弱光对西瓜植株生长及果实发育的影响

为明确弱光下西瓜果实难以正常膨大的问题，以西瓜‘苏蜜8号’为试材，通过田间遮阴模拟弱光试验，研究弱光对西瓜植株生长、果实发育的影响。结果表明，弱光对西瓜植株生长的影响从遮光处理开始就一直存在；授粉后的3~15天为西瓜果实快速膨大期，也是弱光影响西瓜果实膨大的关键时期。弱光能显著降低植株的株高、茎粗、叶数和叶大小，并能显著抑制植株光合作用和干鲜物质的积累。弱光使西瓜果肉细胞变小，数目变少；抑制西瓜果肉的细胞核内复制，进而影响西瓜果实的正常膨大。本研究可为西瓜栽培光环境管理和抗弱光栽培技术的研究及应用提供科学依据。

Effects of Low Light on Plant Growth and Fruit Development of Watermelon

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.