POD enzyme activities of M18 and M09 both increased first and then decreased;In each sowing period,the C/N values of M18 and M09 showed similar trends,however,the trend of C/N values of M06 was significantly different from that of M18 and M09;During the three sowing periods,the GA₃content of M18 was all lowest at 45days after seeding,the IAA content of M18 increased in both the second and third sowing periods,M09 and M06 in the second and third sowing periods decreased first and then increased;The Ac ADLFY gene expression of M18,M09 and M06 was highest at 60d after sowing in the first sowing period,with the highest value of M18>M09>M06.（3）There were differences in the effects of sowing period on developmental index and Ac ADLFY gene expression of potato onion bolting and unbolting plants;During the first and second sowing periods,the SOD and POD enzyme activity,soluble sugar content,IAA content,ABA content and Ac ADLFY gene expression of bolting plants were significantly or extremely significantly higher than the unbolting plants,and the GA₃content and GA₃/IAA ratio were significantly or extremely significantly lower than those of unbolting plants.（4）Low temperature treatment had different effects on development index and Ac ADLFY gene expression of potato onion with different anti-bolt characteristics;M18 and M09 were transferred to high temperature long sunshine environment after low temperature treatment,similar trends were observed for SOD and POD enzyme activity,C/N values,the contents of GA₃,IAA,soluble sugar,soluble protein and Ac ADLFY gene expression,the trends of various developmental indicators and Ac ADLFY gene expression of M06 were significantly different from those of M18 and M09.In conclusion,sowing period and low temperature treatment had a great influence on the development index and Ac ADLFY gene expression of potato onions with different anti-bolting characteristics,so under different sowing period conditions,there are obvious differences in the bolting rate of potato onion with different anti-bolting characteristics.