缺锌和 HCO3－处理对诸葛菜和油菜有机酸特征的影响

摘要

The characteristics of organic acids in plant organs (roots,stems and leaves),and root exudates of seedlings of Orychophragmus violaceus and Brassica napus were investigated under the stress of Zn deficiency and excessive bicarbonate by ion chromatography,the two plant species were hydroponically grown and cultured in four different treatments:+Zn0 (the treatment of adequate Zn and none HCO3 - ),+Zn10 (the treatment of adequate Zn and HCO3 - addition),-Zn0 (the treatment of Zn deficiency and none HCO3 -),and -Zn10 (the treatment of Zn defi-ciency and HCO3 - addition),respectively.The results were as follows:(1)The total content of organic acids in plant organs and root exudations of the two plant species were significantly increased under excessive bicarbonate treat-ment,particularly under the dual treatment of Zn deficiency and excessive bicarbonate conditions (- Zn10 treat-ment),the organic acids in organs and root exudates of O .violaceus were more sensitive than that of B .napus ,oxal-ic,citric and malic acids were the dominant organic acids in organs and root exudates of O .violaceus ,the content of these three organic acids took account for more than seventy five percent of the total content of organic acids in organs and root exudates of O .violaceus ;(2)The leave was the maln region of organic acids production of the two plant species,the content and the allocated proportion of organic acids decreased from aboveground parts (leaves and stems)to belowground parts;(3)The variation trends of organic acids contents of organs were identical with that of root exudates in O .violaceus and B .napus ,and the source of organic acids in leaves of the two plant species was de-rived from the processes of dark respiration and photorespiration,while the source of organic acids in other organs such as stems and roots,as well as the source of organic acids in root exudates were come from the process of dark respiration;(4)The adaptability to the environment of low Zn and excessive HCO3 - of O .violaceus was higher than that of B .napus ,which provided evidences for the adaptability to karst environment of O .violaceus ,and ecological restoration in environments with low Zn and excessive HCO3 - ,such as a karst area.%以诸葛菜和油菜为材料，水培环境下设置4个不同的缺锌和碳酸氢根离子胁迫处理，分别为＋Zn0(含 Zn 且不加 HCO 3－的处理组)，＋Zn10(含 Zn 且加10 mmol•L-1 HCO 3－的处理组)，－Zn0(缺 Zn 且不加HCO 3－的处理组)和－Zn10(缺 Zn 且加10 mmol•L-1 HCO 3－的处理组)，利用离子色谱法分析了4个处理的两种植物幼苗器官(根、茎、叶)及根系分泌物中的有机酸特征。结果表明：(1)高浓度碳酸氢根离子处理显著增加了两种植物器官及根系分泌的有机酸总量，尤其是在缺锌和高浓度碳酸氢根离子双重胁迫下(－Zn10处理)，诸葛菜器官和根系分泌的有机酸比油菜更敏感，草酸、柠檬酸和苹果酸是诸葛菜器官和根系分泌物中的优势酸，这三种有机酸的含量分别占其有机酸总量的75％及以上；(2)叶片是两种植物有机酸产生的主要器官，有机酸的含量和分配比例从地上部分(叶和茎)到地下部分(根)减少；(3)两种植物器官和根系分泌物中的有机酸变化趋势一致，叶片中有机酸主要来源于暗呼吸过程和光呼吸过程，其他器官和根系分泌物中的有机酸主要来源于暗呼吸过程；(4)诸葛菜对缺锌和高浓度碳酸氢根离子的适应能力强于油菜，为诸葛菜的喀斯特适生性和低锌和高浓度碳酸氢根离子环境(如喀斯特环境)的生态修复提供了理论依据。