Physiological Mechanism And Transcriptome Analysis Of The Tolerance Of Poplar To Drought Stress

This paper is based on 6 year old poplar hybrid combinations,including maternal I-101 poplar(P.abla),paternal 84 K poplar(P.glandulosa),and Selective breeding of superior progeny clones(21-13)from their hybrid as experimental material,under the four kinds of typical soil moisture environment determination analysis of poplar parental,hybrid offspring growth and resistance physiology of drought.Four kinds of soil water environment were the surface dry semi arid environment(W1),the dry environment(W2),the surface layer and the deep dry environment(W3),and the humid environment(W4).This study revealed that the growth and WUE of hybrid progeny were significantly superior to the parental and the control group.It was proved that the new hybrid breeding of drought resistant and drought tolerance poplar hybrid has strong feasibility and application prospects.In W1 environment,hybrid progeny can be adapted to semi-arid environments well by reduced stomatal conductance and transpiration rate;In W3 environment,hybrid progeny of Pn was significantly higher than that of the male and female,Thus maintained a relatively stable WUEi and dry matter production capacity.This confirmed that cross breeding is expected to poplar improvement of stomatal regulation ability and the filial generation can maintain a certain photosynthetic rate and higher WUE while reduce transpiration rate and water dissipation and,finally produced stronger drought resistant ability and higher productivity than the parental.The relative differences of gas exchange parameters between the parents and the hybrid progeny were different in different soil water environment.W1 in hybrid progeny of WUEi was significantly higher than that of the male and female,shows that the hybrid progeny of WUEi has the highest heterosis in W1 is semi-arid environment of surface soil water.W3 hybrid progeny of Pn was significantly higher than that of the male and female,showed that under severe drought condition,the heterosis was the most significant of net photosynthetic rate of hybrid progeny.In the semi-arid environment of the deep-layer water shortage,the most increased is the proline synthesis.Under severe drought stress,the content of soluble sugar and POD accumulation in poplar was high.And continued to maintain the high accumulation characteristics after rewater,under the Severe drought stress,the content of ascorbic acid of poplar was the highest,There were significant differences drought resistance related physiological characters in hybrid progeny and their parents,and the variation law was different from different soil water environment.Poplar hybrids have stronger drought tolerance ability and maintain a high WUE and growth rate result from the genotype difference of free proline,soluble sugar and starch content.ASA is involved poplar physiologica response of drought stress mainly under the semi arid environment of surface soil water shortage.WUEi was negatively correlated with leaf P concentration and leaf N concentration,and WUEi was positively correlated with leaf N utilization efficiency and leaf P utilization efficiency,shows that utilization efficiency of N and P in Poplar will significantly promote the resistance to drought and water use efficiency.We use transcriptome sequencing technology to illustrate that the differential gene expression under severe drought stress and rewater conditions,confirms that most of the genes participation poplar drought resistance are secondary metabolism and biosynthesis,signal transduction,energy production and conversion aspects of the genes.