Fu J, Huang B
Department of Horticulture, Forestry and Recreation Resources, Kansas State University, 66506, Manhattan, KS, USA
Environ Exp Bot. 2001 Apr;45(2):105-114. doi: 10.1016/s0098-8472(00)00084-8.
In natural environments, drought often occurs in surface soil while water is available for plant uptake deeper in the soil profile. The objective of the study was to examine the involvement of antioxidant metabolism and lipid peroxidation in the responses of two cool-season grasses to surface soil drying. Kentucky bluegrass (Poa pratensis L) and tall fescue (Festuca arundinacea Schreb.) were grown in split tubes, consisting of two sections (each 10 cm in diameter and 20 cm long). Grasses were subjected to three soil moisture regimes: (a) well-watered control: whole soil profile was watered; (b) surface drying: surface 20 cm of soil was dried by withholding irrigation and the lower 20 cm of soil was watered; (c) full drying: whole soil profile was dried. Surface drying had no effects on relative water content (RWC) and chlorophyll content (Chl) for both grasses and only slightly reduced shoot growth for tall fescue. Superoxide dismutase (SOD) activity increased, while catalase (CAT) and peroxidase (POD) activities remained unchanged during most periods of surface drying. Malondialdehyde (MDA) content was unaffected by surface drying for tall fescue, but increased initially and then decreased to the control level for Kentucky bluegrass. Under full drying, RWC, Chl content, and shoot dry weight decreased, but MDA content increased in both grasses; SOD and POD activities initially increased transiently and then decreased; CAT remained unchanged for 25 days and then decreased. These results suggested that both Kentucky bluegrass and tall fescue were capable of surviving surface soil drying. This capability could be related to increases in antioxidant activities, particularly SOD and CAT. However, full drying suppressed antioxidant activities and induced lipid peroxidation.
在自然环境中，干旱常常发生在表层土壤，而土壤剖面深处仍有植物可吸收利用的水分。本研究的目的是探究抗氧化代谢和脂质过氧化在两种冷季型草对表层土壤干燥响应中的作用。草地早熟禾（Poa pratensis L）和高羊茅（Festuca arundinacea Schreb.）种植于分体式试管中，试管由两部分组成（每部分直径10厘米，长20厘米）。对草施加三种土壤水分处理：（a）充分浇水对照：整个土壤剖面浇水；（b）表层干燥：通过停止灌溉使表层20厘米土壤干燥，下层20厘米土壤浇水；（c）完全干燥：整个土壤剖面干燥。表层干燥对两种草的相对含水量（RWC）和叶绿素含量（Chl）均无影响，仅略微降低了高羊茅地上部的生长。在表层干燥的大部分时期，超氧化物歧化酶（SOD）活性增加，而过氧化氢酶（CAT）和过氧化物酶（POD）活性保持不变。高羊茅的丙二醛（MDA）含量不受表层干燥影响，但草地早熟禾的MDA含量起初增加，随后降至对照水平。在完全干燥条件下，两种草的RWC、Chl含量和地上部干重均下降，但MDA含量增加；SOD和POD活性起初短暂增加，随后下降；CAT在25天内保持不变，随后下降。这些结果表明，草地早熟禾和高羊茅均能在表层土壤干燥条件下存活。这种能力可能与抗氧化活性的增加有关，尤其是SOD和CAT。然而，完全干燥抑制了抗氧化活性并诱导了脂质过氧化。
