植物生态学报
植物生態學報
식물생태학보
ACTA PHYTOECOLOGICA SINICA
2010年
5期
535-546
,共12页
陈立欣%张志强%李湛东%张文娟%张晓放%董克宇%王国玉
陳立訢%張誌彊%李湛東%張文娟%張曉放%董剋宇%王國玉
진립흔%장지강%리담동%장문연%장효방%동극우%왕국옥
环境因子%夜间液流%热扩散液流测定技术%城市树种
環境因子%夜間液流%熱擴散液流測定技術%城市樹種
배경인자%야간액류%열확산액류측정기술%성시수충
environmental variables%nighttime sap flow%thermal dissipation probe (TDP)%urban trees
夜间液流有助于树木物质运输及其体内水分的补充(water recharge),它不仅对植物的生长发育具有重要的生理生态学意义,而且对大尺度植物蒸腾耗水的估算可能产生重要影响.2008年6月1日至8月31日,以热扩散探针(thermal dissipation probe,TDP)技术对大连市劳动公园内的雪松(Cedrus deodara)、大叶榉(Zelkova schneideriana)、丝棉木(Euonymus bungeanus)和水杉(Metasequoia glyptostroboides)4种乔木树种的不同径阶样木树干边材液流进行了测定,并结合同步土壤水分与小气候观测结果分析了树木夜间(18:00至次日15:00)液流特征.实验结果表明,树木普遍存在可感夜间液流,夜间液流总量占观测期液流总量的比例在样木个体间呈现显著差异,其变化范围为0.44%-75.96%;观测期雨天夜间液流波动活跃,显著高于晴天,其单日夜间液流总量可持平,甚至高于日间液流.相关分析表明:水汽压亏缺(vapor pressure deficit,VPD)和风速的变化与夜间蒸腾显著相关,它们能够较好地解释液流变化(R~2>0.6);树木夜间液流主要用于夜间蒸腾和自身水分补充,夜间液流现象主要发生在前半夜,后半夜液流平稳且极接近0,夜间液流量与相应的日间流量(R~2=0.356,P=0.00)及胸径这(R~2_(Spearman)>0.80)显著相关.说明植物本身的结构和生理特点也是影响树木夜间液流的重要因子.单株样木夜间液流占全天总蒸腾量的比例低于14.4%,如不考虑夜间液流的影响,根据日间液流通过尺度扩展推算的森林生态系统年蒸腾量可能偏低.
夜間液流有助于樹木物質運輸及其體內水分的補充(water recharge),它不僅對植物的生長髮育具有重要的生理生態學意義,而且對大呎度植物蒸騰耗水的估算可能產生重要影響.2008年6月1日至8月31日,以熱擴散探針(thermal dissipation probe,TDP)技術對大連市勞動公園內的雪鬆(Cedrus deodara)、大葉櫸(Zelkova schneideriana)、絲棉木(Euonymus bungeanus)和水杉(Metasequoia glyptostroboides)4種喬木樹種的不同徑階樣木樹榦邊材液流進行瞭測定,併結閤同步土壤水分與小氣候觀測結果分析瞭樹木夜間(18:00至次日15:00)液流特徵.實驗結果錶明,樹木普遍存在可感夜間液流,夜間液流總量佔觀測期液流總量的比例在樣木箇體間呈現顯著差異,其變化範圍為0.44%-75.96%;觀測期雨天夜間液流波動活躍,顯著高于晴天,其單日夜間液流總量可持平,甚至高于日間液流.相關分析錶明:水汽壓虧缺(vapor pressure deficit,VPD)和風速的變化與夜間蒸騰顯著相關,它們能夠較好地解釋液流變化(R~2>0.6);樹木夜間液流主要用于夜間蒸騰和自身水分補充,夜間液流現象主要髮生在前半夜,後半夜液流平穩且極接近0,夜間液流量與相應的日間流量(R~2=0.356,P=0.00)及胸徑這(R~2_(Spearman)>0.80)顯著相關.說明植物本身的結構和生理特點也是影響樹木夜間液流的重要因子.單株樣木夜間液流佔全天總蒸騰量的比例低于14.4%,如不攷慮夜間液流的影響,根據日間液流通過呎度擴展推算的森林生態繫統年蒸騰量可能偏低.
야간액류유조우수목물질운수급기체내수분적보충(water recharge),타불부대식물적생장발육구유중요적생리생태학의의,이차대대척도식물증등모수적고산가능산생중요영향.2008년6월1일지8월31일,이열확산탐침(thermal dissipation probe,TDP)기술대대련시노동공완내적설송(Cedrus deodara)、대협거(Zelkova schneideriana)、사면목(Euonymus bungeanus)화수삼(Metasequoia glyptostroboides)4충교목수충적불동경계양목수간변재액류진행료측정,병결합동보토양수분여소기후관측결과분석료수목야간(18:00지차일15:00)액류특정.실험결과표명,수목보편존재가감야간액류,야간액류총량점관측기액류총량적비례재양목개체간정현현저차이,기변화범위위0.44%-75.96%;관측기우천야간액류파동활약,현저고우청천,기단일야간액류총량가지평,심지고우일간액류.상관분석표명:수기압우결(vapor pressure deficit,VPD)화풍속적변화여야간증등현저상관,타문능구교호지해석액류변화(R~2>0.6);수목야간액류주요용우야간증등화자신수분보충,야간액류현상주요발생재전반야,후반야액류평은차겁접근0,야간액류량여상응적일간류량(R~2=0.356,P=0.00)급흉경저(R~2_(Spearman)>0.80)현저상관.설명식물본신적결구화생리특점야시영향수목야간액류적중요인자.단주양목야간액류점전천총증등량적비례저우14.4%,여불고필야간액류적영향,근거일간액류통과척도확전추산적삼림생태계통년증등량가능편저.
Aims Nocturnal sap flow is a driving force not only for chemical transport and nutrient movement within trees, but also for water recharge caused by diurnal transpiration loss. Therefore, it is both ecologically and physiologi-cally significant for estimating tree and stand transpiration at larger spatial and longer temporal scales. Our objec-tive was to analyze nocturnal sap flow (18:00-5:00 next morning) and its biophysical controls in four tree species (Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides) in Laodong Park in Dalian, China.Methods During June 1-August 31,2008, we measured sap flow of twelve urban trees of four species and three diameter at breast height (DBH) classes of each species continuously by thermal dissipation probes, soil moisture by ECH2O soil moisture probe and microclimate data by an automatic weather station. SPSS 13.0 was used for statistical analysis of sap flow and environmental factors.Important findings Nocturnal sap flow was measured in all sampled trees, but varied from 0.44% to 75.96% of total daily water consumption. Nocturnal flow was larger and more active on rainy days than that on sunny ones, to the extent that it equaled or exceeded the diurnal volume. Vapor pressure deficit and wind speed were signifi-cantly correlated with nocturnal water movement (R~2 > 0.6), which could provide an explanation for nocturnal transpiration. Nocturnal sap flow mainly contributed to nocturnal transpiration and water recharge. It peaked be-fore midnight and dropped to nearly zero afterwards. Furthermore, nocturnal sap flow was remarkably correlated with diurnal sap flow (R~2 = 0.356, p = 0.00) and DBH (R~2_(Spearman)> 0.80), substantiating the important role of spe-cific structural and physiological characteristics. Nocturnal sap flow of individuals accounted for an average of < 14.4% of the total transpiration volume. Total water consumption of a forest ecosystem scaled up by daytime sap flux measurements can be underestimated without integration of nocturnal sap flux.