Dynamic Analysis of Bark Structure and Latex Physiology During Promoting the Latex Regeneration of Tapping Panel Dryness (TPD) Trees in Hevea brasiliensis

1−MCP was used to promote the latex regeneration of tapping panel dryness(TPD) trees in this study. The bark structure and latex physiological parameters, such as latex yield, inorganic phosphorus, thiol, sucrose contents and lutoid bursting index, were measured during TPD tree recovery. The results showed that the bark structures of TPD trees had an obvious change during TPD tree recovery. The number of effective laticifers increased in yellow skin, and the areas of stone cells and swelling laticifers decreased in the barks. From the changes of latex physiological parameters, the latex yield showed a significant increase trend during TPD tree recovery. The latex yield of TPD trees from the control was 19.89 mL, and the yield significantly rose to the maximum of 151.17 mL when the TPD trees recovered the latex flow. The thiol and inorganic phosphorus both firstly decreased and then increased. The contents of thiol and inorganic phosphorus were 0.64 mmol/L and 11.26 mmol/L before treatments, respectively. Their contents both significantly rose to the maximum of 1.19 mmol/L and 14.56 mmol/L when the TPD trees recovered the latex flow, respectively. The sucrose content had an obvious rise trend, which is consistent with the change of latex yield. However, the lutoid bursting index significantly dropped to the minimum of 13.47% when the TPD trees recovered the latex flow. Overall, the changes of the thiol, inorganic phosphorus and sucrose contents were positive correlations with the latex yield, and the change of the lutoid bursting index was negative correlation with the latex yield during TPD tree recovery.