| Emmenopterys henryi Oliv.is a unique single genus in China.It is an important material for studying the phylogeny,morphological evolution and flora of Rubiaceae in China.It is also an excellent material for architecture,furniture,carving models and interior decoration.It can also be used to make wax paper and artificial cotton.As an autumn flower plant,it is also an excellent tree species for landscaping.At present,it is in an endangered state and is listed as a national class II protected plant.This subject used the seedlings of Emmenopterys henryi Oliv.obtained by tissue culture as the material,and conducted two researches.First of all,the heat resistance of Emmenopterys henryi Oliv.was evaluated,and the effects of trehalose on the physiological,biochemical,growth and development under high temperature stress were studied,in order to clarify the signal function of trehalose in the regulation of Emmenopterys henryi Oliv.heat tolerance.The main test results are as follows:1.Emmenopterys henryi Oliv.seedlings were exposed to high temperature stress,reducing their own damage by shedding leaves,and at the same time reducing Pn,Gs and Tr to deal with the stress;Seedling had a certain degree of heat resistance,which can be restored to normal levels within a certain period of time when the high temperature stress was continued for 3 or even 6 days;the heat resistance level of the Emmenopterys henryi Oliv.was not high,and the Emmenopterys henryi Oliv.seedlings can’t recover after 9 days of continuous high temperature stress.At normal levels,the organic matter had decreased,indicating that the heat resistance critical point of the Emmenopterys henryi Oliv.had been reached at this time.Under the conditions of a high temperature of 43℃,a temperature difference of 5℃between day and night,a day and night time of 12h:12h,an air humidity of 70%,and a stress time of 9d,the compensatory growth of the seedlings of Emmenopterys henryi Oliv.had reached its limit.2.Exogenous addition of trehalose can effectively alleviate the decrease of Pn in the seedlings of Emmenopterys henryi Oliv.caused by high temperature,maintained the stability of Gs and Tr,and reduced the content of Ci at the same time;for Fm,Fv/Fm,Fv/Fo,q P,Y（II）,ETR had a certain mitigation effect,slowed the decrease of Fo and returned NPQ to the normal range;in addition,adding trehalose can increase the content of chlorophyll a,b and reduce the content of anthocyanin in the seedlings of Emmenopterys henryi Oliv.after high temperature stress.It showed that trehalose can alleviate the damage of high temperature stress to the photosynthetic system of Emmenopterys henryi Oliv.seedlings to a certain extent and maintain the stability of the photosynthetic system.3.Trehalose treatment can increase the relative water content of the leaves of Emmenopterys henryi Oliv.seedlings under high temperature stress,reduced the electricalconductivity and the content of MDA,H2O2and O2-,increased the activity of SOD,POD,CAT and APX enzymes,and in the slow seedling stage,The antioxidant enzyme activity and MDA in the seedlings of trehalose had returned to normal levels.It showed that trehalose can alleviate the damage of antioxidant system and plasma membrane caused by high temperature to the seedlings of Emmenopterys henryi Oliv.,and maintain normal growth of seedlings of Emmenopterys henryi Oliv.. |
