湿地松不同叶龄针叶氮磷含量及其内吸收率季节规律研究

对福建漳州市长泰县岩溪湖珠集体林场湿地松氮磷含量、N:P比、养分内吸收率的季节动态进行研究。研究得出:湿地松针叶中的N、P含量随针叶的成熟和衰老而依次降低。其中,一年生、二年生和多年生针叶N含量存在显著的季节变化,均表现为夏冬季节显著高于春秋季节(P0.01)。与N的季节动态不同,二年生针叶的P含量的季节变化并不明显,一年生针叶和二年生中的P含量则是夏秋季节高于冬春季节。而多年生中P含量春秋季节显著高于夏冬季节。随着湿地松针叶的成熟和衰老,针叶中的N:P比依次增大。其中,二年生针叶中的N:P比在各个季节均高于16,表明湿地松的生长受到不同程度的P限制。N、P内吸收率分别在65.59%～85.29%和84.13%～93.99%之间波动,本研究中湿地松N内吸收率显著高于前人研究树种的平均值,表明湿地松生长的立地条件极为贫瘠。而湿地松通过提高限制其生长的营养元素的内吸收率来适应贫瘠的立地条件。

Seasonal Dynamics of Nitrogen, Phosphorus Contents and Internal Absorption Factor of Pinus elliottii Leaves in Different Ages

Seasonal dynamics of nitrogen and phosphorus contents, N：P ratio and nutrient resorption of Pinus elliottii leaves was studied at Yanxi Huzhu Forestry Center of Zhangzhou, Fujian. The results showed that N and P concentrations decreased with maturity and senescence. N loading indexes change with season in annual growth, biennial and perennial needle, all expressing for higher in spring than in winter（P 〈 0.01）. N concentrations of different ages leaves in summer and winter were significant higher than those in spring and autumn. P contents of one and two years old leaves in winter and spring were lower than those in summer and autumn. N：P were increased during leaves maturity and senescence, and all more than 16, Pinus elliottii grow will be restricted inordinately.Nitrogen resorption efficiency （NRE） and phosphorus resorption efficiency （PRE） were from 65.59% to 85.29% and from 84.13% to 93.99% through the season, respectively, and PRE was significantly higher than NRE. Pinus elliottii growth barren site conditions jolly, it improves internal absorption factor of nutritive element what limits its growth to adapts to barren site conditions.