The response of rice roots and shoots and their causal relationships affecting yield under varying soil water condition are important related subjects of research. To understand the mechanism of response, studies were conducted using four water treatments: a) intermittent flooding through the vegetative stage (IF-V); b) intermittent flooding extended into the reproductive stage (IF-R); c) no standing water (NSW), maintaining soil at field capacity; and d) continuous flooding (CF) condition at the Asian Institute of Technology in Thailand.
It was observed that the senescence of lower leaf and flag leaf was delayed under IF-V compared to CF water condition. This delay was associated with higher root oxidizing activity (ROA) rate (50% higher than CF), higher root length density (RLD) (52% higher than CF), higher biomass production (14% higher than CF) along with higher grain yield (25% higher than CF). The plants grown under NSW conditions had better growth at later growth stage and better yield performance compared to IF-R because of higher nitrogen availability and higher uptake rate under NSW water conditions (73% higher N uptake). However, under CF water condition the nitrogen availability was not a limiting factor but due to decreased root activity rate the dry matter production and grain yield significantly reduced compared to IF-V water condition.
The results suggested that ROA and RLD are linked to shoot response and to dry matter production. A better understanding of the underlying mechanisms should assist in achieving improvements in crop productivity through improved crop management practices in water-limiting environment.
CEESAY, M. - REID, W.S. - FERNANDES, E.C.M. - UPHOFF, N. 2006. The effect of repeated soil wetting and drying on low land rice yield with System of Rice Intensification (SRI) methods. In International Journal of Agricultural Sustainability, vol. 4, 2006, no. 1, pp. 5-14. do i:10.1080/14735903.2006.9686007
GALLARDO, M. - TURNER, N.C. - LUDWIG, C. 1994. Water relations, gas exchange and abscisic acid content of Lupinus cosentinii leaves in response to drying different proportion of the root system. In Journal of Experimental Botany, vol. 45, 1994, no. 7, pp. 909-918. do i:10.1093/jxb/45.7.909
GEWIN, V. 2010. An underground revolution. In Nature, vol. 466, 2010, pp. 552-553.
KAR, S. - VARADE. S.B. - SUBR AMANYAM, T.K. - GHI LDAYAL, B.P. 1974. Nature and growth pattern of rice root system under submerged and unsaturated condition. In IL Riso (Italy), vol. 23, 1974, pp. 173-179.
MARKWELL, J. - OSTERMAN, J.C. - MITCHELL, J.L. 1995. Calibration of the Minolta SPAD-502 leaf chlorophyll meter. In Photosynthetic Research, vol. 46, 1995, no. 4, pp. 467-472.
McCAULEY, G.N. 1990. Sprinkler vs. flood irrigation in traditional rice production regions of southeast Texas. In Agronomy Journal, vol. 82, 1990, pp. 677-683. do i:10.2134/agronj1990.0002 1962008200040006x
MISHR A, A. - WHI TTEN, M. - KETELAAR, J.W. - SALOKHE, V.M. 2006. The system of rice intensification (SRI): A challenge for science, and an opportunity for farmer empowerment towards sustainable agriculture. In International Journal of Agricultural Sustainability, vol. 4, 2006, no. 3, pp. 193-212. do i:10.1080/14735903.2006.9684802
MISHR A, H.S. - RATHORE, T.R. - PANT, R.C. 1997. Root growth, water potential and yield of irrigated rice. In Irrigation Science, vol. 17, 1997, no. 2, pp. 69-75.
NEWELL, R.L. - WILHELM, W.W. 1987. Conservation tillage and irrigation effects on corn root development. In Agronomy Journal, vol. 79, 1987, pp. 160-165. do i:10.2134/agronj1987.0002 1962007900010033x
OSAKI, M. - SHI NANO, T. - MATSUMOTO, M. - ZHENG, T. - TADANO, T. 1997. A root-shoot interaction hypothesis for high productivity of field crops. In Soil Science & Plant Nutrition, vol. 43, 1997, pp. 1079-1084.
PROFFITT, A.P.B. - BERLINER, P.R. - OOSTERH UIS , D.M. 1985. A comparative study of root distribution and water extraction efficiency by wheat grown under high and low frequency irrigation. In Agronomy Journal, vol. 77, 1985, no. 5, pp. 655-662. do i:10.2134/agronj1985.00021962007700050001x
SAH, R.N. - MIKKELSEN, D.S. 1983. Availability and utilization of fertilizer nitrogen by rice under alternate flooding. In Plant and Soil, vol. 75, 1983, no. 2, pp. 221-226.
SATO, S. - UPHOFF, N. 2007. A review of on-farm evaluation of system of rice intensification (SRI) methods in eastern Indonesia. In CAB Review: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, vol. 2, 2007, pp. 1-12.
SKINNER, R.H. - HANASON, J.D. - BENJAMIN, J.G. 1998. Root distribution following spatial separation of water and nitrogen supply in furrow irrigated corn. In Plant and Soil, vol. 199, 1998, pp. 187-194.
SOEJIMA, H. - SUGIYAMA, T. - ISHIH ARA, K. 1995. Changes in the chlorophyll contents of leaves and in levels of cytokinins in root exudates during ripening of rice cultivars Nipponbare and Akenohoshi. In Plant Cell Physiology, vol. 36, 1995, pp. 1105-1114.
YANG, J. - ZHANG, J. - WANG, Z. - LIU, L. - ZHU, O. 2003. Post-anthesis water deficit enhance grain filling in two-line hybrid rice. In Crop Science, vol. 43, 2003, no. 6, pp. 2099-2108. do i:10.2135/cropsci2003.2099
ZHANG, X. - TAN, G. - HUANG, Y. 1994. Experimental Technology of Plant Physiology. Shenyang, China : Liaoning Science and Technology Press, 1994, pp. 51-75.