Influence Of Plant Hormones On The Dwarfism Performance In Rice Variety Aiganpei'ai 64S

Rice dwarf germplasms have played an important function in production of hybrid rice.Detection and utilization of new dwarf rice resourses have became more and more important.After many years breeding practice,we have successfully transferred the dominant dwarf gene from Japonica rice KL908 to sterile rice yuanshipei'ai64S(YP64S), and get a new dominant dwarf rice aiganpei'ai64S(AP64S).At present,the research about the physiology characteristics of this new dwarf rice variety hasn't been reported yet.In order to investigate the physiology mechanism of dwarf character in dwarf rice. AP64S,zhenzhu'ai(ZZA) and YP64S whit different dwarf genes,hybrid rice ailiangyoupeijiu(ALY,AP64S/9311),liangyoupeijiu(LY,YP64S/9311),and tall rice 9311 were explored to discuss the effect mechanism of hormones in rice normal growth,and explored the effect of GA₃ and PP₃₃₃ on endogenous hormones in rice at seedings, tillering and internode elongation stages,physiological effect of dwarf gene were analyzed in several aspects such as amylase activity in the germinated seeds,the chlorophyll content,Enzyme activity of POD and peroxidase isoenzymes.The results are discussed as follows:1.The plant height of hybrid rice ALY is 17.98%taller than its female parent AP64S,and 89.98%of the mean of its both parents,and degree of dominance in plant height is -0.50,indicating that the dwarf gene of AP64S is dominant,this dwarf gene can shorten the length of first and second internodes from the panicle,reduce the number of internodes,and inhibits the plant height.And therefore AP64S is a new sterile rice variety with dominant dwarf gene.2.The contents of GA₃ in AP64s,ZZA and YP64S is 65%to 82%of that of 9311 in internode elongation stage.The contents of ABA is 20%to 40%more than that of 9311. These results indicate that low content of GA₃ and high content of ABA in dwarf rice inhibit the plant height.3.After application 50 mg/L GA₃,the contents of GA₃ and IAA in AP64S in seedings and tillering stages are increased 14%to 66%,and the contents of ABA and the enzyme activity of POD are reduced 11%to 41%.The contents of GA₃ and IAA in AP64S in internode elongation stage are reduced 29%and 22%,and the contents of ABA and the enzyme activity of POD are increased 10%and 91%.After 50mg/L GA₃ are applied,the contents of GA₃ and IAA in ZZA in seedings and tillering stages are reduced 9%to 35%,and the contents of ABA and the enzyme activity of POD in seeding stage are increased 25%and 37%.The contents of GA₃ and IAA in ZZA in internode elongation stage are increased 23%and 29%,and the enzyme activity of POD is reduced 33%. 50mg/L GA₃ has a negative effect to the chlorophyll content in AP64S,whose chlorophyll content in AP64S are reduced 23%at seedlings stage.50mg/L GA₃ has negative effect to the chlorophyll content in ZZA in seedings and tillering stages,but has positive effect in internode elongation stage.The results indicate that the physiological and biochemical response of dwarf rice to exogenous GA₃ depend on its GA sensitivity and the growth period.The enzyme activity of POD can inhibit the contents of GA₃ and ABA.4.After treated with 200 mg/L PP₃₃₃,the contents of GA₃ and IAA in YP64S and LY are reduced in various growing periods,and the contents of ABA and chlorophyll and the enzyme activity of POD are increased.The results indicate that PP₃₃₃ can increase the contents of ABA and chlorophyll and the enzyme activity of POD,inhibits the plant height,and promotes the substance synthesis.YP64S is sensitive to PP₃₃₃ in seedlings stage,and LY is sensitive to PP₃₃₃ in internode elongation stage.5.There is no marked difference in the enzyme activities ofα-amylase in AP64S, ZZA and YP64S,which are all 18%more than that of 9311.The difference inβ-amylase activity between AP64S and 9311 is marked.After treated with 20mg/L GA₃,the activity ofα-amylase in AP64S,ZZA,YP64S and 9311 are increased respectively 22.66%, 9.13%,99.04%and 58.39%,and the activity ofβ-amylase are increased respectively 13.42%,43.75%,88.92%and 40.86%.The results indicate that GA₃ can induce synthesis ofα-amylase,and thus increase the activity ofα-amylase andβ-amylase.The sensitivity to GA₃ is in the order of YP64S＞9311＞AP64S＞ZZA.