Changes in Foliar Micromorphology of White Tea during Withering

Micromorphologicalcharacteristics of tea leaves during withering were examined to decipher thedynamic changes taken place in the process of white tea. Under a cold field emission scanning electron microscope, themorphological characteristics of the epidermal ornamentations, stomata, andtrichomes of the leaves of Camelliasinensis cv. Fudingdabaicha at 5 withering stages were examined.During withering, the initial wavy appearance of the epidermal ornamentationsgradually turned into wrinkled ridges as the process progressed. Whereas thetrichome ornamentations remained in the shape of long strips and the stomatalong ovate with heterosexual stomata (gland scales) throughout. Meanwhile, the length and width of outer and inner stomata as well as thestomatal size increased at first but declined afterward; the stomatal density rosefrom 286.44±20.41· mm^-2 to 423.78±35.14·mm^-2 positively correlating with the withering time; andthe trichome density also increased from 6.89±0.96·mm^-2 to 15.25±1.187·mm^-2 with time. On the other hand, no significant changes in the stomatal opening, thediameter, and the length or pattern of the trichomes were observed throughoutthe entire process.