摘要
对不同季节浙江北山七子花群落18种优势植物叶的热值和灰分含量进行了研究,探讨了生境片断化所造成的影响。结果表明:(1)不同种类植物叶的灰分含量有较大差异,与植物自身的遗传特性有关(主要是叶的元素含量),其中仅乔木层算盘子(Glochidion puberum)和灌木层华箬竹(Sasamorpha sinica)的灰分含量高于10%,其他植物灰分含量较低;不同季节植物的灰分含量不同,且具有不同的季节变化趋势;从群落林冠到地被层,各层植物叶的平均灰分含量由高到低依次为乔木层(7.49%±2.59%)、灌木层(7.20%±3.22%)、草本层(6.68%±1.02%)和间层(6.28%±1.31%),但层次间差异不显著(p>0.05)。(2)不同种类植物叶的去灰分热值变化范围较大,有6种植物的去灰分热值高于20.00 kJ/g,4种植物低于18.00 kJ/g,同一层次内常绿植物叶的去灰分热值一般比落叶植物高;从林冠到地被层,各层植物叶的去灰分热值由高到低依次为灌木层((20.33±2.29)kJ/g)、乔木层((19.92±1.05)kJ/g)、间层((19.71±3.26)kJ/g)和草本层((18.14±0.74)kJ/g),仅乔木层和草本层之间的差异达到显著水平(p<0.05);不同季节植物叶的去灰分热值变化较为复杂,其中多数植物在春秋季热值含量较高,夏季热值含量较低。(3)对不同生境条件下3种乔木植物叶的热值和灰分含量的比较研究显示,由于受到片断化后光照增强等因素的影响,与林内相比林外生境植株叶的干重热值和去灰分热值均明显升高(p<0.05),而灰分含量变化规律不明显。分析认为,生长速率慢和某些高热值成分的积累是造成片断化条件下植物叶热值升高的主要原因。
Subtropic evergreen and deciduous broadleaved mixed forest forms the transitions from deciduous broadleaved forest to evergreen broadleaved forest. This forest type has an extensive distribution in subtropical mountainous regions of China. This paper focuses on the caloric value, ash content and their dynamics in various layer mature leaves of the dominant plant species in the community. The sampling site was located in the broadleaved forest community at Bei Mountain of Zhejiang Province （29°13′N, 119°38′E）, and the caloric value was measured by GR3500 type oxygen bomb calorimeter.
The ash content of the community species ranged from 4.49% （ Rosa wichuriana） to 12.19% （ Sasamorpha sinica）, and varied with plant species and sampling seasons. Among 18 plant species in our study, only two species＇ ash contents （ S. sinica and Glochidion puberum） exceeded 10%. The rank order of the average ash contents in the leaves was the following： tree layer （7.49 % ± 2.59 % ） 〉 shrub layer（7.20% ±3.22%） 〉 herbaceous layer （6.68%±1.02%） 〉 liana layer （ 6.28% ± 1.31% ）, and the differences among those layers were found not to be significant by nonparametric tests （p 〉 0.05）. Compared with other plants in tropical and subtropical zones, our study plants had relatively high ash contents （7.33%± 2.15%） in leaves, similar only to some mangrove woods in Dongzhai Harbor Mangrove Forest Reserve of Hainan Province. The ash contents were related with amounts of nutrient elements absorbed in the plant body, which could indicate the role of element enrichment of plants. Levels of these element enrichment in plant components depended on their respective need for elements, and were related with element contents in soils.
Ash-free caloric values of community species ranged from 16.28% （Pueraria edulis） to 23.55% （ Camellia fraterne ）, which varied among plant species and sampling seasons. Among the 18 plant species, 6 species had high ash-free caloric values （ 〉 20.
出处
《生态学报》
CAS
CSCD
北大核心
2006年第6期1709-1717,共9页
Acta Ecologica Sinica
基金
浙江省自然科学基金资助项目(1399277)
浙江省生态学重点学科资助项目~~
关键词
灰分含量
热值
季节变化
七子花
ash content
caloric value
seasonal dynamic
Heptacodium miconioides
