木贼类营养器官凯氏带类型的新观察

该研究用石蜡切片法比较观察了5种木贼科植物营养器官的内皮层及凯氏带,首次报道了2层内皮层及其凯氏带的形态特征及分布规律,并讨论各种类型的凯氏带及其与厚壁组织的协作防御机制。结果表明:(1)5种木贼的地下茎和根都只有1条凯氏带,其中4种木贼的地上茎有2条凯氏带。(2)木贼类营养器官具有3种凯氏带类型,即2层公共内皮层上各具有1条凯氏带、1层散生内皮层上的1条凯氏带、1层公共内皮层上的1条凯氏带。(3)木贼类地下茎和根都有发达的厚壁组织或致密的表皮。(4)问荆地上茎外侧内皮层具有复合内皮细胞。研究认为,木贼类植物凯氏带数量不能作为分类的依据;地下茎和根虽然只有1条凯氏带,但地下部分都有发达的厚壁组织或(和)与其紧密相连的表皮,推测厚壁组织或(和)表皮可能具有与凯氏带相同的功能;3种类型凯氏带的防御能力由强到弱依次是:2层公共内皮层上的凯氏带 1层散生内皮层上的凯氏带 1层公共内皮层上的凯氏带。

New Observations on the Types of Casparin Strip in the Vegetative Organs of Horsetails

In this test, the endodermis and Casparin strip of vegetative organs of five species of Equisetaceae were comparatively observed by paraffin section method. The morphological characteristics and distribution of two layers of endodermis and its Casparin strip were reported for the first time, and the various types of Casparin strip and their cooperative defense mechanisms with sclerenchyma were also discussed. The results showed that: (1) there was only one Casparin strip in the rhizomes and roots of five species of horsetail, and there were two Casparin strips in the aerial stems of four species of horsetail. (2) There were three types of Casparin strip in the vegetative organs of horsetails, namely, one Casparin strip on each of the two common endodermis, one Casparin strip on one scattered endodermis, and one Casparin strip on one common endodermis. (3) The rhizomes and roots of horsetails had developed sclerenchyma or dense epidermis. (4) There were complex endodermis cells in the outer endodermis of the aerial stem of Equisetum arvense L.. It was suggested that the number of Casparin strip of horsetails can not be used as a basis for classification. Although there was only one Casparin strip in the rhizomes and roots, there were developed sclerenchyma or (and) epidermis closely connected with them in the underground part. It is speculated that sclerenchyma or (and) epidermis may have the same function as Casparin strip. The defense ability of the three types of Casparin strip from strong to weak is as follows: Casparin strip on two common endodermis > Casparin strip on one scattered endodermis > Casparin strip on one common endodermis.