Poster: Root biology

Abs # 701: Dynamics of root and shoot interaction for submergence tolerance of rainfed lowland rice

Presenter:	Singh, Hari P, hpsingh@uga.edu
Authors	Singh, Hari P (A) (B)  Singh, Brija B (B)
Affiliations:	(A): Plant Genome Mapping Laboratory, University of Georgia, Athens, Georgia, U.S.A (B): Centre of Advanced Studies in Plant Physiology, N.D. University of Agriculture & Technology, Kumarganj, Faizabad, India
Web Site:	http://www.plantgenome.uga.edu/

Rice-based, lowland ecosystems, which are found in the humid and sub-humid tropics of South and Southeast Asia (Zeigler and Puckridge 1995), depend solely on monsoonal rainfall and runoff water from the catchment areas and constitutes about one fourth (approximately 40 million hectares) of the total rice area of the world, contributing 18 percent of the global rice supply (IRRI 1993). Submergence is one of the major constraints in rice production (Almeida et al, 2003).The adverse effects of flooding or submergence are multiple and complex. Most of the research done on the physiology and biochemistry of submerged rice were mainly concentrated on the shoots. However, work on roots which are equally important for growth and survival of rice plants as is shoots has largely been neglected. During complete submergence for longer days the root functions are inhibited or completely checked due to restricted oxygen supply to roots. The growth and development of plant is thus altered due to this inhibition and results in reduced crop yield through interference in water relations, mineral nutrition and hormone balance. Complete submergence (1, 3, and 6d.) of the rice plant adversely affected xylem sap flow rates, hydraulic conductivity, solute transport, and dry weight of root and shoot. Soluble sugars in root and shoot showed positive relationship to the extent of recovery of the damaged roots from submergence stress. The impact of healthy shoots has shown significant relevance in respect to the restoration of normal root functions at desubmergence and at recovery. Results form this study is expected to benefit the ongoing research of submergence tolerance physiology emphasizing the role of root functioning in relation to submergence tolerance of rainfed lowland rice.