This group is interested in molecular control and cell biology of plant cell growth and development response to gravity. The research is centred on the effects of microgravity on plant development and metabolism, the proteomic study to analyzing responses of plant to microgravity, involvement of cytoskeleton in gravity signal transduction effects of the biocontrol agent on the growth of watrer hyacinth (Erchhornia crassipes).

Principal Investigator: Dr. Hui-Qiong Zheng, Professor. Email: hqzheng@ sippe.ac.cn
Staff: Dr. Yue Zhang, Research Assistant; Xiao-Jing Wei, Research Intern; Liu-Fa Wang, Senior Technician; Ai-Di Chen
Graduate Students: Ning Wei; Chao Tan; Guo-Xing Xu; Bin Qi

Effects of Salt and Osmotic Stress on the Apoplastic Barrier Development and Water Transportation of Zea mays Seedling Roots
The development of the apoplastic barriers was studied in 8-d-old Zea mays seedling roots grown in hydroculture solution containing 100 mmol/L NaCl, or 20% polyethyleneglycol (PEG). A clear response of maize roots to these two kinds of stresses was observed. In both PEG-treated and NaCl-treated roots, endodermal casparian bands appeared closer to the root tip compared with those in the control roots, but the effects of salt and osmotic stress on the cell wall modifications of endodermis and exdodermis varied. Salt stress induced the formation of strong multiserate exdodimis but not significantly influenced the cell wall modification of endodermis. In contrast, osmotic stress speeded the formation of both endodermis and exdodimis. The hydrostatic hydraulic conductivity (Lp) was determined in both salt and osmotic stress roots. In the case of PEG stress condition, Lp decreased significantly one day after treatment, while Lp of NaCl-treated roots decreased to the similar level as long as five days after treatment. The data indicate that effects of salt stress and osmotic stress on the apoplastic barrier development and water transportation in Zea mays seedling roots might be different.

A Proteomic Approach to Analyzing Responses of Arabidopsis thaliana Root Apex Cells to Different Gravitational Conditions Using an Agravitropic Mutant, Atpin2 and its Wild Type
A systematic proteomic approach has been performed to investigate the altered gravity responsive proteins in root tips of Arabidopsis thaliana wild type (cv. Columbia) and a gravity-insensitive Atpin2 mutant. Six-day-old seedlings were exposed to a horizontal clinostat rotation (H, simulated weightlessness), a hypergravity treatment by centrifugation (G, 7g hypergravity), a vertical clinostat rotation (V, clinostat control), or a stationary control grown condition (S). Total proteins of roots were extracted and separated by two-dimensional (2-D) gel electrophoresis. About 1300-1500 protein spots were reproducibly detected, including 88 protein spots showed quantitative and qualitative variations that were significant (P<0.05) and reproducibly different between altered gravity treated (H , V or G) and the stationary control samples. 28 protein spots, which showed significant expression alteration only under the H or G conditions compared with those under V and S condition, were identified as 25 different proteins. About 65% and 21% of these protein spots in the H and the G samples, respectively, had very different patterns of protein expression between Atpin2 and wild type.

Major Publications:

1. 郑慧琼, 魏宁, 陈爱地, 王六发. (2008) 空间飞行与回转器回旋条件下青菜花开花与花粉发育的研究. 空间科学学报 28: 80-87.

2. Zheng HQ, Wang H, Wei N, Chen AD, Wang LF, Zheng WB, Lu JR, Zhang T. (2008) Live imaging technique for studies of growth and development of Chinese cabbage under microgravity in a recoverable satellite (SJ-8). Microgravity Science and Technology 20: 137-143.

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