马褂木种源磷效率特性差异研究

设计了低磷(5 mg·kg-1)和高磷(180 mg·kg-1)两个磷素处理水平的盆栽实验,研究马褂木6个代表性种源的磷效率特性差异及其相关性状的关系.结果表明,马褂木种源磷效率差异较大,其值变化在15.4%～38.9%.结合考虑种源对磷肥的敏感性及在不同磷素水平下的生长表现,认为湖南通道为耐低磷型或高磷效率的优良种源,而贵州黎平和湖南邵阳则分别为磷素中等敏感型和磷素敏感型优良种源.研究发现,马褂木种源磷效率与磷素的吸收效率有关,而与磷素的利用效率相关性较小.低磷水平下种源的干物质生产能力可很好地指示磷效率的大小.高磷效率的种源在磷胁迫条件下具有干物质积累量高、叶片宽大、数量多、须侧根发达等特点,而低磷效率种源的干物质积累量低、叶片窄小、须侧根不发达,并呈现缺磷症状.

Characteristics of Phosphorus Efficiency of Different Provenaces in Liriodendron chinese

Soil culture experiments at two phosphorus levels (5 mg·kg^-1 and 180 mg·kg^-1) were conducted to study the characteristics of phosphorus efficiency of different provenances of Liriodendron chinese. The result showed that phosphorus efficiency varied from 15.4% to 38.9% with the provenances tested.Based on the sensitivity to phosphorus supply and growth performance at two phosphorus levels,the provenance from Tongdao of Hunan could be considered as a superior provenance with high phosphorus efficiency or high tolerability to phosphorus stress,while that from Liping of Guizhou and Shaoyang of Hunan were two excellent provenances with moderate and strong sensitivity to phosphorus supply respectively.It was found that PE was significantly and positively related to P absorption,but P use efficiency.The dry matter accumulation of provenance under low phosphorus stress was a good indicator of its phosphorus efficiency.Compared with the provenances with low PE,the provenances with high PE possessed greater dry matter accumulation,more and larger leaves,extensive lateral root system and more fibrous roots in phosphorus stress.Provenances with low phosphorus efficiency were observed to appeared symptoms of phosphorus deficiency.