黑河下游黑果枸杞叶片C、N、P特征及对土壤水盐的响应

研究植物叶片碳(C)、氮(N)、磷(P)计量特征及其与环境因子相关性将为揭示植物对营养元素需求和环境互馈能力提供理论基础。以内蒙古额济纳旗黑河下游距主河道由近及远选择的8个黑果枸杞(Lycium ruthenicum Murr.)优势种群落为研究对象,分析其在不同水分、盐分土壤层环境下叶片C、N、P含量及比值特征,探讨黑果枸杞群落分布的主要限制元素和土壤水盐对其化学计量的影响。研究结果显示:黑果枸杞群落C含量为(331.56±11.99) mg/g,N含量为(13.17±2.92) mg/g,P含量为(2.48±1.64) mg/g,元素C与N、N与P之间呈正相关关系,C与P呈负相关关系,N与C∶N、P与C∶P及N∶P之间呈极显著负相关关系(P0.01);浅层土壤(0—40 cm)水分与P含量呈极显著负相关(P0.01),与C∶P呈显著正相关(P0.05),深层土壤(40—80 cm)水分、盐分均与N含量呈显著负相关(P0.05),与C∶N呈极显著正相关(P0.01)。结果表明:黑果枸杞C∶N主要由N限制,C∶P、N∶P主要由P限制,N∶P小于限制性养分理论阈值14,指示其生长主要受到N限制;黑果枸杞叶片N含量及C∶N比值对深层土壤水分和盐分具有协同响应特征,反映了荒漠植物在干旱盐渍环境中的抗逆境策略。

Characteristics of C, N, P, and their response to soil water and salt in leaves of Lycium ruthenicum in the lower reaches of the Heihe River

Studying the carbon (C), nitrogen (N), and phosphorus (P) characteristics of leaves and their correlation with environmental factors provides a theoretical basis for revealing the plant''s demand for nutrient elements, and the adaptability and feedback to the environment. Perpendicular to the channel of the Heihe River, eight communities dominated by Lycium ruthenicum Murr were selected, from the closest to the farthest, in Ejina Banner, Inner Mongolia. The contents of C, N and P in different water and salt environments were analysed, to explore the main limiting elements of the distribution of communities and the effects of soil water and salinity on their stoichiometry. The results showed that the average C content in the communities was (331.56±11.99) mg/g, the N content was (13.17±2.92) mg/g, and the P content was (2.49±1.64) mg/g. C and N, and N and P were positively correlated, and C and P were negatively correlated; N and C:N, P and C:P, and N:P showed a significant negative correlation. For shallow soil (0-40 cm), there was a significant negative correlation between water and P contents (P < 0.01), and a significant positive correlation with C:P (P < 0.05). There was a significant negative correlation between water and soluble total salt and N content in deep soil (40-80 cm) (P < 0.05), which was significantly positively correlated with the C:N ratio (P < 0.01). Previous studies have shown that:C:N is mainly restricted by N; C:P and N:P are mainly restricted by P; and N:P is smaller than the theoretical limit of 14 for limiting nutrients, indicating that its growth is mainly limited by N. The content of N and C:N have the same response characteristics to deep soil moisture and salinity, reflecting the anti-adversity strategy of desert plants in arid saline environment, which is one of the strategies that the community uses to adapt to drought and saline-alkali stresses.