Comparative Study on the Seasonal Variation of Latex Physiological Characters from three Hevea Clone
Young tapping Hevea trees,from 3 clones(Reyan 8-79,Reyan 7-33-97,PR107),were exploited with S/2 d3 tapping systems.Seasonal variations of rubber yield,latex invertase activity,and physiological parameters were analyzed and comparatively studied.Results showed that,in almost tapping periods,rubber yield,latex invertase activity,pH value of Reyan 8-79 were higher than that of Reyan 7-33-97 and PR107,sucrose content lower than that of Reyan 7-33-97 and the later lower than that of PR107,the differences of total solid content among 3 clones were not significant.Results indicated that Reyan 8-79 possessed higher rate of sucrose utilization in laticiferous system and higher capability of latex regeneration,while PR107 possessed inverse characteristics.Three high-rubber-yield periods were commonly formed in May,July to August and October to November,respectively,while different clones possessed different durations in same high-rubber-yield periods.In the period of middle April to early May,rubber yield,invertase activity,pH value,sucrose content increased successively,total solid content decreased,in each clone,indicating that latex regeneration increased and latex flow became easier in this period.In other tapping periods,the trends of rubber yield,invertase activity and physiological parameters were complicated and often synchronous,indicating that rubber yield affected by many factors.The results of this research may provide reference to lay down suitable tapping system for these clones.