Department of Crop Science, Faculty of Agriculture, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
Molecules. 2013 May 21;18(5):5965-79. doi: 10.3390/molecules18055965.
The effect of foliar salicylic acid (SA) applications (10⁻³ and 10⁻⁵ M) on activities of nitrate reductase, guaiacol peroxidase (POD), superoxide dismutases (SOD), catalase (CAT) and proline enzymes and physiological parameters was evaluated in two ginger varieties (Halia Bentong and Halia Bara) under greenhouse conditions. In both varieties, tested treatments generally enhanced photosynthetic rate and total dry weight. Photosynthetic rate increases were generally accompanied by increased or unchanged stomatal conductance levels, although intercellular CO₂ concentrations of treated plants were typically lower than in controls. Lower SA concentrations were generally more effective in enhancing photosynthetic rate and plant growth. Exogenous application of SA increased antioxidant enzyme activities and proline content; the greatest responses were obtained in plants sprayed with 10⁻⁵ M SA, with significant increases observed in CAT (20.1%), POD (45.2%), SOD (44.1%) and proline (43.1%) activities. Increased CAT activity in leaves is naturally expected to increase photosynthetic efficiency and thus net photosynthesis by maintaining a constant CO₂ supply. Our results support the idea that low SA concentrations (10⁻⁵ M) may induce nitrite reductase synthesis by mobilizing intracellular NO³⁻ and can provide protection to nitrite reductase degradation in vivo in the absence of NO³⁻. Observed positive correlations among proline, SOD, CAT and POD activities in the studied varieties suggest that increased SOD activity was accompanied by increases in CAT and POD activities because of the high demands of H₂O₂ quenching.
在温室条件下,研究了叶面喷施水杨酸(SA)(10⁻³和 10⁻⁵ M)对两种生姜品种(Halia Bentong 和 Halia Bara)硝酸还原酶、愈创木酚过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和脯氨酸酶活性及生理参数的影响。在两种品种中,测试处理通常都能提高光合速率和总干重。光合速率的增加通常伴随着气孔导度水平的增加或不变,尽管处理植物的胞间 CO₂浓度通常低于对照。较低的 SA 浓度通常更有效地提高光合速率和植物生长。外源 SA 的应用增加了抗氧化酶活性和脯氨酸含量;用 10⁻⁵ M SA 喷雾处理的植物反应最大,CAT(20.1%)、POD(45.2%)、SOD(44.1%)和脯氨酸(43.1%)活性显著增加。叶片中 CAT 活性的增加自然可以通过维持恒定的 CO₂供应来提高光合效率,从而提高净光合作用。我们的结果支持这样一种观点,即低浓度的 SA(10⁻⁵ M)可以通过动员细胞内的 NO³⁻来诱导亚硝酸还原酶的合成,并在没有 NO³⁻的情况下为体内亚硝酸还原酶的降解提供保护。在所研究的品种中,脯氨酸、SOD、CAT 和 POD 活性之间存在正相关关系,这表明 SOD 活性的增加伴随着 CAT 和 POD 活性的增加,因为 H₂O₂淬灭的需求很高。