春季增温对亚热带木本植物物候和生长的影响

Effects of spring warming on phenology and growth of subtropical woody species

气候变暖导致温带地区物种的春季物候期提前。在亚热带和热带地区只有少量的物候事件记录和研究,其气候驱动因素不清楚,阻碍了未来气候变化对这些独特生态区植物物候影响的准确预测。为了确定亚热带地区植物春季物候对温度变化的响应,设计了气候箱控制试验和野外自然试验,研究2个春季增温处理(T1:白天20℃/晚上15℃;T2:白天25℃/晚上20℃,昼夜长均为12 h)对10种亚热带木本植物(4个落叶树种和6个常绿树种)幼苗出芽、展叶时间和幼苗生长高度的影响。结果表明:春季变暖主要对落叶树种出芽和展叶有显著的提前作用,出芽时间变化范围是-0.006~-1.8 d·℃^(-1),展叶时间变化范围是-0.7~-1.6 d·℃^(-1);春季增温显著促进了3个落叶树种幼苗生长;相比于亚热带常绿树种,温度变化对落叶树种春季物候和生长的影响更为重要,这些结果对未来气候变化情景下热带和亚热带植物种群的保护和管理具有重要意义。

Climate warming advances the spring phenology of species in temperate regions.Thereare only a few phenological events recorded and studied in subtropical and tropical regions,andthe driving factors of climate are still unclear,which seriously hinders the accurate prediction ofthe impacts of climate change on plant phenology in these unique ecoregions in the future.Todetermine the differences of the response of plant phenology to temperature changes in subtropicalregion in spring,we designed a climate chamber experiment and a field experiment to test theeffects of two spring warming treatments(T1:20℃during the day and 15℃at night,T2:25℃during the day and 20℃at night.The length of day and night is 12 hours)on the timing ofbudburst and leaf-out and seedling height growth of 10 subtropical woody species(four deciduousspecies and six evergreen species).The results showed that spring warming significantly advancedthe budburst and leaf out of deciduous trees.The timing of budburst ranged from-0.006 to^(-1).8d·℃^(-1),while the timing of leaf-out ranged from-0.7 to^(-1).6 d·℃^(-1).The seedling growth ofthree deciduous trees was markedly promoted by spring warming.Compared with evergreen spe-cies,the effects of temperature change on spring phenology and growth are more important todeciduous tree species.These results are of great significance for the conservation and manage-ment of tropical and subtropical plant populations under climate change.