不同供氮水平下加硅对香蕉生长与氮营养的影响

采用砂培方法,探讨在正常供氮(200mg/L)和高供氮条件下(400mg/L)加硅对3个香蕉品种生长与氮营养的影响。结果表明:正常供氮和高供氮条件下加硅显著影响3个香蕉品种的生物量、根系活力、硝态氮含量、全氮与硅含量,显著影响氮、硅在根系与地上部分的分配比例,不同品种香蕉响应特征不同,香蕉硅氮代谢相互影响。加硅对宝岛蕉和威廉斯蕉地上部分生物量或根系生物量在2个供氮水平间的变化规律影响不显著,加硅降低或提高这种变化程度。巴西蕉在正常供氮条件下、宝岛蕉和威廉斯蕉在高供氮条件下,加硅提高根系活力,分别较对照提高46.0%、38.4%和1.86倍;加硅降低巴西蕉根系氮与叶片氮含量比例,宝岛蕉、威廉斯蕉在正常供氮条件下加硅提高根系中氮/假茎氮含量比例;加硅显著提高香蕉叶片硅含量,较对照提高17.6%～102.3%;加硅对根系和假茎硅含量影响分别与供氮水平与香蕉品种有关;高氮不加硅条件下,根系中硅含量与氮含量呈显著正相关。

Effect of Silicate on Banana Growth and Nitrogen Nutrition with Different Nitrogen Supply Level

The effect of silicate (Si) on the growth and nitrogen (N) nutrition of three banana varieties with normal (200 mg/L) and higher (400 mg/L) nitrogen supply level through sand culture experiments was studied. The biomass of shoots and roots, root activity, concentration of nitrate, total nitrogen and silicon, and the distribution ratio in roots and shoots were changeable by adding silicon. The three banana varieties tested had different responding characteristic. N metabolism had interreaction with Si. Adding silicon increased or reduced markedly the change extent, but among two nitrogen supply levels the change trend had no significant difference. Root activity of ‘Brazil’ banana at normal, ‘Baodao’ and ‘Weiliansi’ banana at higher nitrogen supply level increased distinctly by 46.0%, 38.4% and 186% compared with the control treatment respectively after adding silicon. The ratio of total N concentration in roots to that in leaves of ‘Brazil’ banana reduced markedly after adding silicon, while the ratio of roots to that in pseudo stems of ‘Baodao’ and ‘Weiliansi’ banana at normal nitrogen supply level increased. Silicon concentration in leaves of three banana varieties tested increased by 17.6%-102.3% after adding silicon compared with the control treatment. By adding silicon the change of silicon concentration in roots and that in pseudo stems were related to N supply level and banana varieties respectively. In roots N concentration showed significant linear relationship with silicon concentration at higher nitrogen supply level with no silicon supply.