Stress physiology and metabolism in hybrid rice.III. Puddling and soil compaction regulate water status and internal metabolism during drought

ABSTRACT

Global water crisis, resulting from climate change, has become a prime concern for agricultural production. Our objectives were to determine the impact of puddling and soil compactionon drought tolerance, metabolism and antioxidative enzymes affecting growth of hybrid rice (Oryza sativa L.) under drought conditions. Accordingly, an experiment with three treatments, viz., puddled, compact, and control soils was conducted in pots using a completely randomized design with three replications. Both puddling and soil compaction reduced the adverse effects of drought on physiological traits. The positive effects of water stagnation because of physical modifications of soil, on drought tolerance traits and antioxidative enzymes during water stress, caused 1.2 to 2-fold increase in penetration resistance of physically modified soils and concomitantly reduced 3 to 6-fold water infiltration rate thereof. Puddling and soil compaction enabled plants maintain higher water potential than the control plants under drought conditions. Such plant conditions in puddled and compact soils caused low levels of proline and sugar, followed by higher levels of starch and protein than the control plants. Drought increased superoxide dismutase activity 2 to 2.4-fold, catalase 2 to 2.2-fold, ascorbate peroxidase 1.7 to 2-fold, and lipid peroxidase 2.3 to 3.6-fold. Adaptation to drought was apparently attributable to the cross-talk of drought event with plant metabolism, giving rise to the evolution of protective metabolic strategies. Thus, the increased water availability, through decreased water infiltration caused by puddling and soil compaction, is an important agronomic intervention for the maintenance of physiological activities andgrowth of rice under drought conditions.

KEYWORDS:

• Antioxidative enzymes
• chemical defense system
• infiltration
• puddling
• reactive oxygen species
• soil compaction
• soil moisture stress
• water stagnation

Acknowledgments

We owe our sincere thanks to late Ch. A. K. Singh, to Dr. F. D. Yadav, Head, Department of Botany for providing logistics and fruitful suggestions during these investigations and to Prof. N. S. Dharamwal of Dr. R. M. L. Avadh University, Faizabad for assisting in the determination of protein and enzyme activities. We also thank Dr. S. P. Giri, Plant Breeder, for providing seeds of hybrid rice cv. NDRH-2, Dr. T. P. S. Katiyar, Professor of Soil Physics for extending help in determining soil physics parameters and Dr. Amarpal Singh for statistical analyses of the data. Further, we extend our special thanks to the anonymous reviewers and Prof. M. S. Kang (Editor-in-Chief) who have greatly improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.