不同磷肥对尾巨桉DH3229苗木生长及抗性生理的影响

Phosphorus fertilizers on the growth and resistance physiology ofEucalyptus urophylla × Eucalyptus grandis DH3229 seedlings

以两个月生盆栽尾巨桉DH3229组培苗为试验对象,以不施肥为对照(CK),研究不同磷肥处理[m钙镁磷∶m磷酸一铵=10∶3(P1)、m钙镁磷∶m磷酸一铵=1∶1(P2)、钙镁磷(P3)、磷酸一铵(P4)]对其生长和抗性生理指标的影响,找出对尾巨桉DH3229苗木生长促进效果较佳的磷来源。结果表明,与CK相比,4种不同磷肥处理对苗木的各生长指标均有显著的促进作用,根冠比显著降低,P4处理对苗木促生效果最优,且P4、P2处理对苗木生长及苗木质量指数的促进效果优于P1、P3处理;4种磷肥处理后,苗木叶片可溶性糖、蛋白含量显著提高,丙二醛(MDA)含量及4种抗氧化酶活性[过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)]显著降低。4种磷肥处理均有利于促进桉树苗木的生长。主成分分析(PCA)表明,P4和P2处理的综合得分最高,分别为2.85和1.52,对苗木生长产生积极的影响,其中肥料中的磷酸一铵对苗木生长的促进作用占主导地位,桉树人工林追肥时以水溶性磷酸一铵作为主要磷源,可适当补充养分释放迟缓、肥效长的钙镁磷肥。

Two-month-old potted Eucalyptus urophylla×Eucalyptus grandis DH3229 tissue-cultured seedlings were used to study the effects of phosphate fertilizer treatments on the growth and resistance physiological indicators.Five groups were tested:no fertilizer control(CK),10∶3 ratio of calcium magnesium phosphate(CMP)to monoammonium phosphate(MAP)(P1),1∶1 ratio of CMP∶MAP(P2),CMP(P3),and MAP(P4).All of the phosphate fertilizers had a significant impact on the seedling growth-promoting indicators and the root-shoot ratio.P4 had the largest overall effect on seedling growth,and P4 and P2 were better at promoting seedling growth and the quality index.The soluble sugar and protein contents of the seedling leaves significantly increased in all of the fertilized groups,but the malondialdehyde(MDA)content and antioxidant enzyme activities[superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),and polyphenol oxidase(PPO)]were reduced.Principal component analysis(PCA)showed that the P4 and P2 treatment groups had the highest comprehensive scores(2.85 and 1.52,respectively),indicating a positive impact on seedling growth.MAP played a dominant role in growth promotion.Therefore,Eucalyptus plantations may use MAP fertilizers as the primary source of phosphorus for topdressing,supplemented with the slow release of nutrients from CMP fertilizer.