TY  - BOOK
AU  - Jilin Wu
AU  - Bingzhong Hao
AU  - Haiyan Tan
AU  - Shoucai Chen
TI  - Histological and cytological aspects of tapping panel dryness induced by overstimulation with ethrel in Hevea brasiliensis
PB  - IRRDB Conference: NR Industry: Responding to Globalization 7-8 September 2004, Kunming International Convention & Exhibition Center, China
KW  - Ethrel
KW  - Tapping panel dryness
N2  - Materials and methods: The twenty-five year old PB86 and RRIM 600 rubber trees grown in the experimental farm of our Academy were tapped on s/2 d/3 and stimulated with 8;ethrel at fifteen day intervals. Histological and cytological aspects of tapping panel dryness (TPD) induced by the overstimulation were studied using light microscopy and transmission electron microscopy. Results: 1.With the course of overstimulation tapping laticifer death occurred near tapping cut first in the outer bark and gradually towards the inner bark. 2.Senescence of organelles was accelerated in the survived laticifers. Myelin-like structures appeared in the laticifers. Some lutoids became residual bodies and F-W particles became electron dense. Nuclei had broken membrane and condensed chromatin. The content of the nuclei could finally disappeared. 3.In situ latex coagulation was an essential characteristic of laticifer senescence. It was quite different from the process normally occurring at laticifer wounds after tapping. Along with the in situ latex coagulation, it was found that lutoids abnormally accumulated in the laticifer vessels at some distance from tapping cut and that empty laticifer vessels appeared in the middle and inner bark. 4.In the laticifers the quantity of rubber particles was less, most of which were smaller. 5.Senescence of bark tissue was accelerated. Discussion: 1. The onset of the TPD induced by overstimulation with ethrel is a process of accelerated senescence. 2.Disorganization of membrane structures of organelles is an essential characteristic of senescent laticifers. 3.The laticifers of TPD induced by overstimulation might loss their defecse function. The overstimulation induced TPD could develop the necrotic symptom when trees continued to be exproited with overstimulation
ER  -