Abstract: Taro (Colocasia esculenta) is a perennial bulbous plant of Araceae family. The leaf and petiole of taro have strong photosynthetic capacity and the structure and photosynthetic characteristics of leaves from different taro varieties are different. Two types of taro varieties ( Binglang′ and Xianghe′) that significantly differed in yield and architecture, were used as experimental materials in this study. By using resin semi-thin section, microstructural and ultrastructural observation and other experimental methods, the morphological and photosynthetic characteristics of taro leaf were systematically observed and analyzed. The photosynthetic rate, transpiration rate, intercellular CO2 concentration and stomatal conductance of the leaves of Xianghe′ were higher than those of the Binglang′. Compared with the Binglang′, Xianghe′ was larger in air cavity, denser in the number of pant stomata, and thicker in the palisade tissue. The surface of the Binglang′ leaves was rough and the stomas were small. The surface of the Xianghe′ leaves was smooth and the stomas were large. The above results showed that there were significant differences in morphological structure, photosynthetic characteristics between Xianghe′ and Binglang′. Binglang′ has more developed conducting tissue and Xianghe′ has smaller and denser air cavity, higher stomatal conductance, more rapidly transpiration rate and faster photosynthetic rate. The results could provide some information for the investigation of organ development and photosynthetic mechanism of taro.

Key words: taro, leaf, chloroplast, structure, photosynthetic characteristics