B.Sc., Jiangsu Agri. Coll.; Ph.D., Lancaster

Chair Professor and Head of Department

Department of Biology, Hong Kong Baptist University

Director

MSc in Environmental and Public Health Management

Rm. T1017; (852) 3411-7050

• Plant physiology under environmental stresses
• Crop production under water-limited condition

Drought stress is the most important stress to both crop production and natural vegetation. For the natural vegetation, it is well known that the more rainfalls, the lusher the vegetation can be. For crop production, yield loss due to drought is the No. 1 cause among all the adverse factors that limit agricultural production.

My research ranges from elucidating plant molecular mechanisms when water stress is developing to the crop production in the field. At the molecular level, my lab focuses on the initial perception of water stress and the subsequent changes in gene expression. Identification of the genes involved, their roles during the stress perception and the physiological regulations they impose are the major direction of our research in recent years.

In a more applied water stress research, my team has been developing water-saving irrigation techniques in the arid and semi-arid areas of mainland China. Over-irrigation, over-grazing and deforestation in this area in the past have led to some serious ecological problems. Irrigation uses more than 70% of water resources available in this area and agriculture in this area is not sustainable anymore if one does not change the practice of water usage (the story is more detailed in our recent review, Kang et al. 2008, Int J Sust Devel World Ecol). Our new irrigation methods (largely the temporal and spatial deficit irrigations) have produced some very promising results and can save up to 50% of irrigated water and maintain the same yield. A small fraction of water saved from irrigation will mean a substantial amount of water that can be used for ecological maintenance. As a result of our effect in water-saving and deficit irrigation, I have been featured by Nature as one of ‘Five Crop Researchers Who Could Change the World’ (Nature 456, 563-568). This is a recognition to our effort in facing one of the major challenges to food security globally.

Another aspect of my applied research focuses on the grain filling. I started working on grain filling about ten years ago when I was working on the early senescence problem in wheat if irrigation was curtailed after flowering. Such early senescence induced by less irrigation may not be a problem if plants stay green for too long and pre-stored carbon is not fully used for grain filling. We have identified a slow grain filling problem in rice and wheat that is associated with an unfavorable delay of whole plant senescence. Monocarpic plants such as rice and wheat need the initiation of whole plant senescence so that stored carbohydrates in stems and leaf sheaths can be remobilized and transferred to their grains. Delayed whole plant senescence can lead to poorly filled grains and unused carbohydrate in straws. We found that a controlled soil drying during middle and late grain filling stage can greatly promote the whole plant senescence and food remobilization. The gain from a better utilization of pre-stored food outweighs the possible loss due to a shortened grain filling period (Tansley Review of New Phytologist, Yang and Zhang 2006).