判别分析法在描述叶温分布与植物水分状况关系上的应用

Applying the Method of the Distinquishing Analysis to Characterizing the Relationship Between the Temperature Dispersion on the Leaves Lower Surface and the Water Status in Sweet Potato Seedling

植物在水分胁迫条件下关闭气孔，以尽量减少水分耗散．但是气孔关闭不是整齐划一的行为，气孔的不均匀关闭会引起叶温的非均匀分布．本实验用了同精度下的生物多点温度仪、红外测温仪，对甘薯苗叶片下表面和上表面主脉周围与叶周边进行了同步温度测定，并用判别分析法对这些数据作了分析处理．结果表明：发生水分胁迫时，甘薯叶片下表面主脉周围的温度高于叶周边的温度，这两个温度的差值可以作为水分胁迫的指标：判断水分胁迫的温差阈值是0.8℃；对温度测定仪的精度要求是0.2℃．

The stomata would close when the plant suffered water stress so as to decrease the loss of water from the plant. The stomata do not altogether close at the same time. The none-uniform stomata movement results in none-uniform dispersion of temperature in the leaves. The temperature of the sweet potato leaves was measured in the upper surface and in the lower surface.The data taken from lower surface of the leaves can be as a morm for to distinquish how degree the plant suffered water stress.The sweet potato seeding must suffer water stress seriously when the range of the temperature between the leaves maine vein and the leaves margin is higher than 0.8℃.The precision of centigrade thermometer must be lower than 0.2℃ in the program measuring the leaves temperature.On the other hand,the data taken from upper surface of the leaves are of no avail.