The Study On Physiological Characters Of Wheat Of Inverted Senescing Sequence Under Drought Condition

Inverted senescing wheat varieties Wenmai19, Lankaoaizao8, Yumai19and conventionalWheat Variety Shaan229as wheat materials were used in experiments.By a year fieldexperiment,we study the chlorophyll SPAD value, chlorophyll fluorescence parameters,photosynthetic parameters, autioxidant enzyme activities and dry matter accumulation of flagleaf and top2nd leaf,and the effect of drought stress to Inverted Senescing phenomenon. Ithas proved the advantages of Inverted senescing wheat variety and provided a new approachto wheat breeding. The major findings are as follows:1.Compared with conventional condition, the chlorophyll SPAD value, Fv/Fm，ΦPSⅡ，Fv/F0，F0/Fm of inverted senescing wheat varieties Wenmai19, Lankaoaizao8, Yumai19presentphenomenon that the top2nd leaf exceeds that of the flag leaf earlier and more significant.2.The chlorophyll SPAD value, the photosynthetic rate,stomatal conductance andtranspiration rate of the top2nd leaf exceeds that of the flag leaf under drought condition,theinverted senescing phenomenon presents earlier and more significant.3. The antioxidant enzyme activities increases at the earlier stage of drought stress and ittends to drop off over time. With inverted senescing phenomenon, the antioxidant enzymeactivities of SOD、POD、CAT of the top2nd leaf exceeds that of the flag leaf and less contentof MDA. The antioxidant enzyme activities present phenomenon that the top2nd leaf exceedsthat of the flag leaf6d earlier and more significant than than under conventional condition.4. The inverted senescing phenomenon present earlier under drought condition.During30-42d after anthesis,the flag leaf fill less and the top2nd leaf of Wenmai19, Lankaoaizao8,Yumai19fill about20.47%，28.28%，24.41%of total dry weight. During30-42d afteranthesis,the shaan229as conventional species only fill about5.12%of total dry weight.