Marchesini Victoria A, Yin Chuanhua, Colmer Timothy D, Veneklaas Erik J
School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Key Laboratory of Oasis Ecology and Desert Environment, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
Funct Plant Biol. 2014 Dec;41(12):1230-1238. doi: 10.1071/FP14108.
Succulent halophytes of the genus Tecticornia are dominant in salt marshes of inland lakes of Australia. We assessed the drought responses of a C4 species, Tecticornia indica subsp. bidens (Nees) K.A.Sheph. & Paul G.Wilson, and two C3 species, Tecticornia auriculata Paul G.Wilson (K.A.Sheph. & Paul G.Wilson) and Tecticornia medusa (K.A.Sheph. & S.J.van Leeuwen) that occur in the Fortescue Marsh, north-west Australia. In a glasshouse experiment, the three species were grown individually and in different combinations, with varying number of plants per pot to achieve comparable dry-down rates among pots. Prior to the imposition of drought (by withholding water) the three species showed differences in dry mass and physiological variables. As the soil dried out, the three species showed similar reductions of transpiration, osmotic potential and photochemical efficiency. Shoot growth was depressed more than root growth. Tissue water loss from portions of the succulent shoots accounted for ~30% of transpiration during severe drought stress. There was no osmotic adjustment. Shoot tissue concentrations of Na+ and Cl- tended to increase during drought, and those of K+ decreased; however, these changes were not always statistically significant. Chlorophyll concentration decreased but betacyanin concentration increased. Despite occupying distinct positions in a water and salinity gradient, the three Tecticornia species had remarkably similar responses to soil water deficit.
盐节木属多汁盐生植物在澳大利亚内陆湖泊的盐沼中占主导地位。我们评估了一种C4物种印度盐节木亚种双齿盐节木（Nees）K.A.Sheph. & Paul G.Wilson，以及两种C3物种耳状盐节木Paul G.Wilson（K.A.Sheph. & Paul G.Wilson）和水母盐节木（K.A.Sheph. & S.J.van Leeuwen）在澳大利亚西北部福特斯库沼泽地的干旱响应。在温室实验中，这三个物种单独种植或以不同组合种植，每个花盆中的植株数量不同，以实现各花盆间可比的干燥速率。在施加干旱（通过停水）之前，这三个物种在干重和生理变量上存在差异。随着土壤变干，这三个物种的蒸腾作用、渗透势和光化学效率都出现了类似程度的降低。地上部生长受到的抑制比根部生长更大。在严重干旱胁迫期间，多汁地上部的组织水分损失占蒸腾作用的~30%。没有渗透调节现象。干旱期间地上部组织中的Na+和Cl-浓度趋于增加，而K+浓度降低；然而，这些变化并不总是具有统计学意义。叶绿素浓度降低，但甜菜色素浓度增加。尽管这三种盐节木在水分和盐度梯度中占据不同位置，但它们对土壤水分亏缺的响应却非常相似。
