葡萄叶片齿尖上表皮气孔形态及发育特征

Morphology and Development of Adaxial Stomata on Tooth-tips of Grape Leaves

用光学显微镜对葡萄叶片齿尖上表皮气孔的形态、发育、结构进行了观察。叶片齿尖无表皮毛覆盖，上、下表皮都具有高密度的气孔分布。上表皮气孔位置下陷，无周缘角质条纹，外观呈‘面包围’形，典型的气孔与其旁边体形较小的气孔之间无特定的排列规律，它们的分化及成熟早于叶片中部下表皮气孔；齿尖下表皮气孔的形态特征与齿尖上表皮气孔相似；叶片中部下表皮存在典型的由气孔及其周围体形较小的气孔形成的气孔群。两类气孔分两批发育。典型的气孔突出表皮，具明显的周缘角质条纹，发育早于较小的气孔。这类气孔与表皮平面平齐或稍凹陷，周绿角质条纹不明显。叶片中部下表皮气孔的气孔下腔较大，齿尖上、下表皮气孔与叶片中部下表皮气孔无明显的结构差异。

Morphology and development of adaxial stomata on tooth tips of grape leaves were observed with light microscope and scanning electron microscope. It was found that no hairs on tooth tips, yet high density of stomata were observed on both upper.and lower epidermal surfaces. The appearance of adaxial stomata was relatively roundish without distinct cuticle ridges. Their level was lower than that of epidermal cells. Though the size was different, there was no sepecific rule for their distribution. Abaxial stomata on tooth tips were similar to adaxial ones on morphological and developmental aspects. Typical stoma clusters were existed on the lower epidermis of the middle part of grape leaves. They were consisted of the central 'larger' stoma and satellited 'smaller' stomata. The 'lager' ones were developed earlier than the 'smaller' ones, but both of them developed later than adaxial stomata on tooth tips. The 'larger' stomata in stoma clusters protruded above the epidermal level,their out ledges and radiating striae were very obvious. Those 'smaller' ones were at the same level or a litter lower compared with adjacent epidermal. cells. Their out ledges and radiating striae were not so apparent. As for the structure no obvious differences were observed between adaxial and abaxial stomata of tooth tips, and also no difference when compared them with abaxial stomata on the middle part of leaves.