Dry Weight Accumulation, Root Plasticity, and Stomatal Conductance in Rice (Oryza sativa L.) Varieties under Drought Stress and Re-Watering Conditions
In rain-fed ecosystems, drought is the
major obstacle to rice production. Developing varieties resistant to drought is
considered a promising approach to increase rice yields in drought-prone environments.
However, this approach requires an understanding of rice plant responses to
drought and the mechanisms of drought tolerance in rice.
In this study, the
authors conducted a pot experiment to explore growth characteristics, root
plasticity, and stomatal conductance in six rice varieties (DA8, Malagkit Pirurutong,
Thierno Bande, Pate Blanc MN1, Kinandang Patong, and Moroberekan) in
response to different drought stress and re-watering conditions. The experiment
was performed in a greenhouse at the Faculty of Agriculture, Kyushu University,
Japan (33˚37'N, 130˚25'E; 3 m above sea level) in summer 2015. And the
experiment was conducted in a randomized complete block design with three
replicates.
The results
indicated that drought stress significantly depressed plant growth, root size,
and stomatal conductance in all experimental varieties. These negative effects
depended on both the variety and the severity of the drought stress treatment.
Under moderate drought stress (10 days after drought treatment), growth was
less influenced in roots than in shoots. In contrast, there was an opposite
trend under severe drought stress (15 days after drought treatment), with
growth being more severely affected in roots than in shoots. Rice plants
recovered from drought stress in terms of dry matter accumulation, root size,
and stomatal conductance after re-watering; however, the recovery pattern
differed among varieties.
In conclusion, DA8
exhibited the highest dry weight accumulation and root size (root length, root
surface area, root volume, fine root length, and thick root length) under
well-watered, drought stress, and re-watering conditions. Kinandang Patong
showed the highest recovery ability in dry matter accumulation, root length,
root surface area, and stomatal conductance after re-watering. Malagkit Pirurutong
expressed the poorest recovery ability in dry matter accumulation after
re-watering. These three varieties might be selected for further experiments
focusing on the mechanisms of drought tolerance and recovery ability in rice.
Article by Doan
Cong Dien, et al, from Kyushu University, Fukuoka, Japan.
Full access: http://mrw.so/1zXIgm
Image by Ahmad
Fuad Morad, from Flickr-cc.
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