Role of leaf structure in resistance to powdery mildew in water melon
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Authors
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Hui-Jun Zhang
Anhui Key Laboratory of Plant Resources and Biology, School of Life Science, Huaibei Normal University, Huaibei, Anhui
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Yu Ge
Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou,
Hainan
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Qiang Wang
Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi , 830091
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Jian-Nong Zhang
College of Agronomy, Gansu Agriculture University, Lanzhou, Gansu, People’s Republic of China
Abstract
Four varieties of water melon, exhibiting highly susceptible
to highly resistant response to powdery mildew, were
investigated for the role of wax content, stomata number,
stomata size, and thickness of palisade and spongy tissues
in resistance to powdery mildew.The results revealed: (1)
wax content of the resistant varieties was remarkably higher
than in the susceptible varieties; (2) stomata on the upper
surface of leaves in the resistant varieties was significantly
dense than in the susceptible ones, but stomata size in the
resistant varieties was just the opposite; and (3) the layer
of spongy tissue in the resistant varieties was thicker than
that in the susceptible genotypes, but the layer of palisade
tissue was thinner in the resistant genotypes compared to
the susceptible ones. Wax content, stomata number,
stomata size, and thickness of palisade and spongy tissues
could serve as a reliable indicator of resistance to powdery
mildew in melon.