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Kumar M, Joseph G, Bhutia Y, Krishnaswamy J. Contrasting sap flow characteristics between pioneer and late-successional tree species in secondary tropical montane forests of Eastern Himalaya, India. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5273-5293. [PMID: 37290031 PMCID: PMC10498023 DOI: 10.1093/jxb/erad207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 05/30/2023] [Indexed: 06/10/2023]
Abstract
The interactive role of life-history traits and environmental factors on plant water relations is crucial for understanding the responses of species to climate change, but it remains poorly understood in secondary tropical montane forests (TMFs). In this study, we examined differences in sap flow between the pioneer species Symplocos racemosa and Eurya acuminata, and the late-successional species Castanopsis hystrix that co-occur in a biodiverse Eastern Himalayan secondary broadleaved TMF. The fast-growing pioneers had sap flux densities that were 1.6-2.1 times higher than the late-successional species, and exhibited characteristics of long-lived pioneer species. Significant radial and azimuthal variability in sap flow (V) between species was observed and could be attributed to the life-history trait and the access of the canopy to sunlight. Nocturnal V was 13.8% of the daily total and was attributable to stem recharge during the evening period (18.00-23.00 h) and to endogenous stomatal controls during the pre-dawn period (00.00-05.00 h). The shallow-rooted pioneer species both exhibited midday depression in V that was attributable to photosensitivity and diel moisture stress responses. In contrast, the deep-rooted late-successional species showed unaffected transpiration across the dry season, indicating their access to groundwater. Thus, our results suggest that secondary broadleaved TMFs, with a dominance of shallow-rooted pioneers, are more prone to the negative impacts of drier and warmer winters than primary forests, which are dominated by deep-rooted species. Our study provides an empirical understanding of how life-history traits coupled with microclimate can modulate plant water use in the widely distributed secondary TMFs in Eastern Himalaya, and highlights their vulnerability to warmer winters and reduced winter precipitation due to climate change.
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Affiliation(s)
- Manish Kumar
- Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore 560064, Karnataka, India
- Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka, India
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Gladwin Joseph
- Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore 560064, Karnataka, India
- Conservation Biology Institute, Corvallis, Oregon 97333, USA
| | - Yangchenla Bhutia
- Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore 560064, Karnataka, India
- Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka, India
- Sikkim State Council of Science & Technology, Gangtok 737102, Sikkim, India
| | - Jagdish Krishnaswamy
- Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore 560064, Karnataka, India
- Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka, India
- School of Environment and Sustainability, Indian Institute for Human Settlements, Bangalore 560080, Karnataka, India
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Pasqualotto G, Carraro V, Menardi R, Anfodillo T. Calibration of Granier-Type (TDP) Sap Flow Probes by a High Precision Electronic Potometer. SENSORS 2019; 19:s19102419. [PMID: 31137901 PMCID: PMC6566514 DOI: 10.3390/s19102419] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/15/2019] [Accepted: 05/24/2019] [Indexed: 01/29/2023]
Abstract
Thermal dissipation probe (TDP) method (Granier, 1985) is widely used to estimate tree transpiration (i.e., the water evaporated from the leaves) because it is simple to build, easy to install, and relatively inexpensive. However, the universality of the original calibration has been questioned and, in many cases, proved to be inaccurate. Thus, when the TDP is used in a new species, specific tests should be carried out. Our aim was to propose a new method for improving the accuracy of TDP on trees in the field. Small hazelnut trees (diameter at breast height 5 cm) were used for the experiment. The response of TDP sensors was compared with a reference water uptake measured with an electronic potometer system provided with a high precision liquid flow meter. We equipped three stems where we measured the sap flow density, the sapwood area (by using fuchsine), the total tree water uptake (reference), and the main meteorological parameters during summer 2018. Results confirmed that the original Granier’s calibration underestimated the effective tree transpiration (relative error about −60%). We proposed a new equation for improving the measurement accuracy within an error of about 4%. The system proposed appeared an easier solution compared to potted trees and particularly suitable for orchards, thus contributing to improve the irrigation management worldwide.
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Affiliation(s)
- Gaia Pasqualotto
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli studi di Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
| | - Vinicio Carraro
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli studi di Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
| | - Roberto Menardi
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli studi di Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
| | - Tommaso Anfodillo
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli studi di Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
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Hölttä T, Dominguez Carrasco MDR, Salmon Y, Aalto J, Vanhatalo A, Bäck J, Lintunen A. Water relations in silver birch during springtime: How is sap pressurised? PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20:834-847. [PMID: 29732663 DOI: 10.1111/plb.12838] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
Positive sap pressures are produced in the xylem of birch trees in boreal conditions during the time between the thawing of the soil and bud break. During this period, xylem embolisms accumulated during wintertime are refilled with water. The mechanism for xylem sap pressurization and its environmental drivers are not well known. We measured xylem sap flow, xylem sap pressure, xylem sap osmotic concentration, xylem and whole stem diameter changes, and stem and root non-structural carbohydrate concentrations, along with meteorological conditions at two sites in Finland during and after the sap pressurisation period. The diurnal dynamics of xylem sap pressure and sap flow during the sap pressurisation period varied, but were more often opposite to the diurnal pattern after bud burst, i.e. sap pressure increased and sap flow rate mostly decreased when temperature increased. Net conversion of soluble sugars to starch in the stem and roots occurred during the sap pressurisation period. Xylem sap osmotic pressure was small in comparison to total sap pressure, and it did not follow changes in environmental conditions or tree water relations. Based on these findings, we suggest that xylem sap pressurisation and embolism refilling occur gradually over a few weeks through water transfer from parenchyma cells to xylem vessels during daytime, and then the parenchyma are refilled mostly during nighttime by water uptake from soil. Possible drivers for water transfer from parenchyma cells to vessels are discussed. Also the functioning of thermal dissipation probes in conditions of changing stem water content is discussed.
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Affiliation(s)
- T Hölttä
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - M D R Dominguez Carrasco
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Y Salmon
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Department of Physics, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - J Aalto
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Hyytiälä Forestry Station, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - A Vanhatalo
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - J Bäck
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - A Lintunen
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Department of Physics, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
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