A CONVECTIVE THROUGH-FLOW OF GASES IN PHRAGMITES-AUSTRALIS (CAV) TRIN EX STEUD
A CONVECTIVE THROUGH-FLOW OF GASES IN PHRAGMITES-AUSTRALIS (CAV) TRIN EX STEUD
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DOI：
10.1016/0304-3770(91)90023-x
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发表时间：
1991-02-01
期刊：
影响因子：
1.8
通讯作者：
ARMSTRONG, W
中科院分区：
文献类型：
--
作者：
ARMSTRONG, J;ARMSTRONG, W
第一个直接证明气体在草中对流通过的证据是芦苇（Cav.）。指标。Steud交货。水流似乎是在活叶鞘和活茎节气孔区开始的。对流气体通过茎和地下根茎中的空气空间传播，并通过旧的折断的茎排出。在明亮的光线和低大气湿度下，对流特别迅速。因此，它应直接促进根茎通气，并通过增加根冠交界处的氧气状况，使氧气更大程度地扩散到根部。在田间记录了高达800 Pa的静压差和高达800 mm min-1的流速（流速为960 X 10(-6) m3 h-1）。这个机制看起来很复杂，但可能主要是基于湿度诱导的克努森扩散进入植物。光照、湿度、温度、气孔和可能的光合因子都参与其中；在夜间，对流非常缓慢。利用核孔膜“密封”加湿腔模拟了湿度诱导对流。
The first direct evidence of a convective through-flow of gases in a grass is reported for Phragmites australis (Cav.) Trin. ex Steud. The flow appears to be initiated in living leaf sheaths and in the living nodal stomatal regions of the culm. The convected gases are transmitted via air spaces in the culm and underground rhizome, and are vented via old broken culms. The convection is particularly rapid in bright light and at low atmospheric humidities. Consequently, it should cause direct enhancement of rhizome aeration and, by increasing the oxygen regime at the root-shoot junction, cause a greater diffusion of oxygen into the roots. Static pressure differentials up to 800 Pa and flow velocities of up to 800 mm min-1 per leafy shoot (flow rate, 960 X 10(-6) m3 h-1 per shoot) have been recorded in the field.The mechanism appears complex, but is probably based chiefly on humidity-induced Knudsen diffusion into the plant. In the light, humidity, temperature, stomatal and possibly photosynthetic factors are involved; at night, the convection is very much slower. The humidity-induced convection has been mimicked using nuclepore membranes "sealing" humidified chambers.