Effects Of Photoperiod On PhyA MRNA, PhyB MRNA And Plants Hormones In Different Medicago Sativa Fall Dormancy Varirties

Alfalfa as the main legumes, its yield has been especially concerned by people, fall-dormancy, a influence factor of yield, has become the major object of our study. Alfalfa was long-day plant, sunshine become shorter can affect its growth duration, this indicated that alfalfa had photoperiodic effect, phytochrome is the main photoreceptor, it is speculated that phyA,phyB gene were the major photoreceptors of alfalfa fall-dormancy. Therefore it is important for us to study the effect of RNA content of phyA and phyB and plant hormones IAA,GA₃,ZR ABA on fall-dormancy.In this study, we chosen three standard varieties fall dormancy cultivar (Norseman), semi-fall dormancy cultivar( Archer) non-fall dormancy cultivar (Cuf101) as the test material,4 replicates were set for each cultivar,sampling in four different photoperiodic time of June, August, September, November respectively,and leaf collection was commenced from the second film of the terminal bud leaf collection,the content of phyA, phyB mRNA and the change of four plant hormones( IAA, GA₃, ZR and ABA )were measured.The results were as follows:Test one,the influence of photoperiod on phyA, phyB mRNA content of different cultivars of fall dormancy.The results showed that:Respectively in June, August, September, November,the difference of the PhyA content between of Norseman and Archer was significant(P<0.01)and gradually increased,the difference of Cuf101 in June and August wasn't significant and showed a gradually increasing trend in numerical.Between the different months, phyA content of three tested varieties were different, but had no significant variation. PhyB content was different in the four months and had gradually increasing trend . the three species were different in different months, fall dormancy (Norseman)> semi-fall dormancy(Arche)> non-dormancy (Cuf101).Conclusion: with the shorter duration of sunshine, phyA, phyB content increased gradually in different varieties, phyB content increased with the enhancement of fall dormancy.Test two, the effect of photoperiod on IAA, GA₃, ZR, ABA content of different varieties of fall dormancy.The results showed that: IAA, GA₃, ZR content of three tested varieties existed difference in June, August, September, November, and showed decreasing trend, ABA content was difference but had the growing trend. In different months, hormone content of three varieties were different, but had no significant variation. Conclusion: with the shorter duration of sunshine, IAA, GA₃, ZR content decreased, ABA content increased. IAA, GA₃, ZR played the antagonism from ABA ,and the content were negatively correlated,the four plant hormones worked commonly in the regulation of physiological changes.