Abstract:

The paper aims to clarify the problem that watermelon fruit is difficult to expand normally under low light stress. Watermelon variety ‘Sumi 8’ was used as test material to study the effects of low light on watermelon plant growth and fruit development through field shading simulated low light stress. The results showed that the effect of low light on watermelon plant growth existed from the beginning of shading treatment; 3-15 days after pollination was the rapid expansion period of watermelon fruit, which was also the key period of weak light affecting watermelon fruit expansion. Low light could significantly reduce the plant height, stem diameter, leaf number and leaf size, and could significantly inhibit the accumulation of dry and fresh matter and the photosynthesis. Low light seriously affected the size and number of watermelon pulp cells, restricted the nuclear replication of watermelon fruit, and then affected the normal expansion of watermelon fruit. This study provides a scientific basis for the research and application of light environment management and low light resistance cultivation techniques for watermelon.

Key words: low light, watermelon, plant growth, fruit development, dynamic study