石灰土壤中植物铁营养生理生化的研究进展

Physiological and Biochemical Characteristics of Plant Iron Nutrition in Calcareous Soil: Research Progress

为了阐明石灰土中植物缺铁失绿的生理生化机理,本研究总结了重碳酸盐改变土壤p H值,降低土壤中铁的可利用性,从而限制了植物对土壤中铁的吸收;另一方面,植物在重碳酸盐胁迫下,诱导植物根系产生一系列的生理生化反应响应低铁生境,包括植物根系分泌相关的物质或质子到根际土壤酸化土壤,诱导根系铁还原酶基因和铁转运体基因表达从而增强铁还原酶活性及铁吸收。针对石灰土壤中存在大量重碳酸盐的特殊性,未来应加强以下几个方面的研究,(1)重点研究重碳酸盐对铁在植物组织之间的长距离运输的影响,挖掘重碳酸盐影响铁转运的分子机制;(2)植物细胞内的铁蛋白基因表达是否受到重碳酸盐的影响,仍然需要开展相关的研究;(3)进一步研究土壤中的微生物与重碳酸盐在植物胁迫中的作用。

The aim is to elucidate the physiological and biochemical mechanism that iron deficiency induced chlorotic symptom of plant in calcareous soil. We summarized that the bicarbonate changed soil pH value and then reduced the iron availability in soil, so that it limited the iron uptake in plants. Additionally, the bicarbonate stress induced a series of physiological and biochemical reactions in roots in response to the low iron habitat, including the roots secreting relative substances or proton to the rhizosphere soil to acidify soil, inducing the expression of ferric reductase gene and iron transporter gene to enhance iron reduetase activity and iron uptake from soil. According to the characteristics of calcareous soil, the future research should be carried out on： （1） highlighting the effect of bicarbonate on iron transport from root to leaf to explain molecular mechanism of chlorotic symptom; （2） clarifying the effect of bicarbonate on the expression of ferritin gene in cell; （3） exploring the relationship between microorganisms and bicarbonate to reveal the characteristics of olant adaotation to calcareous soil.