托福阅读之植物细胞组成

托福阅读之植物细胞组成。托福 阅读对大陆考生来说，是最容易拿分的题目，不过，要想获得高分，还需要在日常备考中进行不断的托福阅读练习。下面，为您提供托福阅读题材之“ 植物细胞组成”，大家可以在答题的过程中注意分析托福阅读段的易考点。

The cells of a plant'are organized into three tissue systems: dermal,vascular, and ground tissue. Each tissue system is continuous throughout theplant's body. The specific characteristics of each tissue, however, are different in the different organs ofthe plant.

The dermal tissue system is the "skin" of the plant. The dermal system, or epidermis,is a single layer of cells covering the entire body of the plant. The mailn function of the epidermis is to protect the plant. The epidermis also has specialized characteristics for the particular organs it covers. For example, the epidermis ofleaves and stems has a waxy coating that helps the plant conserve water, and the epidermal cells near the tips of the　plant's roots help the plant absorb water and nutrients from the soil.

The second tissue system-the vascular system-is the transportation system for water and nutrients. Vascular tissue also helps to support the plant's structure. The third system- the ground tissue-makes up the bulk of a plant, filling all of the spaces between the dermal and vascular tissue systems. Ground tissue functions in photosynthesis, storage, and support.