理解植物各器官间功能性状的关联, 有助于确定控制功能性状的内在机制以及性状间的比例关系。基于内蒙古温带草地19个地点、42种优势草本植物的野外观测, 分析了叶片、茎、生殖器官、细根和粗根间功能性状(N、P含量、N:P、比叶面积、比根长以及叶片和细根的组织密度)的关联。主要结果如下: 在种群和物种水平上, 各器官的N和P含量都显著正相关, 比叶面积与叶片N、P含量和组织密度在种群水平上显著负相关, 而在物种水平上没有显著的相关关系; 而比根长仅在种群水平上与细根的组织密度显著负相关。N、P含量以及N:P在各器官之间一致呈显著正相关, 而比叶面积和比根长没有显著的相关关系。叶片和细根的组织密度在种群水平上显著负相关, 而在物种水平上没有显著的相关关系。非禾草比禾草相应器官(除茎外)的N、P含量高, 但二者茎的N、P含量没有显著的差异; 豆科植物比非豆科植物相应器官的N含量高, 而P含量没有显著的差异。

<em>Aims</em> The temperate grasslands in Inner Mongolia, representing a great diversity in vegetation types (desert steppe, typical steppe and meadow steppe) and function groups (grass/herb, legume/non-legume), are ideal places to test the hypothesized functional trait relationships among plant organs. Our main objective in this study was to test whether plant functional traits vary in a coordinated fashion both within and across organs. <em>Methods</em> Based on the field observation during July and August in both 2006 and 2007, we measured suites of ecophysiological traits of 42 grassland species from 19 sites in Inner Mongolia. The longitude of the study region ranges from 112.82&deg; to 120.12&deg; (E), and the latitude ranges from 41.76&deg; to 49.89&deg; (N). N and P concentrations, N:P ratios of leaves, stems, reproductive structures, fine roots (diameter < 1 mm) and coarse roots (diameter > 1 mm) as well as tissue density of leaf and fine root and specific leaf area/specific root length were determined. <em>Important findings</em> At both population and interspecific level, N and P concentrations were positively correlated within each organ. Specific leaf area was negatively correlated with leaf N and P concentrations and tissue density at the population level but not at the interspecific level. Specific root length was negatively related to fine root tissue density at population level. Plants with low leaf or fine root tissue density had leaves or fine roots with high N concentrations and large specific leaf area or specific root length. N and P concentrations as well as N: P ratios were also consistently correlated across all organs, but no correlation between specific leaf area and specific root length was observed. At the population level there existed a weak negative correlation between leaf and fine root tissue density while at interspecific level this relationship disappeared. Grasses had lower N and P concentrations than herbs in leaves, reproductive structures and roots, but not in stems. Legumes had higher N concentrations than non-legumes in all organs, but they showed no significant differences in P concentrations.

以浙江天童常绿阔叶林、常绿针叶林和落叶阔叶林为对象, 通过对叶片和凋落物C:N:P比率与N、P重吸收的研究, 揭示3种植被类型N、P养分限制和N、P重吸收的内在联系。结果显示: 1)叶片C:N:P在常绿阔叶林为758:18:1, 在常绿针叶林为678:14:1, 在落叶阔叶林为338:11:1; 凋落物C:N:P在常绿阔叶林为777:13:1, 常绿针叶林为691:14:1, 落叶阔叶林为567:14:1; 2)常绿阔叶林和常绿针叶林叶片与凋落物C:N均显著高于落叶阔叶林; 叶片C:P在常绿阔叶林最高, 常绿针叶林中等, 落叶阔叶林最低, 常绿阔叶林和常绿针叶林凋落物C:P显著高于落叶阔叶林; 叶片N:P比也是常绿阔叶林最高、常绿针叶林次之, 落叶阔叶林最低, 但常绿阔叶林凋落物N:P最低; 3)植被叶片N、P含量间(N为x, P为y)的II类线性回归斜率显著大于1 (p < 0.05), 表明叶片P含量的增加可显著提高叶片N含量; 凋落物N、P含量的回归斜率约等于1, 反映了凋落物中单位P含量与单位N含量间的等速损耗关系; 4)常绿阔叶林N重吸收率显著高于常绿针叶林与落叶阔叶林, 落叶阔叶林P重吸收率显著高于常绿阔叶林和常绿针叶林。虽然植被的N:P指示常绿阔叶林受P限制, 落叶阔叶林受N限制, 常绿针叶林受N、P的共同限制, 但是N、P重吸收研究结果表明: 受N素限制的常绿阔叶林具有高的N重吸收率, 受P限制的落叶阔叶林并不具有高的P重吸收率。可见, 较高的N、P养分转移率可能不是植物对N、P养分胁迫的一种重要适应机制, 是物种固有的特征。

为了探究青藏高原东部窄叶鲜卑花(Sibiraea angustata)灌木不同器官碳(C)、氮(N)、磷(P)含量的分配格局及其生态化学计量特征, 该文采用分层随机抽样方法布设样地, 选择16个窄叶鲜卑花灌丛样地, 分别采集窄叶鲜卑花灌木根、茎、叶、当年枝和果等植物器官样品, 并分析样品C、N、P含量及其计量比。结果表明: C、N、P在不同器官中的含量分别表现为茎&#x0003E;当年枝&#x0003E;果&#x0003E;根&#x0003E;叶; 叶&#x0003E;果&#x0003E;当年枝&#x0003E;茎&#x0003E;根; 果&#x0003E;叶&#x0003E;当年枝&#x0003E;根&#x0003E;茎。窄叶鲜卑花各器官中C含量相对稳定, N、P含量变异系数较大, 在根部的变异系数最大。在不同器官中N:P的范围为7.12-12.41, 其值变化不大, N:P变异系数的最小值在当年枝中, 说明N:P在当年枝中的内稳性较高。在该灌木植物体中C与N之间、C与P之间呈极显著的负相关关系, C对N、P具有稀释作用; N与P呈极显著正相关关系, N与P间具有较好的耦合协同性。分析发现: 窄叶鲜卑花不同器官C、N、P化学计量特征在一定程度上符合内稳态理论和生长速率理论, 其元素分配与器官所执行的功能密切相关; 同时指出在物种水平上应当谨慎使用生态化学计量比来判断养分的限制情况。