TITLE:
Dry Weight Accumulation, Root Plasticity, and Stomatal Conductance in Rice (Oryza sativa L.) Varieties under Drought Stress and Re-Watering Conditions
AUTHORS:
Doan Cong Dien, Takeo Yamakawa, Toshihiro Mochizuki, Aung Zaw Htwe
KEYWORDS:
Drought Tolerance, Recovery Ability, Re-Watering, Rice, Root Morphology
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.12,
November
28,
2017
ABSTRACT: Drought is one of the main factors limiting rice (Oryza sativa L.) productivity and has become an increasingly severe problem
in many regions worldwide. Establishing breeding programs to develop new drought-tolerant
varieties requires an understanding of the effect of drought on rice plants and
the mechanisms of drought tolerance in rice. We 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. 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. 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.