Mineral nutrients influence photosynthesis and tissue formation; a shift from nitrogen (N)-limited to phosphorus (P)-limited growth induced by high N deposition may change plant growth in terms of physiology and morphology. This experiment showed that absolute and relative N and P supply affected net photosynthesis (source activity) and biomass formation (sink activity), and the relationship between source and sink activities of Holcus lanatus L. under various nutrient treatments. H. lanatus was grown at three N:P ratios (5, 15, 45) with two absolute supply levels of N and P. Between N:P 5 at low level and N:P 45 at high level, and between N:P 45 at low level and N:P 5 at high level, there was a nine-fold difference in N and P supply. Maximum light-saturated net photosynthesis rate (A_max), specific leaf area (SLA), leaf area, and shoot and root biomass were determined during and after the growth process. A_max was minimal at N:P 5 and increased only with increasing absolute N supply. Neither SLA nor leaf area were affected by N:P; increasing absolute P supply significantly increased leaf area. Shoot and root biomass were minimal at N:P 45 and increased dramatically with increasing absolute P supply. Plant biomass was not correlated with A_max. Our results highlight that H. lanatus growth is predominantly controlled by P supply and to a lesser extent by N, whereas net photosynthesis exerted no apparent control on growth under these sink-limited growth conditions. Our findings contribute to understanding of plant growth under sink-limited conditions.

矿物质养分影响光合作用和组织形成；由高氮沉积引起的从有限氮（N）向有限磷​​（P）的转变可能会改变植物的生理和形态。该实验表明，在不同的养分处理条件下，绝对和相对的氮和磷供应影响净光合作用（源活性）和生物量形成（下沉活性），以及Holcus lanatus L.的源下沉活性之间的关系。羊肚菌以三种N：P比率（5、15、45）生长，具有两个绝对的N和P供应水平。在低水平的N：P 5和高水平的N：P 45之间以及在N：P之间在低水平时为45，高水平时为N：P 5，氮和磷的供给相差9倍。最大光饱和净光合作用速率（A_最大值），比叶面积（SLA），叶面积，和枝条和根生物量期间和生长过程后进行了测定。甲_最大值是最小的，在N：P 5和只随绝对氮供应增加。SLA和叶面积均不受N：P影响；增加绝对磷供应量会显着增加叶片面积。在N：P 45时，枝条和根的生物量极少，并且随着绝对磷供应的增加而急剧增加。植物生物量与A _max不相关。我们的结果突出表明H. lanatus生长主要受磷供应的控制，在较小程度上受氮的控制，而净光合作用在这些受水库限制的生长条件下对生长没有明显的控制作用。我们的发现有助于理解水槽有限条件下的植物生长。