红树植物桐花树、秋茄的有机酸类根系分泌物组成及含量

Composition and contents of organic acids in root exudates of mangrove Aegiceras corniculatum and Kandelia candel

红树植物对其林内生物包括微藻起着化感控制作用,化感作用与其根系分泌物密切相关.采用溶液培收集法收集桐花树(Aegiceras corniculatum,Ac)、秋茄(Kandelia candel,Kc)根泌物的水培液,用GC-MS和HPLC对其中的羧酸类的含量和组成进行定性和定量分析.结果表明,桐花树根泌物中含有草酸、壬二酸、琥珀酸、己二酸、乙酰丙酸、苹果酸共6种多元羧酸以及月桂酸1种饱和脂肪酸;秋茄根泌物中含有草酸、壬二酸、己二酸、乙酰丙酸共4种多元羧酸、月桂酸以及氢化肉桂酸1种酚酸.其中壬二酸、己二酸和乙酰丙酸在红树植物根泌物中为初次发现.草酸、壬二酸含量相对最高.桐花树、秋茄根泌物中草酸浓度分别为1.52 mg L-1和2.39 mg L-1,壬二酸浓度分别为12.98μg L-1和10.60μg L-1.羧酸含量定量分析对了解红树植物的化感作用具有重要意义.

Mangrove plants play an important allelopathic control effect on the forest organisms including microalgae. Such allelopathy is closely related with its root exudates（REs）. Since the research about organic acids in REs is in its initial stage, this study was focused on the components and contents of carboxylic acids in organic acids. The root hydroponic liquids were collected by solution culture method for two mangrove plants Aegiceras corniculatum and Kandelia candel. The carboxylic acids were qualitatively analyzed by GC-MS and quantitatively by HPLC. In the end, oxalic acid, azelaic acid, succinic acid, levulinic acid, adipic acid, malic acid and lauric acid were identified in REs of A. corniculatum, while oxalic acid, azelaic acid, levulinic acid, adipic acid, a fatty acid, lauric acid and 3-phenylpropionic acid were identified in REs of K. candel. This study was the first to find in mangrove REs azelaic acid, levulinic acid and adipic acid. Oxalic acid and azelaic acid were the major acids with the highest contents, with the concentration of oxalic acid 1.52 mg L-1 and 2.39 mg L-1 respectively in A. corniculatum and K. candel, and the concentration of azelaic acid 12.98 μg L-1and 10.60 μg L-1, respectively, in A. corniculatum and K. candel. The quantitative analysis of organic acids in REs is important for understanding the allelopathy of mangrove plants.