Physiological roles for aerenchyma in phosphorus-stressed roots
Physiological roles for aerenchyma in phosphorus-stressed roots
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DOI：
10.1071/fp03046
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发表时间：
2003-01-01
影响因子：
3
通讯作者：
Lynch, JP
中科院分区：
文献类型：
--
作者：
Fan, MS;Zhu, JM;Lynch, JP
低磷诱导根皮层通气组织的形成。这种反应的适应意义是未知的。我们假设通气组织可能有助于低磷植物通过减少根系呼吸和磷的需求，从而增加土壤勘探的代谢效率。为了验证这一假设，我们调查了通气组织的形成，根呼吸和组织磷浓度在玉米和菜豆基因型响应磷的可用性和乙烯处理。基因型在形成通气组织的能力上存在很大差异。通气组织的形成不成比例地与根呼吸减少;根的横截面积为30%的通气组织有70%的呼吸比根没有通气组织。通气组织的形成也成比例地与降低的根磷浓度相关。通气组织形成的变化与根呼吸和磷浓度相关，无论这种变化是由遗传或乙烯或磷处理。通过测量完整玉米植株的全根呼吸，证实了孤立根的结果。我们的研究结果支持这一假设，通气组织的形成减少了呼吸和磷的需求，土壤勘探的根，因此，代表了一个有用的适应低磷可用性。
Low phosphorus availability induces the formation of cortical aerenchyma in roots. The adaptive significance of this response is unknown. We hypothesized that aerenchyma may be helpful to low-phosphorus plants by reducing root respiratory and phosphorus requirements, thereby increasing the metabolic efficiency of soil exploration. To test this hypothesis we investigated aerenchyma formation, root respiration and tissue phosphorus concentration in maize and common bean genotypes in response to phosphorus availability and ethylene treatments. Genotypes differed substantially in their ability to form aerenchyma in response to low phosphorus. Aerenchyma formation was disproportionately correlated with reduced root respiration; roots with 30% cross-sectional area as aerenchyma had 70% less respiration than roots without aerenchyma. Aerenchyma formation was also proportionally correlated with reduced root phosphorus concentration. Variation in aerenchyma formation was correlated with root respiration and phosphorus concentration, regardless of whether such variation was caused genetically or by ethylene or phosphorus treatments. Results with isolated roots were confirmed by measurement of whole root respiration of intact maize plants. Our results support the hypothesis that aerenchyma formation reduces the respiratory and phosphorus requirements of soil exploration by roots, and thus, represents a useful adaptation to low phosphorus availability.