Effects Of Exogenous Spermidine And Polyamine Synthesis Inhibitor On Polyamine Content In Latex Rubber Tree

Rubber tree(Hevea brasiliensis)is a typical tall tropical tree,and its latex is a main material for natural rubber.China is the largest consumer of natural rubber worldwide,and the self-sufficiency of natural rubber has been less than 20%since 2009.Raising selfsufficiency by improving latex yield of rubber tree has become the main problem faced by China’s natural rubber industry.The typical symptom of tapping panel dryness(TPD)is the appearance of partial dry zones(no latex flow)along partial or whole tapping panel,and it is the key limiting factor on improving latex yield of rubber tree;therefore controlling TPD is a prerequisite to improve latex yield of rubber tree.The latex is harvested by tapping rubber tree bark,and tapping is helpful for latex biosynthesis which is a growth phenomena.As ubiquitous low molecular weight aliphatic nirtrogenous bases,polyamines(PAs)are widely present in prokaryotic and eukaryotic organisms.Besides regulating plant growth and development,PAs play important roles on abiotic and biotic stress responses.However,the effect of exogenous Spd and MGBG application on PAs contents has not been reported yet.In this study,healthy and TPD rubber tree clone(Reyan 7-33-97)were selected as experimental materials.The control(H2O),Spd,and MGBG were smeared on 2 cm above the tapping panel,and then the contents of Put,Spm,and Spd were measured under the aforementioned treatments.Analyzing the effects of SPD and MGBG treatment on polyamine content in latex between TPD and healthy rubber tree,we obtained the results as followings:By optimizing two key factors(additive amount and derivation time of benzoyl chloride)that have major impact on PAs measure,we obtained reliable and high performance liquid chromatography(HPLC)method for measuring PAs as following:additive amount and derivation time of benzoyl chloride are separately are 10μL and 40 min;the column model of C18 reverse liquid chromatography is Eclipse Plus C18(250 mm × 4.6 mm × 5 μm),and column temperature is 30℃;The mobile phase is water and acetonitrile,and the volume ratio is 56:44;The total injection volume is 20 mL,and the flow rate and detection wavelength are separately 0.7 mL·min-1 and 230 nm with isometric elution.To make measuring results reliable and accurate,light shielding is required for both derivative and post-derivative samples and derivative test should be detected by HPLC as soon as possible.Except for Spm content at 0 and 24h,the contents of Put,Spd,and Spm in TPD rubber tree latex are higher than healthy one without treatment.In contrast to the control,the contents of Put,Spd,and Spm in TPD and healthy rubber tree latex are raised after Spd treatment of 24 and 48 h,and the highest content value occurs on 48 h after Spd treatment.Different from Spd treatment,the contents of Put,Spd,and Spm in TPD and healthy rubber tree latex are decreased after MGBG treatment of 24 and 48 h.Except for Put content at 48 h after Spd treatment and Spm content at 48 h after MGBG treatment,the contents of Put,Spd,and Spm in TPD rubber tree latex are higher than healthy one in their corresponding time points after Spd and MGBG treatments.Under the control conditions,the total content of Put,Spd,and Spm in TPD rubber tree latex was higher than that in healthy rubber trees.After exogenous application of Spd treatment,the total content of Put,Spd,and Spm in TPD and healthy rubber tree latex increased,while the total content of Put,Spd,and Spm in TPD and healthy rubber tree latex decreased after the application of MGBG treatments.Except for at 48 h after Spd treatment,the sum of Put,Spd and Spm in TPD rubber tree latex are higher than healthy one in their corresponding time points.These results suggested that the contents of Put,Spd,and Spm in latex can be regulated by Spd and MGBG treatments in TPD and healthy rubber tree.