Effects of drought stress and rehydration on carbon and nitrogen translocation in potato tuber swelling stage
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DOI:10.7606/j.issn.1000-7601.2019.04.21
Key Words: drought stress  rehydration  tuber swelling period  carbon and nitrogen translocation  C/N
Author NameAffiliation
QIAO Huan-huan College of Life Science, Northwest A & F University, Yangling, Shaanxi 712100
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100 
LI Hong-bing State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100 
ZHENG Tai-bo The Institute of Yanan Agricultural Science and Technology, Yanan, Shaanxi 716000 
DENG Xi-ping State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100 
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Abstract:
      To explore the physiological mechanism of carbon and nitrogen transport in potato tuber swelling stage to the drought stress and rehydration treatment, using potted plant experiment to study the changes of carbohydrates, nitrogen assimilates, and enzyme activity in potato leaves and tubers during drought stress and rehydration after drought. The results indicated that the activity of sucrose phosphate synthase (SPS) in potato leaves increased by 54.9%, and the contents of soluble sugar and sucrose increased by 84% and 25%, respectively during drought stress; the content of sucrose and starch in tuber decreased by 25% and 11.8%, respectively. After rehydration, the content of soluble sugar in leaves changed slightly, and the activity of SPS in leaves remained high; the sucrose synthase (SS) activity in tubers decreased by 6.25%, sucrose and starch content increased by 21.8% and 29.8%, respectively. Under drought stress, the activity of nitrate reductase (NR) in potato leaves decreased by 49.3%, while the activity of glutamine synthase (GS) was not significantly different from that of control. The content of free amino acid, soluble protein, and total nitrogen in potato leaves decreased by 29.4%, 38.4%, and 13%, respectively. The content of free amino acid and soluble protein in tubers increased by 16.8% and 270.9%, respectively. After rehydration, the activities of NR and GS in leaves were significantly higher than those in the control by 3.5% and 12.1%. The contents of free amino acids, soluble proteins, and total nitrogen in leaves remained low. The contents of free amino acids and soluble proteins in tubers increased by 24.6% and 178.4%, respectively, with no significant difference from those in the control. The results showed that drought stress significantly hindered the synthesis and transport of carbohydrates and nitrogen assimilates in potato leaves, and accumulated carbohydrates in potato leaves, but, drought stress promoted the transport of nitrogen to tubers, and decreased the ratio of carbon to nitrogen in tubers. The potato plants could quickly repair the damage caused by drought stress after rehydration, which showed that starch content in tubers increased and the ratio of carbon to nitrogen in tubers increased.
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