[Macroscopic and microscopic identification of Zhuang medicine Tetrastigma planicaule].

OBJECTIVE: To study the macroscopic and microscopic characteristics of Zhuang medicine Tetrastigma planicaule. METHODS: Macroscopic and microscopic identification were studied. RESULTS: The microscopic characteristics were significant. The root had more than 10 layers of cork cells arranging in line. The starch grain and calcium oxalate cluster crystals distributed in the phloem parenchymas, and mucilage cells scattered in the cortex of the stem. There were 8 vascular bundles in the vein of leaves. CONCLUSION: This study provides a scientific basis for the identification and utilizing of Tetrastigma planicaule.

Protease inhibitors decrease the resistance of Vitaceae to Plasmopara viticola.

Plasmopara viticola must successfully infect susceptible grapevine cultivars to complete its biological cycle. In resistant grapevine varieties, P. viticola is blocked by the activation of defense mechanisms; these defense mechanisms produce hypersensitive reactions, which are related to programmed cell death. In animals, programmed cell death is dependent on caspase activities. In plants, different caspase-like proteases assume the same functions. To examine the roles of caspase-like proteases in P. viticola-grapevine interactions, three varieties of grapevine with different levels of P. viticola resistance were chosen. These grapevine varieties were treated with either PMSF, a serine protease inhibitor, or E-64, a cysteine protease inhibitor. The development of the pathogen was followed microscopically, and the plant defense reactions were estimated through stilbene quantification. Both protease inhibitor treatments increased the infection rate in the resistant and immune varieties, diminished the production of toxic stilbenes and changed the level of the plants' susceptibility to the pathogen. In particular, after either protease treatment, the cultivar that was originally immune became resistant (hyphae and haustoria were observed), the resistant cultivar reached the level of a susceptible cultivar (sporulation was observed) and the susceptible cultivar became more sensitive (P. viticola colonized the entirety of the leaf mesophyll).

Structural and immunocytochemical characterization of the adhesive tendril of Virginia creeper (Parthenocissus quinquefolia [L.] Planch.).

The tendrils of Virginia creeper (Parthenocissus quinquefolia) do not coil around their supports. Rather, they adhere to supporting objects by flattening against the support surface and secreting an adhesive compound which firmly glues the tendril to the support. In this study, microscopic and immunocytochemical techniques were utilized to determine the nature of this adhesive. Following touch stimulation, epidermal cells of the tendril elongate toward the support substrate, becoming papillate in morphology. Following contact with the support surface, an adhesive is produced at the base of the papillate cells. The adhesive appears as a highly heterogeneous, raftlike structure and consists of pectinaceous, rhamnogalacturonan (RG) I-reactive components surrounding a callosic core. In addition, more mobile components, composed of arabinogalactans and mucilaginous pectins, intercalate both the support and the tendril, penetrating the tendril to the proximal ends of the papillate cells. Following adherence to the support, the anticlinal walls of the papillate cells are devoid of RG I side-chain reactivity, indicating that extensive debranching of RG I molecules has taken place. Furthermore, a large amount of RG I backbone reactivity was observed in the contact area. These results may indicate that the debranched RG I molecules diffuse into and permeate the contact region, forming an integral part of the adhesive compound. These results indicate that Virginia creeper adheres to objects by a composite adhesive structure consisting of debranched RG I, callose, and other, less-well characterized mucilaginous pectins and that this structure subsequently becomes lignified and very weather-resistant upon the ultimate senescence of the tendril.