马尾松种源磷效率研究

选用5个对磷肥反应差异显著的马尾松种源,设计3种磷素水平的盆栽试验以研究马尾松磷效率的种源差异,确立种源磷效率的特异性指标。结果表明:马尾松磷效率的种源差异很大,尤以地处武夷山脉南端的福建武平种源最高,其磷效率高于70%,为最低磷效率种源的2倍左右,该种源在低磷胁迫下具有最大的磷素吸收和利用效率及最高的干物质积累量。在参试的3个南方种源中,广东信宜种源也具有相对较高的磷效率。低磷水平下马尾松种源磷效率与磷素利用效率有关,而与磷素吸收效率相关性较小,磷效率和磷素利用效率高的种源其干物质积累量较高。相关分析表明,低磷胁迫下马尾松种源磷效率与其根体积、侧根数、侧根总长和须根总数等呈显著正相关。结合已有水培和土培试验结果,初步认为侧根总长、侧根数、根体积等根系参数以及根系有机酸分泌物含量、酸性磷酸酶活性等可作为低磷胁迫下马尾松种源磷效率的特异性指标。

Study on Phosphorus Efficiency of Different Provenances of Pinus massoniana

Soil culture experiment at 3 phosphorus levels was conducted to illustrate differences of phosphorus efficiency (PE) between five Pinus massoniana provenances which showed different responses to phosphate fertilizer, and to screen special characteristics indicating PE. The results showed that there existed great differences in PE for provenances tested, among which Wuping of Fujian (distributed over the southern end of Wuyi mountains) was regarded as tolerance provenance to low phosphorus stress with the greatest PE, P absorption and use efficiency, and highest dry matter accumulation under low phosphorus level. PE of Wuping of Fujian was above 70% and about one times higher than those provenances with lowest PE. Among three southern provenances tested, Xinyi of Guangdong was also found to have greater PE. PE was significantly and positively related to P use efficiency, not related to P absorption. The provenances with higher PE had greater dry matter accumulation. PE has a high and positive correlation to root parameters such as root volume, number and total length of lateral roots, and number of fibrous roots under low phosphorus stress. Based on the results of soil and liquid culture experiments, the root parameters above, organic acid amount excreted from roots, and APase activity etc. can be screened as the special characteristics for PE of P. massoniana provenances under low phosphorus stress.