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ROLE OF NITRATE
NUTRITION IN ALLEVIATION OF THE ADVERSE EFFECTS OF DROUGHT STRESS ON
MAIZE CULTIVARS: BIOMASS PRODUCTION AND ANTIOXIDATIVE
CAPACITY
LIXIN ZHANG1,2*,
KAI WANG1, XIFENG ZHANG1, LIXIA LU3,YUNFEI
LI3, MEI GAO1,2, CUIYUN WANG1,
JINJIANG HU1 AND ZONGSUO LIANG1,2
Abstract:
Optimal nitrogen
(N) nutrition has been shown to alleviate the negative effects of
drought stress (DS) on plants. The mechanisms of beneficial effect of
nitrogen form are not conclusive. In this study, the effects of
different ratios of nitrate (NO3-) to ammonium (NH4+)
nutrition on the growth and oxidative damage of two maize cultivar i.e.
Zhengdan 958 (ZD958) and Jundan 20 (JD20) were investigated under DS and
non-DS in nutrient solution. The activities of superoxide dismutase
(SOD) and catalase (CAT) increased, while that of peroxidase (POD)
remained unchanged in ZD958 with supplies of NO3-:
NH4+ ratios of either 100:0 or 50:50, while
in NO3-: NH4+ ratio of 0:100
in ZD958 and all NO3-: NH4+
ratios in JD20 all the enzymes showed decreased activities compared to
control. Furthermore, DS decreased biomass production, whereas increased
the contents of superoxide radical (O2•-) and
hydrogen peroxide (H2O2), along with an enhanced
accumulation of malondialdehyde (MDA) in the leaves of both cultivars.
The above effects were greater in JD20 than those in ZD958. An increased
ratio of NO3-: NH4+ in
culture solution increased the activities of SOD, POD and CAT while
decreased the production of O2•- and H2O2,
thereby diminishing MDA accumulation, and increasing biomass production
of drought-stressed plants of both cultivars. The above responses were
pronounced in ZD958 than those in JD20. This study demonstrated that
increased NO3--nutrition played a favored
anti-oxidative metabolic role, as compared with NH4+-nutrition,
in the plants thereby increasing tolerance to DS.
1College
of Life Sciences, Northwest A & F University, 712100, Yangling, Shaanxi,
P.R. China
2State
Key Laboratory of Soil Erosion and Dryland Farming, Institute of Soil
and Water Conservation, Chinese Academy of Sciences and Northwest A & F
University, 712100, Yangling, Shaanxi, P.R. China
3College
of Forestry, Northwest A & F University, 712100, Yangling, Shaanxi, P.R.
China
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