Sarquis J I, Jordan W R, Morgan P W
Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843-2474.
Plant Physiol. 1992 Dec;100(4):2106-8. doi: 10.1104/pp.100.4.2106.
Maize (Zea mays) seedlings were exposed to elevated atmospheric pressures while growing in moist sand in open plastic envelopes to evaluate the effects of directly applied atmospheric pressure on ethylene production and root growth. Effects were evaluated after 24 h. The threshold pressures necessary to promote ethylene production and decrease root elongation were about 600 and 400 kPa, respectively. Direct atmospheric pressure, at levels up to 300 kPa, mimicked the control decrease in root diameter and increased diameter only slightly at 500 to 1200 kPa. In contrast, in previous work it was shown that physical impedance resulting from compression of the growth medium by external application of 100 kPa increased the ethylene production rate 4-fold and the root diameter 7-fold while reducing elongation 75% in 10 h. The relative insensitivity of roots to direct atmospheric pressure suggests that they perceive physical impedance, achieved experimentally by compressing the growth medium, via a surface mechanism rather than via a pressure-sensing mechanism.
将玉米（Zea mays）幼苗种植在开放塑料封套中的潮湿沙子里时，使其暴露于升高的大气压力下，以评估直接施加的大气压力对乙烯产生和根系生长的影响。24小时后评估效果。促进乙烯产生和降低根伸长所需的阈值压力分别约为600 kPa和400 kPa。高达300 kPa的直接大气压力模拟了对照中根直径的减小，而在500至1200 kPa时直径仅略有增加。相比之下，在先前的研究中表明，通过外部施加100 kPa对生长培养基进行压缩所产生的物理阻抗，在10小时内使乙烯产生速率提高了4倍，根直径增加了7倍，同时根伸长降低了75%。根系对直接大气压力的相对不敏感性表明，它们通过一种表面机制而非压力传感机制感知通过压缩生长培养基在实验中实现的物理阻抗。
