茶树种质资源花器官微形态特征观察

【目的】对不同茶树种质资源花器官的微形态特征进行观察与分析，为种质资源鉴定评价提供参考依据。【方法】利用真空冷冻干燥和冷场发射扫描电镜技术，对11份茶树花器官的花柄、花托、萼片、花瓣、子房、花柱、柱头和花丝的表皮纹饰、气孔和茸毛纹饰等微形态特征进行系统观察，并进行变异系数和主坐标分析。【结果】茶树花柄和花托的表皮纹饰较相似，为细长条纹形，且在部分种质的花柄和花托上发现茸毛和气孔；萼片的内表皮光滑，可分为表皮细胞凹凸不平、凹陷和饱满3种类型，在其表面具平滑型茸毛；萼片外表皮光滑具条纹纹饰，在其表面分布着无规则气孔器且不同茶树种质气孔器特征不同；花瓣表皮细胞形状主要为不规则形、五边形、六边形和近圆形，其表皮分布着波状、条纹状、辐射状等纹饰；花丝表皮细胞为不规则多边形，排列紧密，具波状、丝状、条状的表皮纹饰，气孔主要分布在花丝的中下部；花柱表皮细胞排列整齐，其细胞形状可分为梭形、长条纹形和多边形3种类型；子房壁表皮细胞凹凸程度不同，满被平滑型茸毛。对参试茶树种质花器官的全部气孔数量性状进行测量统计，花柄气孔器大小为142.99~431.66μm2，气孔开度为0.19~0.92；花托气孔器大小为201.48~642.17μm2，气孔开度为0.26~0.62；萼片气孔器大小为219.74~563.32μm2，气孔开度为0.37~0.52；花瓣气孔器大小为401.80~1322.07μm2，气孔开度为0.38~0.66；花丝气孔器大小为257.90~706.74，气孔开度为0.32~0.73。对茶树花器官气孔数量性状变异分析，其变异系数平均值为18.5%；以40个微形态性状指标和16个微形态质量性状指标对11份种质进行主坐标分析，结果发现仅用质量性状时可有效区分种质。变异分析和主坐标分析表明茶树花器官的气孔相关数量性状种质内变异较大，而表面纹饰等质量性状具有较强的遗传稳定性。【结论】在茶树分类鉴定中，可适当考虑花器官的质量性状，并优先选择花器官的萼片、子房壁等纹饰特征作为识别不同茶树品种的依据。

Floral micromorphological trait of tea germplasm resources

【Objective】The microform of different tea floral structures was observed and analyzed, which would provide reference for the identification and utilization of tea tree germplasm.【Method】The vacuum freeze drying and field emission scanning electron microscopy(FE-SEM) observations were applied to investigate floral micromorphological traits of 11 tea, Camellia sinensis(L.) O. Kuntze, germplasms, and the coefficient of variation and principal coordinates were analyzed. The epidermal micromorphological traits(epidermises ornamentation, stomata and trichome ornamentation) of tea floral organs, such as peduncles, receptacles, sepal, petal, ovary, style, stigma and filament, were reported and analyzed.【Result】The peduncle and receptacle epidermises were similar in stripe shape. And trichomes and stomata were found in some germplasms. The inner epidermises of tea sepals were smooth, and could be divided into three types:uneven, concave and plump epidermal cells. There were smooth trichomes on the inner epidermises of the sepals. The outer epidermises of sepals were smooth and striated. There were irregular stomata on the surface, and different tea germplasms had different stomatal characteristics. The shapes of petal epidermal cells could be divided into four types:irregular, pentagon, hexagon and nearly round. On the petal epidermises, the wavy, striate and radial ornamentation were distributed. The filament epidermal cells were irregular polygons with stomates. The epidermises were closely arranged with wavy, filiform and striped epidermal ornamentation. Stomata were distributed in the middle and lower segments of filament. The epidermal cells of styles were neatly arranged, and the cell shapes could be divided into three types:fusiform, elongated and polygonal. The epidermal cells of ovary were different in the degree of smoothness, and were covered with smooth type trichomes. The stomatal quantitative characters in flower organs of tea germplasm were measured, the peduncle stomach size were 142.99-431.66μm2, and the stomatal aperture were 0.19-0.92. The receptacles stomach size were 201.48-642.17μm2, and the stomatal aperture were 0.26-0.62. The sepal stomach size were 219.74-563.32μm2, and the stomatal aperture were 0.37-0.52. The petal stomach size were 401.80-1322.07μm2, and the stomatal aperture were 0.38-0.66. The filament stomach size were 257.90-706.74μm2, and the stomatal aperture were 0.32-0.73. The variations of all stomatal quantitative characters were analyzed, and the average coefficient of variation was 18.5%. The principal coordinate analysis of 11 germplasms were carried out with all 40 micromorphological traits and 16 qualitative micromorphological traits, the results showed that only the quality traits could be used to distinguish the germplasms. It indicated that the quantitative stomatal traits had large variations intro-germplasm, while qualitative traits had strong genetic stability.【Conclusion】In the classification and identification of tea plants, the quality characters of flower organs can be properly considered, and the ornamentation characteristics of sepals and ovary walls of flower organs can be preferentially selected as the basis for identifying different tea varieties.