Abstract:

The water control experiment of potato was conducted in Shenyang Agricultural University. Potato flowering period and tuber expansion period were selected, and the mild drought (relative soil moisture during flowering period was 50% and that during tuber expansion period was 60%), moderate drought (relative soil moisture during flowering period was 40% and that during tuber expansion period was 50%) and severe drought (relative soil moisture during flowering period was 30% and that during tuber expansion period was 40%) and control (relative soil moisture during flowering period was 70% and that during tuber expansion period was 80%), rewatering treatment was carried out after 5 days of drought at all levels in each growth period, and the rewatering level was controlled to the control level. After the experiment, measure the activities of superoxide dismutase (SOD) and peroxidase (POD), proline and soluble sugar content, as well as chlorophyll a and total chlorophyll content in leaves, and the effects of drought stress and post-drought rewatering on potato leaf physiological characteristics were studied. The results showed that under light and moderate drought stress, the SOD and POD activities of leaves at flowering period were increased by 19.4%−32.3% and 20.8%−33.9% compared with the control, and the SOD and POD activities of leaves at tuber expansion period were increased by 17.4%−23.0% and 4.8%−25.3% compared with the control, respectively. The antioxidant enzyme activity of leaves decreased significantly in two critical periods. With the aggravation of drought stress, the content of osmotic regulatory substances in leaves increased sharply. Proline content was 2.7 times that of CK under severe drought stress in flowering period and twice that of CK under severe drought stress in tuber expansion period. The soluble sugar content of leaves at flowering period and tuber expansion period was 33.9%−44.4% and 17.8%−35.1% higher than that of control, respectively. After 5 days of drought stress, the content of proline in leaves decreased by 21.7%−59.1% compared with the drought treatment. However, after 5 days of severe drought in flowering period and moderate severe drought in tuber expansion period, the content of soluble sugar in leaves did not change significantly. Under drought stress, the contents of chlorophyll a and total chlorophyll at flowering period decreased by 12.8%−33.0% and 14.0%−36.9% compared with the control, and the contents of chlorophyll a and total chlorophyll at tuber expansion period decreased by 10.4%−15.2% and 12.0%−14.7% compared with the control, respectively. The contents of chlorophyll a and total chlorophyll in leaves increased by 10.9%−23.0% and 11.5%−15.1%, respectively, compared with that under drought treatment. Rehydration in time after drought could alleviate the damage caused by drought stress to a certain extent.

Key words: Potato, Drought stress, Rehydration after drought, Physiological characteristics