玉米叶表皮短细胞发育过程的形态特征及栓质细胞作用研究

采用大田试验，直接撕表皮或对叶片进行固定处理，结合单染、复染、荧光染色等多种细胞学显色方法，利用光学显微镜、荧光显微镜和扫描电子显微镜系统观察玉米叶表皮短细胞的发生时期、发育过程、分布规律以及形态结构特征，研究K⁺和H₂O₂在栓质细胞中的分布变化与表皮其它细胞中K⁺和H₂O₂的分布及气孔器开关的关系，为进一步挖掘短细胞的新功能提供细胞学依据。结果表明：（1）短细胞是同步发生在玉米多叶位新表皮组织形成过程中，所有植株从第7新生叶，大部分第6叶，极少数第5叶的基部同时开始发生短细胞，之后新生的高位叶也均发生短细胞，并随着叶位的升高叶片各部位短细胞密度均增大，所有植株的1~4叶（因不再生长）均无短细胞出现。（2）初期发育的叶表皮细胞进行不对称分裂，生成相互交替的长、短细胞，有的短表皮细胞横（垂直叶脉）分裂，形成栓质细胞和硅质细胞对；栓质细胞基部与叶肉细胞相邻，硅质细胞嵌在栓质细胞和表皮细胞间偏上。（3）有短细胞发生的叶片，宏观背面发亮且覆有蜡质层，微观表皮细胞的着色特性发生了变化；栓质细胞为面包形柱状细胞，硅质细胞为哑铃形扁细胞。（4）气孔器张开时，栓质细胞中没有K⁺和H₂O₂的积累；气孔器关闭时，栓质细胞中积累了大量的K⁺和H₂O₂，且栓质细胞中K⁺和H₂O₂的积累始终与副卫细胞中K⁺和H₂O₂的积累变化一致，而硅质细胞和长细胞没有K⁺和H₂O₂的积累。该研究确定了玉米叶表皮短细胞发生的时期；展示了其发育过程的形态学变化特征；发现栓质细胞中K⁺和H₂O₂的积累随气孔器开关呈周期性变化，且与副卫细胞中K⁺和H₂O₂的积累变化保持一致。

Morphological Characteristics Related to the Development Process of Short Cells and the Function of Cork Cells in Epidermis of Maize

Leaves epidermis of maize (Zea mays L.) grown in field conditions were torn,fixed,stained via combining the simple staining,counterstaining,fluorescence and other cytological chromogenic methods,and the generation time,developmental process,distribution,morphological characteristics of short cells in epidermis of maize were observed and the relationship of K⁺ and H₂O₂ distribution change of the cork cells with those in other epidermal cells and the stomatal switch were investigated through optical microscopy,fluorescence microscopy,and scanning electron microscopy.The study can provide a cell theoretical basis for further exploration in new functions of short cells.The results showed that:(1) short cells appeared when new epidermal tissue in the multi-leaf positions of maize formed,and the generation occurred in all plants from the seventh new leaf,the base of the sixth leaf of most plants and the fifth leaf of few plants,and appeared in all later grown leaves.Short cells density of different parts of leaf increased with leaf position elevating.No short cells were found in the four initial leaves of all plants (because of no further growth).(2) The initial leaf epidermal cells divided asymmetrically to produce alternating long and short cells.Some short epidermal cells divided horizontally (vertical to leaf vein) and formed cork and silica cells pairs.The cork cells base were adjacent to the mesophyll cells while the silica cells were embedded top between cork cells and epidermal cells.(3) The leaves with short cells,macrocosmically,the back of leaves was bright and covered with waxy layer,and the staining character of epidermal cells changed from a microcosmic perspective.The mature cork cells were bread-shaped columnar cells while the silica cells were dumbbell flat cells.(4) When stomata apparatus opened,no K⁺ or H₂O₂ was in cork cells;when stomata apparatus closed,a large amount of K⁺ and H₂O₂ accumulation can be found in cork cells.The K⁺ and H₂O₂ accumulation in cork cells was consistent with those in subsidiary cells,while no K⁺ or H₂O₂ accumulation in silica cells and long cells.The generation time of short cells in epidermis of maize was identified in the study,and the morphological variation characteristics of the developmental process was showed,we also found that the accumulation of K⁺ and H₂O₂ in cork cells changed periodically along with the stomatal switch was found,moreover,it was consistent with those in subsidiary cells.