Characteristics Description Of Pear Superior Lines And Cultivars And Application Of Laxogenin C On Pear Tree

Fruit characteristics of several pear superior lines and cultivars in different phenological were been observed.Meanwhile ‘Zaosu’ pear and one superior line ‘9712’ were selected as materials to investigate the effect of laxogenin C on fruit quality,photosynthesis and fruit diseases.These results could provide evidences for improving field production or basic contents in pear study.The main results were as follows:1.The leaves,flowers and fruits characteristics of pear superior lines(‘9712’,‘2-49’,‘1543’,‘5-16’)were tested according to the testing standard of New Plant Cultivar DUS Testing Guideline of Pear.The ‘9712’ and ‘5-16’ were expected to be extremely early variety,because their maturity was at the end of June.The fruits of ‘9712’ has many advantages,such as crisp,succulent.The soluble solid of the 1543 was 14.4%,and the fruit had red halo.The superior line ‘2-49’ matured in September,and the fruit had red halo.So the ‘2-49’ could be a late-mature pear superior line.2.According to the standard in Chinese Fruit Tree Pear(handbooik),the leaves,flowers and fruits characteristics of pear cultivars(Liuyuesu,Hongxi,Hongsichou,Hongzaosu,Qingsu,Qiushuijing)were tested.3.We monitored the effects of laxogenin C on the quality of pear,photosynthesis characteristic and size of decayde parts of pear infected by anthracnose of pear(Zaosu).The results showed as followed: the optimal concentration of laxogenin C significantly affected the fruit weight,equtorial diameter,transverse diameter,soluble solid and ascorbic acid.Compared with contrast,fruit weight,equtorial diameter,transverse diameter,soluble solid and ascorbic acid had respectively increased 14.2%,17.4%,15.6%,15.5%,17.7% in 0.5mg/L laxogenin C.The optimum concentration of LG-C also promoted photosynthetic rate(Pn),stomatal conductance(Cond)and intercellular CO2 concentration(Ci),but there had no significant difference.In 0.1 mg/L LG-C,Pn,Cond and Ci had respectively increased 0.4%,14.8%,6.7%.And 0.5mg/L laxogenin C can significantly inhibit size of decayde parts.4.We also observed the effects of LG-C on the quality of pear,photosynthesis characteristic and size of decayde parts of pear infected by ring-rot disease of pear(2-49).The laxogenin C treatment caused a significant decrease in the fruit weight,equtorial diameter,transverse diameter and soluble solid compared with control.And it had increased 32.3%,19.6%,20.6%,16.9% respectively in 0.5mg/L laxogenin C.The Photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Cond)and intercellular CO2 concentration(Ci)of control individuals and other concentrations were inferior to those subjected to 0.1mg/L.And at the concentration,Pn,Tr,Cond and Ci had respectively increased 16.0%,58.4%,46.2% 11.6%.And 0.5mg/L laxogenin C had the best effect to inhibit size of decayde parts of pear infected by ring-rot disease.5.In pear,the laxogenin C could enhance the activity of POD、PPO 、SOD treated with anthrax bacteria and ring spot virus.At the 15 days treatment,the activity of POD、PPO 、SOD reached the optimum magnitude.POD、PPO 、SOD activities first increased in the fruit before gradually decreasing.The improvement in this activities was concentration-dependant up to 0.02 mg/L before declining.