摘要
密度制约是植物种内竞争效应之一.叶面是植物与外界环境交换物质、能量的有效渠道之一,叶面积指数是植物种群资源利用率和维系植物碳平衡的重要指标.以叶面积指数为测度,测定不同土壤水分条件下叶面积指数与密度间的关系来判定春小麦有效能量利用与密度间的关系,并得知小麦在营养生长期（抽穗期以前）各水分条件下的叶面积指数均随种植的密度递增,而在抽穗期叶面积指数明显下降,在高密度区（4000～10000）尤为明显,且密度1000～10000的叶面积指数趋于稳定.从拔节期到成熟期水分条件正常的叶面积指数比干旱处理的明显要高,而且主要表现在高密度区,但是它们的变化趋势基本一致.结果表明春小麦的穗粒数、千粒重和产量的变化趋势也是和叶面积指数一致的,这充分反映了叶面积指数与植物种群资源利用率或生物量有着密切的关系,同时表明干旱胁迫抑制了植物群落的能量利用.因此,对植物叶面积的研究将对探讨植物物质能量交换的平衡规律具有重要的意义.
The density restriction is one of population competition effects. Leaves are the critical organs for plants to exchange matter and energy with the outside environment. Therefore, the leaf area index （LAI） is an important parameter to describe how plant populations use the resources and maintain a positive carbon balance. Therefore, the present paper takes into account the density, leaf area coefficient and leaf area index of spring wheat as the major variables and measures the relationship between the density and the leaf area index under two different soil water content levels （i. e. the Drought treat and the Control）. The sowing density gradient is designed as 1,10,100, 1000,4000, 10000m^-2 at each soil moisture level. Our experiment results are as follows： （1） the actual density of the populations with the sowing density of 1000m^-2 is consistent from three-leaf stage to ripening stage under both the Drought treatment and the Control, but those with the sowing density 4000 - 10000m^-2 begin to decline rapidly after elongation stage, i.e. accruing self-thinning; （2） the leaf area indexes of spring wheat increase with the increase of sowing density under two soil moisture levels during the nutritional growing period （i.e. before the heading stage） ; （3） but the leaf area indexes begin to drop obviously in the heading stage, especially in the high density regions （4000 - 10000m^-2）, and the leaf area index curves tend to smoothen from sowing density 1000 to 10000 （the LAI is about 8 and 12 under the Drought treat and the Control, respectively） ; （4） from elongation stage to the ripening stage, the leaf area indexes of the Control is notably higher than that of the Drought, especially in the high density region, however, their trends of change are similar; （5） the trends of the number of grains per tiller, 1000-grain-weight and yield for each sowing density accord with the LAI under different moisture conditions. Our results show that the LAI can reflect the situation of t
出处
《生态学报》
CAS
CSCD
北大核心
2006年第7期2281-2287,共7页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(3017016190102015)~~
