Difference in the glandular hair density in 10 flue-cured tobaccos

To investigate the difference in the glandular hair density in flue-cured tobacco varieties, the quantity and distribution of the glandular hairs of ten flue-cured tobacco varieties under the same cultivation conditions were determined using the optical microscope. The results showed that long handle glandular hairs were dominant with the range of 69.5-90.5%, which was much higher than short glandular hairs(9.5%-30.5%) in the flue-cured tobacco leaf glandular hairs. Long handle glandular hairs had the biggest impact on overall density of leaf blade glandular hairs, while short glandular hairs can reflect the varietal characteristics due to the stable quantity. The glandular trichome density between upper and lower epidermis was significantly different in 10 varieties(F=41.053,P0.01). The greater glandular trichome density on the lower epidermis can be more representative to the character of glandular trichome density with the variable coefficient being 0.14, which was in accordance with the whole epidermis glandular hairs density. Short glandular trichome density was greater on the upper epidermis than on the lower epidermis in all varieties except K326 and No. 7 Jiyan(F=6.466,P0.05). According to the average density of glandular hairs on the epidermis, the 10 varieties can be ordered as No.7 JiyanZhongyan 90K34687414Yunyan 858021NC82G28RG11K326. Although the glandular hairs density of flue-cured tobaccos was also affected by the environmental conditions, it can still be used as one of the indicators for screening flue-cured tobacco varieties in certain regions.