黄帚橐吾基株克隆生长对不同光照的响应

为了解青藏高原高寒草甸克隆植物黄帚橐吾(Ligularia virgaurea)的生活史对策,通过田间盆栽控制试验,模拟青藏高原东部高寒草甸上由于过度放牧产生的裸地和低、矮的退化草甸的光强,研究黄帚槖吾基株的相对克隆生长速度和克隆性状对不同光照的响应,以期填补有关黄帚槖吾克隆生长领域研究的不足,并为该类毒杂草的防治提供理论依据。结果表明,在自然光照条件下,黄帚橐吾根状茎长度与时间无线性关系;在遮阴环境下,黄帚橐吾根状茎长度与时间之间存在显著的线性关系(P0.05),根状茎长度随着时间延长而显著增长。光照不仅可以直接影响单位长度根状茎生物量,还可以通过影响基株大小从而间接影响单位长度根状茎生物量。黄帚橐吾根状茎的长度与单位长度根状茎生物量之间不存在权衡。光照对黄帚橐吾克隆生长相对速率有显著影响(P0.05),遮阴条件下黄帚橐吾克隆相对生长速率显著大于自然光照条件下的生长速率。因此,在遮阴下根状茎主要功能是觅食,自然光照下根状茎主要功能用于贮藏养料、固定作用。

Response on the clonal growth of Ligularia virgaurea genets to light intensity

Understanding the life history strategies of Ligularia virgaurea in the alpine meadow of the Qinghai-Tibet plateau is important to preventing and controlling this weed.We studied the response to light intensity of clonal growth and traits of L.virgaurea genets in field pots experiments to fill the gap in research and provide a theoretical basis for the prevention and control of this weed.Two light intensity levels were used to simulate the light intensities in bare soil and in low,open vegetation of disturbed meadows on the eastern Qinghai-Tibet plateau.The results showed that there was not a linear relationship between the length of rhizomes in L.virgaurea and the time under full natural irradiance.In shaded conditions,there was a significant positive linear relationship between the length of rhizomes in L.virgaurea and time (P＜0.05).Light intensity directly affected the dry mass per unit rhizome length.It also indirectly affected the dry mass per unit rhizome length by increasing the dry mass of the genets.There was no trade-off between the length of rhizomes and the dry mass per unit rhizome length in L.virgaurea.Light intensity had a significant impact on relative clonal growth rates of L.virgaurea (P＜0.05).The relative clonal growth rates under shaded conditions were significantly higher than those under full natural irradiance.Therefore,the main function of rhizomes is foraging in shaded conditions,but,under the full natural irradiance,their primary role is storage and anchoring.