Experimental Station 'La Mayora' CSIC, Málaga, Spain.
Plant Biol (Stuttg). 2010 May 1;12(3):503-11. doi: 10.1111/j.1438-8677.2009.00239.x.
External characteristics of the leaf epidermis and their effects on behaviour of Aphis gossypii Glover were evaluated in two Cucumis melo L. genotypes, 'Bola de Oro' (aphid susceptible) and TGR-1551 (aphid resistant) in order to explore their role in the early rejection of TGR-1551 by this aphid. No differential effects of epicuticular waxes on aphid behaviour were observed. The type, distribution and number of trichomes on melon leaves were also studied. Pubescence in melon, measured as the number of non-glandular trichomes per cm(2), was not sufficient to prevent aphid settling. However, there was a high density of type I glandular trichomes on leaves of the aphid-resistant genotype. According to microscopic observations and stain testing, these trichomes store and secrete phenols and flavonoids. Free-choice tests were conducted to determine the effect of these glandular trichomes on A. gossypii preference, revealing that aphids reject leaf disks of TGR-1551 from the onset of the experiment. Additional experiments after removal of leaf type I glandular trichome exudates showed that A. gossypii preferred washed TGR-1551 leaf disks over unwashed disks, while this effect was not observed in experiments using washed and unwashed 'Bola de Oro' leaf disks. These results suggest that a high density of glandular trichomes and chemicals secreted by them deter A. gossypii and disturb aphid settling on TGR-1551.
为了探究甜瓜叶片表皮的外部特征及其对棉蚜行为的影响在甜瓜抗蚜品种 TGR-1551 和感蚜品种‘Bola de Oro’中的作用，我们评估了这两个甜瓜基因型叶片表皮的外部特征及其对棉蚜行为的影响，以探索其在早期排斥 TGR-1551 棉蚜中的作用。我们未观察到蜡质对棉蚜行为的差异影响。还研究了甜瓜叶片上的表皮毛的类型、分布和数量。甜瓜的绒毛，即每平方厘米非腺毛的数量，不足以防止蚜虫定殖。然而，在抗蚜品种的叶片上有高密度的 I 型腺毛。根据显微镜观察和染色试验，这些表皮毛储存并分泌酚类和类黄酮。进行了选择试验以确定这些腺毛对棉蚜偏好的影响，结果表明，棉蚜从实验开始就拒绝 TGR-1551 的叶片圆盘。去除叶片 I 型腺毛分泌物后的附加实验表明，棉蚜更喜欢清洗过的 TGR-1551 叶片圆盘而不是未清洗的圆盘，而在用清洗过和未清洗的‘Bola de Oro’叶片圆盘进行的实验中则未观察到这种效果。这些结果表明，高密度的腺毛及其分泌的化学物质可以阻止棉蚜并干扰其在 TGR-1551 上的定殖。
