کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6541700 | 1421340 | 2018 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
New design of external heat-ratio method for measuring low and reverse rates of sap flow in thin stems
ترجمه فارسی عنوان
طراحی جدید از روش نسبت گرمای خارجی برای اندازه گیری میزان کم و معکوس جریان ساقه در ساقه های نازک
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موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
بوم شناسی، تکامل، رفتار و سامانه شناسی
چکیده انگلیسی
Sap-flow techniques had limited application to thin-stemmed woody and herbaceous species and to diverse functional plant organs until the recent development of the external heat-ratio (EHR) method. Existing EHR techniques using miniature gauge configurations, however, are limited to thin stems with diameters of 2-5â¯mm. This study introduces a new design of an EHR gauge adapted to thin stems with diameters up to 15â¯mm and sap-flux densities <50â¯cmâ¯hâ1. The gauge was calibrated on cut stems of the shrubs Caragana korshinskii and Salix psammophila, with the measured heat-pulse velocity (Vh) compared to gravimetric measurements of sap-flux density (Vs) under controlled conditions. A validation test was also carried out by comparing EHR method with the stem heat-balance (SHB) method through in situ and long-term monitoring of Vs on standing stems of C. korshinskii. Vh in the tested cut stems of both species was linearly correlated with Vs up to approximately 50â¯cmâ¯hâ1 (R2 up to 0.96, Pâ¯<â¯0.001) in a range of stem diameters of 4.1-15.6â¯mm. An empirical multiplier for converting the measured Vh to Vs, however, varied between the two species, 2.02 and 1.15 for C. korshinskii and S. psammophila, respectively. The EHR technique sensitively captured the diurnal dynamics of Vs in field tests, within a range from zero to nearly 30â¯cmâ¯hâ1 on C. korshinskii stems, and hourly Vs was linearly correlated with the reference evapotranspiration (R2â¯=â¯0.70, Pâ¯<â¯0.001) over 26 successive days without drought stress. The tested SHB method, however, poorly detected the sap-flux density, especially at low densities. The gauges for the EHR method were easy to build and capable of accurate estimating bidirectional sap flow, especially at low densities. This technique, with variable EHR gauge configurations, has broader applications than SHB methods for understanding plant-water relations in understories, shrubs and ecosystems dominated by herbage.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Forest Ecology and Management - Volumes 419â420, 1 July 2018, Pages 10-16
Journal: Forest Ecology and Management - Volumes 419â420, 1 July 2018, Pages 10-16
نویسندگان
Sheng Wang, Jun Fan, Jiamin Ge, Qiuming Wang, Chenxu Yong, Wei You,