Study On The Effects Of High Temperature Stress On Flower Bud Differentiation And Mechanism Of Physalis Pubescens L.

physalis pubescens L.is an annual herbaceous plant of the family Solanum physalis,which is used for both medicine and food.It is mainly planted in the northeast of China.In the south,a large number of berries will be exposed outside the enlarged calyx,which will affect the quality and yield of the fruit.In this study,the varieties of"Dahuang guniang"physalis pubescens L.were used as test objects.During the flower bud differentiation period,23℃/16℃（T1）,27℃/20℃（CK）,31℃/24℃（T2）,and 35℃/28℃（T1）different temperature treatments to study the changes of morphological differentiation process of hair buds and the physiological changes of carbohydrates,total nitrogen,antioxidant enzymes and plant hormones during flower bud differentiation,in order to find out the cause of malformed fruit of physalis pubescens L.and provide theoretical basis for regulating the normal flower bud differentiation of physalis pubescens L..The main conclusions are as follows:1.The entire flower bud differentiation process of physalis pubescens L.is divided into five periods,namely undifferentiated period,differentiated period,sepal petal differentiation period,stamen differentiation period and pistil differentiation period.2.Under T1 and CK treatment conditions,the flower bud differentiation process of physalis pubescens L.was completely the same.The T2 and T3 treatments not only started flower bud differentiation earlier than CK,but also completed the flower bud differentiation process earlier than CK.In addition,compared with CK,the sepal primordial differentiation under high temperature stress did not form a closed sleeve-like structure,and in the later stage,the fruit was exposed outside the persistent calyx.The fruits harvested under T2 and T3 treatments had a deformed fruit ratio of 50%;the fruits of CK and T1 were normal fruits.3.Changes in carbohydrates:During the flower bud differentiation process of physalis pubescens L.under four different temperature treatments,soluble sugars and fructose are on the rise as a whole;Under high temperature stress,starch,sucrose,and reducing sugar all decreased first,then increased,and then decreased,and the content of reducing sugar was far less than that of CK.For sucrose,in the 3L stage,high temperature stress physalis pubescens L.undergo sepal differentiation.At this time,the sucrose content of the leaves reached a minimum,indicating that sepal differentiation consumes a large amount of sucrose content,which may result in the sepal primordium not forming an enveloping sleeve Structure,Perennial calyx.4.Changes in total nitrogen content:The total nitrogen content of T1 treatment showed a downward trend;the total nitrogen content of CK treatment increased first,then decreased and then increased;however,the total nitrogen content of T2 and T3 treatments was opposite to CK.5.Changes in antioxidant enzymes:SOD and POD activities under high temperature stress showed an overall upward trend during the differentiation process of hair bud pulp,while CAT activities were the same as T1 and CK,showing a trend of first increase and then decrease;but The decrease of CAT activity under high temperature stress was greater than that of CK.6.Changes in endogenous hormones:The contents of ABA,IAA,ZR and GA₃all increased first and then decreased under high temperature stress,and the overall level was higher than CK.Under T2 and T3 treatments,the ratio of ABA/IAA to ZR/IAA during the flower bud differentiation process of physalis was lower than CK as a whole,and ABA/GA₃and ZR/GA₃were higher than CK as a whole;In the 3L,5L,and 6L phases,the ABA/GA₃ratio of T2 and T3 treatments showed an upward trend,and the ZR/GA₃ratio showed a downward trend.