广东鹤山人工林群落主要优势植物的热值和灰分含量

Caloric value and ash content of dominant plants in plantation communities in Heshan of Guangdong,China

从广东鹤山南亚热带丘陵5种人工林群落中采集20种主要植物器官及3种群落凋落叶样品,利用PARR-1281氧弹热量计和马福炉分别测定样品的干质量热值和灰分含量,再计算去灰分热值;按器官、个体和生长型等比较分析植物的热值和灰分特征.结果表明:植物各器官的干质量热值、去灰分热值分别在10.7～22.17和13.89～23.04kJ·g-1之间,叶片的干质量热值和去灰分热值明显高于其他器官(P<0.05).个体加权平均干质量热值和去灰分热值分别在14.24～19.43和16.63～20.99kJ·g-1.群落各层次植物去灰分热值平均值的高低依次为:乔木(19.55kJ·g-1)>灌木(19.46kJ·g-1)>草本(18.77kJ·g-1),其中,乔木层树木的去灰分热值平均值大小为:本地针叶树(19.86kJ·g-1)>本地阔叶树(19.55kJ·g-1)>外来桉树(19.18kJ·g-1),灰分含量的排序则相反.马占相思林、针叶林和木荷林群落的凋落叶热值均高于所在林分各层次的热值(P<0.01),马占相思林和针叶林的凋落叶热值大于所在乔木层叶片的热值,而木荷林凋落叶热值小于乔木层叶片的热值.

Different parts of twenty dominant plant species in five plantation communities on the subtropical hilly lands in Heshan of Gunagdong as well as the litters from three of the five plantation communities were sampled, and their gross caloric value （GCV） and ash content were measured by using a PARR-1281 oxygen bomb calorimeter and a muffle furnace. Based on the measurements, the ash-free caloric value （AFCV） of the samples was calculated, and the characteristics of caloric value and ash content of the samples, according to plant part, individual, and plant growth form, were analyzed. The results showed that the GCV and AFCV of leaf, branch, stem wood, stem bark, and root were in the range of 10. 7-22. 17 kJ · g^-1 and 13.89-23.04 kJ · g^-1, respectively. The GCV and AFCV of leaf were significantly higher than those of other parts （P 〈 0. 05 ）, and the individual plant＇ s weighted mean values of GCV and AFCV were in the range of 14. 24-19.43 and 16.63-20. 99 kJ · g^-1, respectively. The mean AFCV of plantation communities was in the order of tree layer （ 19.55 kJ · g^-1 ） 〉 shrub layer （ 19.46 kJ · g^-1 ） 〉 herb layer （ 18.77 kJ · g^-1 ）, with indigenous coniferous tree （19. 86 kJ · g^-1） 〉 indigenous broad-leaved tree （19. 55 kJ · g^-1） 〉 exotic eucalyptus （ 19. 18 kJ · g^-1 ）, while the mean ash content was just the opposite. In Acacia mangium, coniferous, and Schima plantation communities, the GCV and AFCV of litters were higher than those of various plant parts （P 〈 0. 01 ）. The litter-falls in A. mangium and coniferous plantations had higher mean GCV and AFCV than the litters and fresh leaves of tree layer, while the fresh leaves of tree layer in Schima plantation showed higher mean GCV and AFCV.