低P胁迫对马尾松不同种源根系形态和干物质分配的影响

利用不同地区5个典型马尾松种源，布置3种P水平的盆栽实验，研究马尾松应对低P胁迫时根系形态和干物质分配特征的种源差异。结果表明，P素胁迫的加重导致马尾松干物质积累量的下降和一些根系参数的减小，但植株地下部分的干物质分配量和根系形态参数的相对值却显著增加。低P胁迫下，种源间干物质积累量(包括植株各部分和总的积累量)和侧根数等根系参数差异显著。低P下干物质生产能力较强的福建武平种源对磷肥的敏感性较低，广东信宜和浙江淳安种源次之，类似于大田和水培实验结果。遗传相关分析揭示：侧根发达、须根数量多的种源干物质生产能力强。根体积、侧根数、侧根总长、须根总数等可作为筛选马尾松耐低P种源的有效指标。

Root Morphology and Dry Matter Allocation of Masson Pine:Response of Different Provenances to Low-Phosphorus Stress

Pot experiments in 3 phosphorus levels were conducted with 5 masson pine (Pinus massoniana) provenances in various areas to study the differences of root morphology and dry matter allocation of these provenances under low-phosphorus stress. The results showed that the aggravation of phosphorus deficiency would lead to the decline of the dry matter accumulation and main root parameters, while the allocation of dry matter to roots and the relative value of root parameters would obviously increase. Under low phosphorus stress, there existed significant differences between provenances tested for the dry matter accumulation and root parameters such as number of lateral roots. It was found that the provenance from Wuping of Fujian with the highest productivity under low phosphorus was an excellent provenance with the least sensitivity to phosphorus supply,followed by that from Xinyi of Guangdong and Chun'an of Zhejiang.This result was similar to that from field trials and liquid culture experiment. Genetic correlation analysis demonstrated that the provenances with extensive lateral root systems and more fibrous roots had greater dry matter accumulation. Some root parameters such as root volume, number and total length of lateral roots, and number of fibrous roots could be regarded as the efficient indexes for screening excellent provenances with high phosphorus efficiency in low phosphorus stress.