Effect Of Plant Growth Regulator （GA₃,PP333,ABA） In Growth And Development And Cold-resistence Of Armeniaca Vulgaris Cv.‘Luntaibaixing’

There were several factors that contribute to low production of Luntaibaixing.such as,the natural fruit setting rate was low and fruit was small,in addition,flourishing growth of young trees leads to flowering and fructification late.In order to explore the regulatory role of plant growth regulator on the growth and development of Luntaibaixing,the index of fruit development,shoot and leaf growth were measured after spraying GA₃,PP333 and ABA.The effects of these three growth regulators on growth and development of Luntaibaixing were analyzed.（1）The results showed that 65 mg/L and 90 mg/L GA₃ treatment increased fruit setting rate of Luntaibaixing.They increased by 10.65%and 9.30%respectively when compared to CK.The vertical diameter and transverse diameter of fruits treated with 65 mg/L GA₃ respectively increased by16.50%and 14.06%.The concentration of 90 mg/L GA₃ treatment increased by 10.78%and 9.21%.According to the observation of fruit tissue structure,the vertical diameter of the mesocarp cells increased significantly.Compare to CK,65 mg/L and 90 mg/L GA₃ treatment have increased 19.83μm and 16.16μm respectively.While the transverse diameter and cell layer had no significant effect.The results also showed that the size of seedlings decreased gradually with the GA₃ concentration increase.In addition,this study also showed that high concentration GA₃treatment is not conducive to improving fruit quality.（2）After the treatment of PP333 and ABA,the treatment of 1000 mg/L PP333 and 60 mg/L ABA were able to control the growth of the new shoots well,and had little effect on the fruit quality.The results showed that the new shoot length,internode length and leaf area showed a decline trend,when applied with 1000 mg/L PP333 and 60 mg/L ABA treatment,the new shoots length decreased by18.37%、13.89%,the internode length decreased by 4.49%,5.87%,the leaf area decreased by 29.36%and 28.72%.While the new shoots of coarseness increased by 8.82%,10.66%and chlorophyll value increased by 8.68%,8.49%.By observing the leaf tissue structure,the results showed that except2000 mg/L PP333 and 30 mg/L ABA treatment no significant difference with CK,the other treatments were significantly different from CK.The leaves thickness,palisade tissue,the value of CTR all increased significantly,while the value of SR reduced significantly.In addition,soluble solids,Vc content,soluble total sugar content,sugar acid ratio increased,and titratable acid content decreased.（3）The treatment of 1000 mg/L PP333 and 60 mg/L ABA significantly improved the photosynthesis and Photosynthesis fluorescent parameters of Luntaibaixing.The chlorophyll a and chlorophyll a+b content increased significantly.When compare to CK,the chlorophyll a was increased by 14.49%and 9.74%,and that chlorophyll a+b increased by 18.92%and 30.19%respectively.There was no significant effect on chlorophyll b and carotenoid content.The Pn,Gs and Tr increased and then decreased,but the Ci decreased with the concentration of PP333 and ABA were increased.Compared to CK,Fo decreased by 10.63%and 11.80%,while q P and Fv/Fm increased by 41.73%,53.42%and 71.00%,10.99%.（4）The contents of ABA in new shoots and the ratio of ABA/GA,ABA/IAA were significantly increased after disposing with 1000 mg/L PP333 and 60 mg/L ABA treatment,while the contents of GA and IAA were reduced.The relative electrical conductivity and MDA content decreased by 3.64%、3.27%and 7.93%、6.55%,while the content of soluble sugar,soluble protein,and Pro increased by14.36%,10.77%,26.72%,28.77%,23.37%、25.35%when applied with 1000 mg/L PP333 and 60mg/L ABA treatment.The result showed that LT₅₀ decreased by 2.82℃and 1.35℃respectively,and effectively improve the cold resistance of Luntaibaixing,when disposed the new shoots with 1000mg/L PP333 and 60 mg/L ABA during its rapid growth period.