Abstract:

The drought resistance response and physiological mechanism of potato under drought stress were studied by exploring the botanical characters, physiological indexes and microscopic indexes of potato under different soil water content conditions. Two potato varieties of ‘Qingshu 9’ and ‘Minshu 1’ were used as materials. The optimum moisture content of soil in T₀ (CK) (70%-75% relative soil water content) was taken as the control, and other treatments were T₁ (55%-60%), T₂ (40%-45%), T₃ (25%-30%) and T₄ (no watering after emergence). The botanical characters, physiological indexes and microscopic indexes of potato plant were analyzed respectively. The results show that water stress has significant effects on phenotypic traits (plant height, stem diameter, fresh weight of aboveground part, dry weight of aboveground part, leaf area, root fresh weight, root dry weight and root length) of the two potato varieties, the measured values of the above botanical characters of ‘Qingshu 9’ and ‘Minshu 1’ have a decreasing tendency with the decrease of soil water content, the plant height, fresh weight of aboveground part, dry weight of aboveground part, root fresh weight, root dry weight and root length of ‘Qingshu 9’ are all higher than those of ‘Minshu 1’. The analysis of physiological indexes shows that under T₂-T₄ treatments, the contents of proline, malondialdehyde and superoxide dismutase in potato are significantly different from those of control T₀ (P<0.01). The microscopic index analysis shows that the upper epidermal thickness, lower epidermal thickness, palisade tissue thickness, sponge tissue thickness and grid-sea ratio of the leaves are all affected by water stress. The experiment could provide a theoretical basis for drought-resistant cultivation and breeding of potato.

Key words: potato, drought stress, biological traits, physiology and biochemistry, microstructure