香蕉对低pH和铝毒胁迫的响应

Response of Banana to Low pH and Aluminum Toxicity Stress

香蕉是世界重要的热带亚热带水果,在热带经济的发展中占有重要的地位。我国是世界香蕉重要生产国之一,总产量仅次于印度,位居世界第二。低pH和铝毒是香蕉生产中面临的重要限制因子,严重影响香蕉的产量和品质。明确低pH和铝毒胁迫对香蕉生长和养分吸收的影响,为调控酸性土壤提供重要的理论依据。本研究分别在盆栽和水培条件下开展试验,盆栽试验设置pH 3.7和6.5两个梯度,选择‘威廉斯B6’‘巴西’和‘南天黄’3个香蕉品种,对比不同品种香蕉对低pH响应的差异性。试验结果显示,低pH显著抑制香蕉生长和养分吸收。种植在高pH 6.5土壤上的3个香蕉品种的生物量及不同部位(根系、假茎和叶片)养分含量(磷、钾、钙和镁)显著高于种植在低pH 3.7土壤上的香蕉。与高pH相比,生长在pH 3.7的土壤上,生物量平均下降77%,氮、磷、钾、钙、镁等养分吸收量下降73%~604%;而相同pH条件下,不同品种间总体上差异不显著。水培试验设置0、25、50、100μmol/L四个铝浓度,香蕉根尖苏木精染色结果显示,随着铝浓度的增加,香蕉根尖颜色逐渐加深,出现明显铝毒现象。香蕉地上部生物量和养分含量(氮、磷、钙和镁)随着铝浓度的增加呈下降趋势。100μmol/L铝浓度显著降低了香蕉根系的生长速率、地上部生物量、叶缘与叶中心SPAD值及钙和镁的吸收量。本研究表明蕉园土壤低pH和铝毒显著影响了香蕉的生长和养分吸收,不同品种间表现出相同的趋势,研究结果为酸性土壤调控提供重要参考,有助于促进香蕉产业提质增效与绿色发展。

Banana(Musa spp.) is an important fruit in tropical and subtropical regions of the world. It plays a crucial role in the development of tropical economy. China is one of the world’s main banana planting countries, with the second highest total production in the world after India. Low pH and Al toxicity are the main limiting factors in banana production and seriously decrease the banana yield and quality. Therefore, identifying the effects of low pH and Al toxicity stress on banana growth and nutrient uptake can provide theoretical basis for regulating the soil health of acid soils.In this study, pot and hydroponic experiments were conducted. The pot experiments were set under soil pH of 3.7 and 6.5, with the banana varieties of ‘Williams B6’(Musa AAA Cavendish cv. Williams B6), ‘Brazil’(Musa AAA Cavendish cv. Brazil) and ‘Nantianhuang’(Musa AAA Cavendish cv. Nantianhuang), to study the differences in the response of banana varieties to low pH. The results showed that low pH significantly inhibited banana growth and nutrient uptake.The three banana varieties grown at high pH 6.5 soils had significantly higher biomass and nutrient contents(N, P, K, Ca and Mg) of different parts(roots, pseudostems and leaves) than those on low pH 3.7 soils. Compared to high pH soils,bananas grown at pH 3.7 showed an average decrease of 77% in biomass and 73%-604% in nutrient uptake of N, P, K,Ca and Mg, while no significant differences were observed among banana varieties. In the hydroponic experiments, four Al concentrations of 0, 25, 50, 100 μmol/L were applied to explore the response to Al stress. The results of hematoxylin staining of banana root tips showed that the colors of banana root tips gradually deepened with the increase of Al concentrations, and the Al toxicity appeared obviously. The above-ground biomass and nutrient contents(N, P, Ca and Mg)of banana showed a decreasing trend with increasing Al concentrations. Banana grown in Al concentrations of 100 μmol/L showed a significant decrease of root growth rates, shoot biomass, SPAD values of leaf margin and leaf center, and Ca and Mg uptake. This study showed that low soil pH and Al toxicity significantly inhibited the growth and nutrient uptake of banana, with the same trend shown among different varieties. This research provides an important reference for acid soil management in banana orchards, and will contribute to the banana quality, nutrient efficiency and green development of banana industry in China.