尾巨桉樹干液流動態及其影響因子分析1)

王志超　杜阿朋

(國家林業局桉樹研究開發中心，廣東 湛江,524022)

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尾巨桉樹干液流動態及其影響因子分析1)

王志超杜阿朋

(國家林業局桉樹研究開發中心，廣東 湛江,524022)

摘要為了正確認識桉樹的耗水規律，利用熱擴散探針法對2～3年生尾巨桉樹干液流進行連續監測，分析其動態特征，并利用自動氣象站同步測定林分氣象條件，分析各氣象因子與液流的關系。結果表明：2～3年生尾巨桉樹干液流白天變化幅度較大，呈單峰曲線，占全天液流量的85%以上，變化特征與4年生尾巨桉相似，日平均樹干液流密度為5.06 mL·h-1·cm-2較4～6年生尾巨桉日平均液流密度大，夜間液流曲線平坦且較弱，夜晚平均樹干液流密度為1.79 mL·h-1·cm-2是4年生的3.8倍。不同月份間晴天的樹干液流特征存在較大差異。不同天氣條件下，晴天的液流啟動時間最早(7:00)，達到峰值所需時間最短(4.5 h)，且液流峰值最大(18.47 mL·h-1·cm-2)，持續時間最長，日液流量也最大；其次是陰天，最后為雨天。2～3年生尾巨桉樹干液流密度與大氣溫度、風速、太陽輻射、光合有效輻射以及水汽壓虧缺呈極顯著正相關(P<0.01)，與空氣濕度呈極顯著負相關(P<0.01)，相關系數分別為0.468、0.127、0.903、0.909、0.778、-0.626，這與4年生尾巨桉影響因子略有不同；日耗水量與大氣溫度、太陽輻射、光合有效輻射和水汽壓虧缺呈極顯著正相關(P<0.01)，與空氣濕度呈顯著負相關(P<0.05)，相關系數分別為0.489、0.489、0.523、0.408、-0.184。

關鍵詞尾巨桉；樹干液流；環境因子；熱擴散式探針法

分類號S715.2

Characteristics of Stem Sap Flow of Eucalypt and Its Relation to Environmental Factors//

Wang Zhichao, Du Apeng

(China Eucalypt Research Centre, Zhanjiang 524022, P. R. China)//Journal of Northeast Forestry University，2016,44(5)：24-28.

In order to understand eucalyptus water consumption, we used a thermal dissipation probe (TDP) to measure the variation of stem sap flow for 2-3 aEucalyptusurophylla×E.grandis, and analyzed dynamic characteristics. We also measured the environmental factors simultaneously with automatic meteorological station, and analyzed the relationship between various meteorological factors and flow. The stem sap flow varied larger in the daytime, and it was a unimodal curve. It accounted for over 85% of the fluid flow throughout the day. The variation characteristics were similar to 4-aEucalyptusurophylla×E.grandis. The average flow density of trunk was 5.06 mL·h-1·cm-2which was bigger than that of 4-6 a. There were weak sap flow activities in the evening. The change trend of the density of liquid flow was decreased before midnight. Late-night flow density was relatively stable and less than before midnight. The average flow density of trunk was 1.79 mL·h-1·cm-2which was 3.8 times of that of 4 a. There was a big difference between different months about the stem sap flow of it. In different weather conditions, the flow of sunny days start at the earliest time (7:00), and peak time needed for the shortest (4.5 h), and flow peak is the largest (18.47 mL·h-1·cm-2), longest, daily fluid flow is the biggest. The second is the cloudy day followed by a rainy day. The stem sap flow were extremely significantly positive correlation with air temperature, wind speed, solar radiation, photosynthetic available radiation, and vapor pressure deficit (P<0.01), and were very significantly negative correlation with the air humidity (P<0.01), with the correlation coefficients of 0.468, 0.127, 0.903, 0.909, 0.778, and -0.626, respectively, different from those of 4-a. The daily water consumption was extremely significantly positive correlation with atmospheric temperature, solar radiation, photosynthetic available radiation and vapor pressure deficit (P<0.01), and was very significantly negative correlation with the air humidity (P<0.05), with the correlation coefficients of 0.489, 0.489, 0.523, 0.408, and -0.184, respectively.

KeywordsEucalyptus urophylla×E. grandis; Stem sap flow; Environmental factors; Thermal dissipation probe (TDP)

水分是植物生長的主導環境因子之一，不僅影響著植物的個體發育，還是維持森林生態系統平衡的基礎，而蒸騰耗水占植株根部吸收水分的99%以上，是植物吸收水分的主要方式，因此，揭示林木的蒸騰耗水規律是研究林木生長以及森林生態的重要內容之一[1-3]。目前，林木的蒸騰主要利用熱電轉換原理，通過測定林木的樹干液流來計算，并得到國內外很多學者的認可[4-7]。……