退化喀斯特森林群落常见植物叶片SPAD值变异特征

摘要

Chlorophyll content in plants, as an important parameter of investigation on physiological, biochemical statements, can be sensitively tested to reflect the relationship between plants and environment where they grown. Mostly, the SPAD (Soil and Plant Analyzer Development) value is an indicator reflecting the relative content of plant chlorophyll instead of chlorophyll content to assess the environment and plant growth status. The leaves of several common species, Rosa cymosa, Pyracantha fortuneana, Zanthoxylum armatum and Rhamnus parvifolia,from different succession communities in ChenQi basin(Guizhou),were collected to explore the variation of SPAD values and their reaction to environmental changes of degraded Karst forest. The results showed that: (1) The SPAD values of leaves range from 13.54 to 24.34, with an average value of 18.43. The SPAD values are stable in the same communities but significantly different among plant communities at different succession stages (P<0.05), thin shrub-grassland (16.33), vine-shrub (19.65), shrub (20.90), forest-shrub (18.18) and forest (17.07). This indicates that SPAD value is a response to the plant's habitat conditions. (2) The index, were relatively stable within intraspecies but significantly different among interspecies (P<0.05), this shows that species is a related to SPAD value's change. (3) Observably, the community and species were interaction with SPAD value in the study, with relatively stable within same community but significant differences among different communities (P<0.05), it states that the variation of SPAD values is affected by factors (e.g. environment) other than species. And (4) a remarkably positive correlation (P<0.01) among SPAD values and nitrogen content, leaf temperature, air temperature and dew-point temperature of species collected spot, which indicated that the variability of SPAD value is an comprehensive result under the diverse systematical structure and function degradation of degraded karst forest ecosystems.%叶绿素含量是植物生理生化及生态调查中的一个重要测量参数,植物叶绿素含量能灵敏地反映植物生理状态及其与环境的关系.SPAD(Soil and Plant Analyzer Development)值是反映植物叶绿素相对含量的指标,一定条件下可用SPAD 值代替叶绿素含量进行植物生长环境和健康水平的评估.为探讨退化喀斯特森林不同演替群落植物叶片SPAD值变异特征及其对环境变化的响应,以陈旗小流域内退化喀斯特森林群落中的常见植物为研究对象,分别对其叶片SPAD值进行了测定分析.结果表明,(1)研究区植物叶片SPAD值在13.54~24.34之间变化,平均值为18.43.植物叶片SPAD值在稀灌草丛(16.33)、藤刺灌丛(19.65)、灌木林(20.90)、乔灌过渡林(18.18)和乔木林(17.07)等不同演替阶段植物群落之间差异显著(P<0.05),而在各群落内部均较稳定,表明植物叶片S PA D值的改变一定程度上是对植物生境条件的响应.(2)研究区小果蔷薇(Rosa cymosa)、火棘(Pyracantha fortuneana)、竹叶花椒(Zanthoxylum armatum)和小叶鼠李(Rhamnus parvifolia)4种植物叶片SPAD值在物种内均较稳定,但种间差异显著(P<0.05),说明树种是影响植物叶片SPAD值的重要因子.(3)研究区群落类型、物种均对植物叶片 SPAD 值有显著影响并产生交互作用,但植物叶片 SPAD 值在各群落内部均较稳定,而在不同群落之间有显著差异(P<0.05),表明研究区内植物叶片SPAD值的变异受环境变化等物种以外因素的影响更大.(4)研究区植物叶片SPAD值与叶片氮含量、叶面温度及生长环境的空气温度、露点温度之间均具有极显著正相关关系(P<0.01),表明其变异特征是退化喀斯特森林生态系统结构和功能退化的综合体现.