摘要
分别在适宜和模拟低温胁迫下，测定了青藏高原3种橐吾属植物幼苗生物量的分配模式、相对生长率（RGR）、可溶性糖含量及膜渗漏率，并计算半致死温度（LT50），旨在了解这3种植物幼苗的生长特性、对低温胁迫的忍受力及其种间差异，探讨3种橐吾幼苗对高寒环境的适应能力。结果表明：3种植物的萌发初期，子叶迅速伸展，而后根／冠比快速增加，相对生长率在萌发后10～15d达到峰值，根／冠比与生物量的累积呈极显著正相关关系；经4℃低温处理后，3种植物幼苗的存活率均超过70％，RGR峰值降低且滞后出现，回归分析表明RGR降低量的64％是由根部生物量的降低引起的；黄帚橐吾、箭叶橐吾及掌叶橐吾的LT50值分别为-8．24、-8．14、-7．28℃，表明3种植物幼苗均能够忍受苗期短暂的低温胁迫而实现种群更新；经-5℃低温处理，三者叶片中的可溶性糖含量分别增加3．61、2．90、1．61倍，而游离脯氨酸分别增加2．57、4．40、37．68倍，表明3种橐吾各自通过不同的代谢调节机制提高自身抗寒能力。总之，3种橐吾属植物均具有良好的适应青藏高原高寒气候环境的生活史对策。
Several growth and physiological indexes, such as bi growth rate （RGR）, soluble sugar content, membrane leakage （LT50）, from the omass allocation pattern, relative rate and semilethal temperature of seedlings of three Ligularia species （ L. virgaurea, L. sagitta, and L. przewalskii ） eastern Qinghai-Tibet Plateau were determined under suitable and simulated low temper- ature conditions, in order to understand the growth traits, endurance to low temperature, inter- specific difference of three seedlings, and their adaptability to alpine environment. The results showed that ： （ 1 ） Cotyledons of three seedlings extended rapidly at the early stage of seed germi- nation, after which root/shoot ratio increased rapidly, RGR reached the peak after 10-15 days of seed germination, and a significant positive correlation between the root/shoot ratio and biomass accumulation was evident. （2） Survival rates of the three seedlings were more than 70% under 4 ℃, but that of L. przewalskii was relatively lower than those of the other two species. RGR peak was significantly delayed and reduced, and 64% reduction of the RGR peak was caused by de- creased root biomass ratio of seedlings. （3） LT50 values of the three seedlings were -8.24, -8.14 and -7.28 %, respectively, indicating that the three species could achieve the regenera- tion of their population via enduring short cold stress at the seedling stage. （4） After low temper- ature （ -5 ℃ ） treatment, the soluble suzar content increased by 3.61. 2.90 and 1.61 folds and the free proline content increased by 2.57, 4.40 and 37.68 folds in leaves irom the three species, respectively, suggesting that the three species can improve their abilities of cold resistance through utilizing different metabolic regulation mechanisms. In conclusion, our results suggest that all the three species of the genus Ligularia have good life history strategies to adapt to the al- pine condition in the Qinghai-Tibet Plateau.
出处
《生态学杂志》
CAS
CSCD
北大核心
2015年第12期3319-3326,共8页
Chinese Journal of Ecology
基金
国家自然科学基金项目(31270429
31470021)资助
关键词
高寒草场
橐吾属
低温胁迫
生活史策略
种群更新
alpine grassland
Ligularia Cass.
low temperature stress
life history strategy
population regeneration.
