作　　者： ; ; ; ; ;

机构地区： 中国科学院华南植物研究所

出　　处： 《生态学报》 2003年第10期1984-1990,共7页

摘　　要： 应用热脉冲式树液流测定系统和自动气象站 1 999年 9月～ 2 0 0 0年 9月的观测资料 ,探讨了广东省湛江市雷州半岛两个桉树人工林树液流通量 (Sap flux density,SFD)的时空动态及其与环境因子的相关关系。河头和纪家两地桉树林的树液流变化具有明显的昼夜节律性 ,大约从清晨 7:0 0开始萌动 ,1 2 :0 0以后达到峰值 ,夏季连续 4 d中 (2 0 0 0年 6月 1 5日～ 6月 1 8日 )河头 SFD最大值 44.2 1± 4.5 ml/ (cm2 · h) ,纪家 2 9.2± 7.2 ml/ (cm2· h)。此后 ,SFD逐渐减小 ,一直到日落前后降至最低值。树液流在不同的季节具有不同的昼夜节律性变化规律。两地 SF D值的季节波动节律相似 ,湿季时相对较大。但是河头日平均 SFD值 (2 4 36± 1 1 92 .5 ml/ (cm2 · d) )要比纪家 (1 70 3± 82 4 .5 ml/ (cm2 · d) )高 ,这主要是由于两地土壤质地的差异所导致的。在所选时段内 ,SFD的最大值出现在河头的冬季和纪家的夏季 ,这是由于这两天的大气饱和水气压差 ,太阳辐射和土壤有效持水量都比较高的缘故。在空间上 ,从形成层到心材 ,SF D最初有所增加 ,随后持续减小。整个观测期间两地 SFD的极大值均出现在 6月中旬 ,河头为 51 .53ml/ (cm2· h) ,而纪家为 39.85ml/ (cm2 · h) ,显然 ,由于环境条件的限制 。 Sap flux densities (SFD) of two eucalyptus (\%Eucalyptus urophylla\% S. T . Blake) plantations were measured by heat pulse method during September 1999 t o September 2000 at the two study sites, Hetou and Jijia, located in Leizhou Pen insula, Southeast of China. The diurnal and seasonal dynamics of SFD were quantified, and the relationship between SFD and environmental variables were also evaluated. \;We selected four days (between June 15 to 18, 2000, just after rainfall) to study the diurnal fluctuations of SFD. Our data showed that the hourly SFD started to increase at about 7:00 O'clock in the mor ning, peaked at 12:00 (noon), and then decreased gradually towards the early eve ning. The mean maximum hourly rates observed during the study period were 44.21 ±4.5 ml/(cm 2·h) and 29 2±7 2 ml/(cm 2·h) for Hetou and Jijia, respect ively. \;The seasonal patterns of the hourly SFD were similar between two sites, b ut their values were relatively higher during the wetter season. The average dai ly SFD at the Hetou site was 2436 ± 1192 5 ml/(m 2·d), and was signi ficantly higher than that of Jijia, 1703 ± 824 5. The maximum diurnal SFD varied greatly with seasons, but the maximum value appeared in winter at Heto u site, and in summer at Jijia site because of high daily air vapor pressure (da ily VPD) and solar radiation, accompanied with high available soil water content on both dates. \;From the cambium to the heartwood, the SFD value increased at first and t hen decreased continually. \;The extreme maximum value of hourly SFD during the observation period app eared in the middle of June (at 13:00 on 14 June 2000) at the Hetou site, 51 53 ml/(cm 2·h), while this extreme value was 39 85 for the Jijia site (at 13:30 on 15 June 2000) probably due to limited realization of environmental variables . Statistical models were developed to test the relationship between SFD and the environmental factors, such as available soil water content of 4 differe nt depth (50, 150, 250, and 350cm), daily VPD, daily ra

关 键 词： 热脉冲系统 树液流通量 桉树人工林 统计模型

领　　域： [生物学] [农业科学]