摘要
使用CI-310型便携式光合作用测定系统对西葫芦银叶病叶片的光合生理进行了测定.结果表明:西葫芦感染银叶病后,其一日内不同时段的光合速率(Pn)都较正常叶明显下降,轻病叶下降幅度为5.6%～30.2%,重病叶下降幅度为21.7%～52.5%,并且不同处理Pn的最高峰期也不尽一致,正常叶的最高峰期为10点钟,轻病和重病叶的最高峰期均为8点钟.西葫芦轻、重银叶病病叶的气孔限制值(Ls)均较正常叶减少,轻病叶减少幅度为5.3%～23.5%,重病叶减少幅度为22.0%～58.8%.轻、重病叶和正常叶之间的气孔导度(Gs)、胞间CO2浓度(Ci)差异不明显,蒸腾速率(Tr)的变化无规律性.经测定,西葫芦轻、重病叶的叶绿素a、b及叶绿素总量都较正常叶减少,轻病叶叶绿素总量减少9.97%,重病叶叶绿素总量减少18.21%.西葫芦重病叶的鲜、干重较正常叶减少,而轻病叶的鲜、干重较正常叶增加.对西葫芦银叶病叶片的解剖学特征观察发现,正常叶上表皮细胞为扁平状,致密排列;而病叶上表皮细胞则变为球状,疏松排列,并且上表皮与栅栏细胞之间出现轻微的间隙.病叶上表皮厚度占叶片厚度的比例明显增加,栅栏组织厚度占叶片厚度的比例略有减少.
The photosynthetic-physiological and anatomical features of silvered leaves of summer squash （ Cucurbita pepo L. ） were determinated. It was found that the net photosynthetic rates （Pn） of partially and entirely silvered leaves decreased 5.6% -30.2% and 21.7% -52.5%, respectively, compared to that of healthy leaves at most times within each day of trials. The highest Pn peak took place at different times in varied leaves, at 10 a.m. for healthy, but at 8 a.m. for silvered leaves. The stomata limit value （Ls） of partially and entirely silvered leaves decreased 5.3% - 23.5% and 22.0% - 58.8%, respectively. The total chlorophyll and chlorophyll a, b contents also decreased in silvered leaves. However, the values of stomata conductance （Gs） and intercellular CO2concentration （Ci） were similar in healthy and silvered leaves. No regularity was observed between the variation trends of transpiration rate （Tr） of healthy and silvered leaves. Compared to that of healthy leaves, the fresh and dry weight of partially silvered leaves increased a little, whereas those of entirely silvered leaves decreased a little. For healthy leaves, it was also found that the space was enlarged slightly between the upper epidermis and the palisade cells in silvered leaves. The upper epidermal cells changed from fiat, dense arrangement into globular, thin and scattered arrangement. The proportion of the upper epidermis thickness to the whole leaf thickness increased obviously in silvered leaves, but that of the palisade tissue thickness to the whole leaf thickness decreased at a small degree.
出处
《植物病理学报》
CAS
CSCD
北大核心
2005年第4期327-332,共6页
Acta Phytopathologica Sinica
关键词
西葫芦
银叶病
叶片
光合生理
解剖特征
summer squash
squash silverleaf
blade
photosynthetic-physiology
anatomical features
