植物生态学报
植物生態學報
식물생태학보
ACTA PHYTOECOLOGICA SINICA
2010年
3期
253-262
,共10页
张晓娜%哈达朝鲁%潘庆民
張曉娜%哈達朝魯%潘慶民
장효나%합체조로%반경민
密度调节%内蒙古典型草原%繁殖对策%资源分配
密度調節%內矇古典型草原%繁殖對策%資源分配
밀도조절%내몽고전형초원%번식대책%자원분배
density regulation%Inner Mongolia typical steppe%reproductive strategy%resource allocation
刈割是内蒙古草原的主要利用方式之一.当植物面对刈割干扰时,可以通过繁殖策略的调节适应变化的环境.研究刈割干扰下植物繁殖策略的调节对于揭示植物的适应与进化机制具有重要意义.为此,选择内蒙古典型草原的大针茅(Stipagrandis)和糙隐子草(Cleistogenes squarrosa),在1979年围封的羊草(Leymus chinensis)样地(对照)和毗邻的长期刈割区对其繁殖策略进行了研究.结果显示:1)长期刈割干扰下,大针茅的种群生物量与对照区无显著差异,由于其株丛生物量显著降低,大针茅种群生物量的维持得益于种群密度的显著增加.糙隐子草的种群生物量比对照区显著提高,由于其株丛生物量与对照区无显著差异,糙隐子草种群生物量的增加也是因为密度的显著提高.因此,密度调节是两种植物应对长期刈割干扰的重要的调节机制.2)长期刈割干扰下,两种植物在无性繁殖和有性繁殖过程所采取的密度调节策略并不相同.大针茅种群生殖株丛的密度无显著变化,非生殖株丛的密度显著提高,导致其非生殖株丛的相对密度显著增加,而生殖株丛的相对密度显著降低.因此刈割干扰下大针茅种群在密度调节上采取了保持有性繁殖株丛密度,增加无性繁殖株从密度的策略.糙隐子草种群非生殖株从的密度显著增加,但生殖株丛的密度增加幅度更大,导致其非生殖株丛的相对密度显著降低,而生殖株丛的相对密度显著提高.因此刈割干扰下糙隐子草种群在密度调节上采取了增加无性繁殖株丛密度的同时,更大幅度地增加有性繁殖株丛密度的策略.3)长期刈割干扰下,两种植物对生物量生殖分配的调节采取了不同的策略.大针茅株丛生物量向生殖枝分配的比例无显著变化,通过降低生殖枝向穗的生物量分配比例,降低了对有性生殖过程的生物量分配的投入;而糙隐子草则通过增加株丛生物量向生殖枝分配的比例,维持生殖枝向穗的生物量分配比例,从而增加了对有性繁殖过程生物量分配的投入.4)长期刈割干扰下,大针茅的株丛面积和株丛分蘖数与对照区无显著差异.糙隐子草株丛面积降低,但是株丛分蘖数无显著变化.本实验说明,植物种群有性繁殖和无性繁殖之间的密度调节和资源分配调节是草原植物应对刈割干扰下的重要调节机制,不同的响应策略影响着植物种群的消长动态.
刈割是內矇古草原的主要利用方式之一.噹植物麵對刈割榦擾時,可以通過繁殖策略的調節適應變化的環境.研究刈割榦擾下植物繁殖策略的調節對于揭示植物的適應與進化機製具有重要意義.為此,選擇內矇古典型草原的大針茅(Stipagrandis)和糙隱子草(Cleistogenes squarrosa),在1979年圍封的羊草(Leymus chinensis)樣地(對照)和毗鄰的長期刈割區對其繁殖策略進行瞭研究.結果顯示:1)長期刈割榦擾下,大針茅的種群生物量與對照區無顯著差異,由于其株叢生物量顯著降低,大針茅種群生物量的維持得益于種群密度的顯著增加.糙隱子草的種群生物量比對照區顯著提高,由于其株叢生物量與對照區無顯著差異,糙隱子草種群生物量的增加也是因為密度的顯著提高.因此,密度調節是兩種植物應對長期刈割榦擾的重要的調節機製.2)長期刈割榦擾下,兩種植物在無性繁殖和有性繁殖過程所採取的密度調節策略併不相同.大針茅種群生殖株叢的密度無顯著變化,非生殖株叢的密度顯著提高,導緻其非生殖株叢的相對密度顯著增加,而生殖株叢的相對密度顯著降低.因此刈割榦擾下大針茅種群在密度調節上採取瞭保持有性繁殖株叢密度,增加無性繁殖株從密度的策略.糙隱子草種群非生殖株從的密度顯著增加,但生殖株叢的密度增加幅度更大,導緻其非生殖株叢的相對密度顯著降低,而生殖株叢的相對密度顯著提高.因此刈割榦擾下糙隱子草種群在密度調節上採取瞭增加無性繁殖株叢密度的同時,更大幅度地增加有性繁殖株叢密度的策略.3)長期刈割榦擾下,兩種植物對生物量生殖分配的調節採取瞭不同的策略.大針茅株叢生物量嚮生殖枝分配的比例無顯著變化,通過降低生殖枝嚮穗的生物量分配比例,降低瞭對有性生殖過程的生物量分配的投入;而糙隱子草則通過增加株叢生物量嚮生殖枝分配的比例,維持生殖枝嚮穗的生物量分配比例,從而增加瞭對有性繁殖過程生物量分配的投入.4)長期刈割榦擾下,大針茅的株叢麵積和株叢分蘗數與對照區無顯著差異.糙隱子草株叢麵積降低,但是株叢分蘗數無顯著變化.本實驗說明,植物種群有性繁殖和無性繁殖之間的密度調節和資源分配調節是草原植物應對刈割榦擾下的重要調節機製,不同的響應策略影響著植物種群的消長動態.
예할시내몽고초원적주요이용방식지일.당식물면대예할간우시,가이통과번식책략적조절괄응변화적배경.연구예할간우하식물번식책략적조절대우게시식물적괄응여진화궤제구유중요의의.위차,선택내몽고전형초원적대침모(Stipagrandis)화조은자초(Cleistogenes squarrosa),재1979년위봉적양초(Leymus chinensis)양지(대조)화비린적장기예할구대기번식책략진행료연구.결과현시:1)장기예할간우하,대침모적충군생물량여대조구무현저차이,유우기주총생물량현저강저,대침모충군생물량적유지득익우충군밀도적현저증가.조은자초적충군생물량비대조구현저제고,유우기주총생물량여대조구무현저차이,조은자초충군생물량적증가야시인위밀도적현저제고.인차,밀도조절시량충식물응대장기예할간우적중요적조절궤제.2)장기예할간우하,량충식물재무성번식화유성번식과정소채취적밀도조절책략병불상동.대침모충군생식주총적밀도무현저변화,비생식주총적밀도현저제고,도치기비생식주총적상대밀도현저증가,이생식주총적상대밀도현저강저.인차예할간우하대침모충군재밀도조절상채취료보지유성번식주총밀도,증가무성번식주종밀도적책략.조은자초충군비생식주종적밀도현저증가,단생식주총적밀도증가폭도경대,도치기비생식주총적상대밀도현저강저,이생식주총적상대밀도현저제고.인차예할간우하조은자초충군재밀도조절상채취료증가무성번식주총밀도적동시,경대폭도지증가유성번식주총밀도적책략.3)장기예할간우하,량충식물대생물량생식분배적조절채취료불동적책략.대침모주총생물량향생식지분배적비례무현저변화,통과강저생식지향수적생물량분배비례,강저료대유성생식과정적생물량분배적투입;이조은자초칙통과증가주총생물량향생식지분배적비례,유지생식지향수적생물량분배비례,종이증가료대유성번식과정생물량분배적투입.4)장기예할간우하,대침모적주총면적화주총분얼수여대조구무현저차이.조은자초주총면적강저,단시주총분얼수무현저변화.본실험설명,식물충군유성번식화무성번식지간적밀도조절화자원분배조절시초원식물응대예할간우하적중요조절궤제,불동적향응책략영향착식물충군적소장동태.
Aims Stipa grandis and Cleistogenes squarrosa are two important bunchgrass species in Inner Mongolia typical steppe. Stipa grandis is a dominant species in undisturbed communities, while C. squarrosa becomes the domi-nant species in degraded communities. It is important to understand the regulation mechanisms of the two popula-tions under mowing disturbance, especially those regulating sexual and asexual reproduction. We addressed four questions: 1) Do the two populations exhibit density-dependent regulation under mowing disturbance? 2) If so, how do they regulate sexual and asexual reproduction? 3) Do the species modify their biomass allocation patterns under mowing disturbance, and, if so, how do they change their allocation patterns? 4) Does mowing disturbance affect plant basal area and tiller number?Methods This study was conducted in a long-term fenced site and a long-term mowed site at the Inner Mongolia Grassland Ecosystem Research Station of Chinese Academy of Sciences in 2007. We examined the density regu-lation and resource allocation regulation of S. grandis and C. squarrosa under different management regimes. Important findings Under mowing disturbance, S. grandis exhibited no significant change in population bio-mass, while C. squarrosa significantly increased. Because mean plant biomass of S. grandis decreased signifi-cantly and that of C. squarrosa did not change, density increase plays an important role for the two species in population biomass production. The two species exhibited different strategies in density-dependent regulation of asexual and sexual reproductive processes. For S. grandis, density increased in non-reproductive plants, but was unchanged in reproductive plants under mowing disturbance, which led to relative density increasing in non-reproductive plants and decreasing in reproductive plants. For C. squarrosa, the densities of both reproduc-tive and non-reproductive plants increased significantlv at the mowed site. The relative density increased in re-productive plants, but decreased in non-reproductive plants. The two species showed opposite reproductive allo-cation manipulation strategies under mowing disturbance. Stipa grandis significantly decreased reproductive bio-mass allocation by decreasing the biomass fraction of spikes in reproductive tillers. In contrast, C. squarrosa sig-nificantly increased reproductive biomass allocation by increasing the fraction of reproductive tiller biomass in plant biomass. No significant changes were found in S. grandis basal area and tiller number under mowing dis-turbance. Likewise, no significant change was found in C. squarrosa tiller number, but its basal area significantly decreased.
