三叶木通叶片解剖结构和生理特征对酸雨胁迫的响应和钛的缓解效应

Response of Anatomical Structure and Physiological Characteristics of Akebia trifoliata Leaves to Acid Rain Stress and Relieving Effect of Titanium

摘要:

为探讨三叶木通(Akebia trifoliata)对酸雨胁迫的响应机制和外源钛[Ti(SO₄)₂]对其耐酸性的影响，经模拟酸雨和外源钛处理，对叶片解剖结构和生理特征的变化进行了研究，并进行主成分分析和相关性分析。结果表明，与对照相比，模拟酸雨(T0)处理的叶片侧脉及表皮结构受损严重，叶主脉、主脉维管束、叶片和栅栏组织加厚，叶绿素含量显著降低，氧自由基产生速率、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均显著升高，而外源钛处理(T1⁓T3)均有效缓解叶侧脉和表皮的受损情况，并显著提高了叶绿素含量、SOD、POD和CAT活性，且氧自由基产生速率维持在较低水平。主成分分析表明，主脉、主脉维管束和叶厚等指标在三叶木通对酸雨胁迫逆境应答的机制中起关键作用。相关性分析表明，主脉维管束厚度、栅栏组织厚度、叶片组织结构紧密度、SOD、POD和CAT活性间呈极显著正相关关系。三叶木通幼苗通过改变叶片解剖结构、提高SOD、POD和CAT活性等方式来适应酸雨胁迫，且适当的Ti能够有效缓解酸雨胁迫造成的损伤，以0.2 mmol/L Ti效果最好。

Abstract:

To explore the response mechanism of Akebia trifoliata to acid rain stress and the effect of exogenous titanium [Ti(SO₄)₂] on its acid resistance, the changes in leaf anatomy and physiological characteristics were studied after simulated acid rain and exogenous titanium treatment, and the principal component analysis and correlation analysis were performed. The results showed that compared with the control, the lateral vein and epidermal structure of leaves were seriously damaged under simulated acid rain (T0) treatment, the main vein, main vein vascular bundle, leaf and palisade tissues were thickening, the chlorophyll content was significantly decreased, the oxygen free radical production rate, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly increased. Exogenous titanium treatments (T1-T3) effectively alleviated the damage of lateral vein and epidermal of leaves, significantly increased chlorophyll content, SOD, POD and CAT activities, and maintained a low rate of oxygen free radical production. Principal component analysis showed that main vein, vascular bundle and leaf thickness played a key role in response mechanism to acid rain stress. Correlation analysis showed that there were significantly positive correlations among vascular bundle thickness, palisade tissue thickness, leaf tissue structure tightness, activities of SOD, POD and CAT. Therefore, the seedlings of A. trifoliata could adapt to acid rain stress by changing the leaf anatomical structure and increasing the activities of SOD, POD and CAT. Appropriate Ti could effectively alleviate the damage caused by acid rain stress, and 0.2 mmol/L Ti had the best effect.