Li Lu Lu, Jiang Xin Qiang, Liu Qing Chao, Liu Qing Hua, Sun Ying Kun, Wang Kui Ling
College of Landscape Architecture and Forestry, Qingdao Agricultural University, Qingdao 266109, Shandong, China.
Ying Yong Sheng Tai Xue Bao. 2016 Sep;27(9):2815-2822. doi: 10.13287/j.1001-9332.201609.032.
In this study, the adaptability of leaf shape, structure and stomata characteristics of Camellia sasanqua to temperature variation in natural process was investigated by field morphological observation, conventional paraffin section and scanning electron microscopy methods. The results showed that, as the temperature decreased, the leaf color changed from green to dark green, toge-ther with white and purple spots on the leaves. The relative conductivity and the percentage of wi-thered leaves increased initially and then decreased during this period. The highest percentages of relative conductivity and withered leaves in March 2015 were 56.0% and 25.4%, respectively. Different leaf tissue structure indexes, including middle vein thickness, leaf thickness, upper and lower epidermis thickness, upper and lower cuticle thickness, palisade tissue thickness, spongy tissue thickness, ratio of palisade tissue to spongy tissue, cell tense ratio and vein protuberant degree were also determined during the natural temperature change from September 2014 to April 2015. Gradually, these parameters increased initially and then decreased with the decrease of temperature except spongy ratio, which showed the opposite trend. These indicators above changed significantly in different months. Stomata length and width were not significantly changed in October 2014, December 2014 and March 2015, while the percentage of completely closed stomata was higher in March 2015, compared with other months. Taken together, we proposed that the improved adaptability of cold tolerance of C. sasanqua relies on the changes of leaf structure and stomatal closure.
本研究采用田间形态观察、常规石蜡切片和扫描电子显微镜方法，对自然过程中油茶（Camellia sasanqua）叶片形状、结构及气孔特征对温度变化的适应性进行了研究。结果表明，随着温度降低，叶片颜色从绿色变为深绿色，叶片上出现白色和紫色斑点。在此期间，相对电导率和枯叶率先升高后降低。2015年3月相对电导率和枯叶率的最高值分别为56.0%和25.4%。在2014年9月至2015年4月自然温度变化过程中，还测定了不同的叶片组织结构指标，包括中脉厚度、叶片厚度、上下表皮厚度、上下角质层厚度、栅栏组织厚度、海绵组织厚度、栅栏组织与海绵组织比值、细胞紧密度和叶脉突出度。除海绵组织比值呈相反趋势外，这些参数随温度降低先逐渐升高后降低。上述指标在不同月份变化显著。2014年10月、2014年12月和2015年3月气孔长度和宽度变化不显著，而2015年3月完全关闭气孔的比例高于其他月份。综上所述，我们认为油茶抗寒适应性的提高依赖于叶片结构的变化和气孔的关闭。
