An overview of the effects of phytotoxins on Phragmites australis in relation to die-back
An overview of the effects of phytotoxins on Phragmites australis in relation to die-back
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DOI：
10.1016/s0304-3770(01)00142-5
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发表时间：
2001-04-01
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
低分子量、挥发性、单羧酸和/或硫化物在沉积物中的积累，由(i)芦苇的地下部分和（ii）富营养化条件下产生的有机沉积物的腐烂产生，可能在芦苇枯死中起关键作用。在田间，在某些枯死地点和含有植物地下腐烂部分的沉积物中检测到其中一些植物毒素含量很高。枯死的症状包括成团习性、根和芽的发育迟缓和死亡、芽死亡、芽过早衰老、茎变弱、由于愈伤组织发育导致植物地下部分的通气受阻、维管系统内的阻塞、不定根的侧边和顶端区域的木质素化和落叶化以及根茎中淀粉含量较低。根茎系统对流通气不良也与茎碱中丙氨酸、γ -氨基丁酸和丝氨酸的比例较高有关，表明地下系统存在缺氧代谢。在实验室实验中，当植物受到各种单一植物毒素（如乙酸、丙酸、n-丁酸和异丁酸、n-己酸和硫化物）的处理时，植物出现了几乎所有枯死的生长、形态和解剖症状，这些毒素的浓度据报道为枯死部位和/或与植物地下腐烂部分相关。对于每一种单独的酸，浓度约为1 mM，在pH值为4.5时剧毒，但在pH值为6.0时相对无毒。然而，当使用五种酸的混合物（每种酸为1mm）时，即使pH值为6，混合物也被证明是有毒的。(C) 2001 Elsevier Science B.V.版权所有
The accumulation in sediments of the low molecular weight, volatile, monocarboxylic acids and/or sulphide, generated by the decay of (i) the underground parts of the reed and/or (ii) organic deposits produced under eutrophic conditions, may play a crucial part in Phragmites die-back. In the field high levels of some of these phytotoxins have been detected at certain die-back sites and in sediments containing the rotting underground parts of the plant.Symptoms of die-back include a clumped habit, stunting and death of roots and shoots, bud death, premature senescence of shoots, weakened stems, impeded aeration of the underground parts of the plant due to callus development, blockages within the vascular systems, lignification and suberisation of laterals and apical regions of adventitious roots and lower levels of starch in rhizomes. Poor convective aeration of the rhizome system has also been associated with higher proportions of alanine, gamma -amino butyric acid and serine in culm bases, indicating hypoxic metabolism in the underground system.In laboratory experiments plants developed almost all of the growth, morphological and anatomical symptoms of die-back when treated with various single phytotoxins, e.g. acetic, propionic, n- and iso-butyric and n-caproic acids and sulphide at concentrations reported for die-back sites and/or associated with the decaying underground parts of the plant. For each acid alone, a concentration of ca. 1 mM, was highly toxic at pH 4.5, but relatively non-toxic at pH 6.0. However, when a cocktail of the five acids was applied (where each acid was 1 mM) the mixture proved to be toxic even at pH 6. (C) 2001 Elsevier Science B.V. All rights reserved.