磷铝耦合处理对越南油茶幼苗生长及磷铝含量的影响

目的]探究施用磷和铝对越南油茶幼苗生长、磷铝积累及其土壤有效磷铝含量的影响,为揭示油茶适应南方高铝低磷砖红壤环境机理提供参考依据.方法]利用砖红壤种植越南油茶,分别在砖红壤中添加0、0.5、1.0 mmol/kg磷(P0、P1和P2)和0、10.0、20.0 mmol/kg铝(Al0、Al1和Al2),测定分析各磷铝耦合处理下越南油茶幼苗的生长指标、磷铝含量及土壤交换铝和有效磷含量.结果]在砖红壤中添加铝会抑制越南油茶幼苗生长,而添加磷能缓解铝的抑制作用,其中以Al0P2处理幼苗生长效果最佳;添加磷和铝对越南油茶幼苗的地径、苗高、鲜重、根冠比和叶绿素相对含量(SPAD)均有显著影响(P<0.05,下同),但磷和铝对幼苗生长的影响相对独立;添加磷能有效降低越南油茶幼苗根系的铝含量,其中Al0P2处理根系的铝含量较Al0P0处理低35.22%;磷和铝及其交互作用对越南油茶幼苗磷和铝含量的影响显著;添加铝会使土壤交换铝含量提高,而添加磷可降低土壤交换铝含量,以添加1.0 mmol/kg磷降低土壤交换铝含量的效果最明显;磷和铝及其交互作用对越南油茶幼苗根际土壤交换铝和有效磷含量的影响极显著(P<0.01).相关性分析结果表明,土壤有效磷和交换铝含量与越南油茶生长状况和磷铝含量呈显著正相关.结论]在种植越南油茶的砖红壤中添加铝会导致土壤活性铝含量增加,有效磷含量降低,幼苗生长受到抑制,而添加磷能降低土壤活性铝含量,有效改善铝胁迫对越南油茶幼苗根系的毒害,促进幼苗叶绿素合成、生物量累积和对磷的吸收,有利于幼苗生长.

Effects of phosphorus and aluminum interaction on seedling growth of Camellia vietnamensis Huang.and phosphorus and aluminum contents in it

Objective]Effects of phosphorus(P)and aluminum(Al)on seedling growth,P accumulation,Al accumu-lation,available P content and available Al content of Camellia vietnamensis Huang.seedlings were investigated to pro-vide reference for exploration on the adaptation of C.oleifera in the environment with high Al and low P in southern Chi-na.Method]C.vietnamensis seedlings were planted in latosol.Random block experiment was conducted adding 0,0.5, 1.0 mmol/kg P(P0,P1and P2)and 0,10,20 mmol/kg Al(Al0,Al1and Al2)in latosol.Growth indexes,P and Al contents, soil exchangable Al and soil available P and AI content in different treatments were determined and analyzed.Result]Adding Al into latosol restrained C.vietnamensis seedling growth;adding P could alleviate the inhibitory effects of Al, and seedling growth in Al0P2treatment was the best.Adding P and Al had significant effects on ground diameter,seedling height,fresh weight,root/shoot ratio and relative content of chlorophyll(SPAD)of C.vietnamensis(P<0.05,the same be-low),but the effects of P and Al on C.vietnamensis seedling growth were relatively independent.Adding P could effective-ly reduce Al content in root of C.vietnamensis seedlings,and root Al content in Al0P2treatment was 35.22% lower than that in Al0P0treatment.The effects of P,Al and their interaction on P and Al contents on C.vietnamensis seedlings were signifi-cant.Adding Al could increase soil exchangeable Al content,and adding P could reduce soil exchangeable Al content,ad-ding 1.0 mmol/kg P was the most effective in reducing soil exchangeable Al content. P,Al and their interaction had ex-tremely significant influence on exchangeable Al and available P content in rhizosphere soil of C.vietnamensis(P<0.01). The results of correlation analysis showed that soil available P and exchangeable Al content were significantly positively correlated with the growth of C.vietnamensis and contents of P and Al.Conclusion]Adding Al into latosol where grows C.vietnamensis can increase soil active Al content and decrease available P content,which inhibits the growth of seed-lings.Adding P can reduce soil active Al content,which effectively alleviates the harmful effects of Al stress on root of C. vietnamensis seedlings,promotes chlorophyll synthesis,biomass accumulation and P uptake of the seedlings.So adding P is beneficial for the growth of C.vietnamensis seedlings.