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CHANGES IN ABSCISIC ACID IMMUNOLOCALIZATION IN HEAT-STRESSED PEPPER SEEDLINGS

LIU TONG-XIANG¹, ZHANG ZONG-SHEN^2*, WAMG JIAN-BO³ AND LI RONG-QIAN³

Abstract: The heat stress-responsive abscisic acid (ABA) subcellular distribution in pepper mesophyll and root cap cells was investigated by colloidal gold labeling technique. The results showed that the ABA was localized in the nucleus and the cytoplasm of two cell types in the seedlings under normal temperature, with relatively a higher accumulation in the root cap cells. As the seedlings were transferred to 40^oC for heat stress, the ABA levels in both mesophyll and root cap cells increased markedly, especially in the later. With a sustained heat stress, the ultrastructure of mesophyll cell was severely damaged and more ABA accumulated in the nucleus of mesophyll cells; comparably, the root cap cell maintained intact ultrastructurally, and a concomitant drastic increase in ABA in the nucleus of root cap cells was also observed. The above results imply that ABA might be one of the heat stress signaling members in plant cells, whereas the mechanism by which ABA functions during this process remains poorly understood.

¹China Minority Traditional Medical Center, Minzu University of  China, Beijing 100081,China;

²School of Biology and Food Engineering, Dalian Polytechnic University, Dalian 116034 China;

³Key Laboratory for Developmental Biology of MOE, Wuhan University, Wuhan 430072 China.
Corresponding author E-mail: zhangzs@dlpu.edu.cn