水芹和旱芹营养器官结构和叶片光合特性的比较分析

Comparison and analysis of the nutritional organ structure and photosynthetic characters in cress and celery

以水芹品种‘南京八卦洲水芹’和旱芹品种‘六合黄心芹’为材料,采用盆栽的方法,对其营养器官结构和不同光照强度下叶片光合特性进行了比较研究。结果表明:水芹根系维管束比旱芹发达;水芹叶柄为中空结构,有较大的髓腔,而旱芹结构致密,无髓腔;旱芹叶片维管束和韧皮部细胞发达,木质部导管细胞数目较多,而水芹维管束相对不发达,木质部和韧皮部细胞较少。当光照强度为90μmol·m-2·s-1时,旱芹的净光合效率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)分别是水芹的1.45、1.81、1.49和1.69倍;当光照强度为270μmol·m-2·s-1时,旱芹的Pn、Gs、Ci和Tr分别是水芹的1.77、1.61、1.71和1.46倍。在一定光照强度范围内,旱芹和水芹的Pn与Gs、Tr呈正相关,与Ci呈负相关,并且旱芹的Pn要高于水芹。表明2种芹菜的光合特性与叶片的维管束、韧皮部、木质部导管相关。

Cress（ ＇ Nanjinghaguazhoushuiqin＇ ）and celery （ ＇ Liuhehuangxinqin＇ ）were selected to compare their structure of nutritional organ and photosynthetic characters under different light intensity. The results showed that root vascular bundles of cress were more sophisticated than those of celery. The structure of petiole in cress was hollow with big cavum medullare, while the structure was compact in celery without cavum medullare. There were more xylem cells ,better developed phloem cells and vascular bundles in celery than in cress. The net photosynthetic rate（ Pn ） , stomata1 conductance （ Gs ）, intercellular CO2 concentration （ Ci ） and transpiration rate （ Tr ） of celery were 1.45,1.81, 1. 49 and 1.69 times more than those of cress at 90 μmol·m^-2·s^-1 light intensity, and were 1.77,1.61, 1.71 and 1.46 times more than those of cress at 270 μmol·m^-2·s^-1 light intensity,respectively. Under certain light intensity,P,, of cress and celery was positively correlated with Gs and Tr and negatively correlated with Ci. Po of celery was higher than that of cress. The results proved that photosynthetic characters of the cress and celery were related with vascular bundles ,phloem and xylem of blade.