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Reed CC, Hood SM. Nonstructural carbohydrates explain post-fire tree mortality and recovery patterns. TREE PHYSIOLOGY 2024; 44:tpad155. [PMID: 38123513 DOI: 10.1093/treephys/tpad155] [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: 08/16/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023]
Abstract
Trees use nonstructural carbohydrates (NSCs) to support many functions, including recovery from disturbances. However, NSC's importance for recovery following fire and whether NSC depletion contributes to post-fire delayed mortality are largely unknown. We investigated how fire affects NSCs based on fire-caused injury from a prescribed fire in a young Pinus ponderosa (Lawson & C. Lawson) stand. We assessed crown injury (needle scorch and bud kill) and measured NSCs of needles and inner bark (i.e., secondary phloem) of branches and main stems of trees subject to fire and at an adjacent unburned site. We measured NSCs pre-fire and at six timesteps post-fire (4 days-16 months). While all trees initially survived the fire, NSC concentrations declined quickly in burned trees relative to unburned controls over the same post-fire period. This decline was strongest for trees that eventually died, but those that survived recovered to unburned levels within 14 months post-fire. Two months post-fire, the relationship between crown scorch and NSCs of the main stem inner bark was strongly negative (Adj-R2 = 0.83). Our results support the importance of NSCs for tree survival and recovery post-fire and suggest that post-fire NSC depletion is in part related to reduced photosynthetic leaf area that subsequently limits carbohydrate availability for maintaining tree function. Crown scorch is a commonly measured metric of tree-level fire severity and is often linked to post-fire tree outcome (i.e., recovery or mortality). Thus, our finding that NSC depletion may be the mechanistic link between the fire-caused injury and tree outcome will help improve models of post-fire tree mortality and forest recovery.
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Affiliation(s)
- Charlotte C Reed
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA
- Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Sharon M Hood
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA
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2
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Song HQ, Wang YQ, Yan CL, Zeng WH, Chen YJ, Zhang JL, Liu H, Zhang QM, Zhu SD. Can leaf drought tolerance predict species abundance and its changes in tropical-subtropical forests? TREE PHYSIOLOGY 2023; 43:1319-1325. [PMID: 37154549 DOI: 10.1093/treephys/tpad058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 04/14/2023] [Accepted: 05/01/2023] [Indexed: 05/10/2023]
Abstract
Climate change has resulted in an increase in drought severity in the species-rich tropical and subtropical forests of southern China. Exploring the spatiotemporal relationship between drought-tolerance trait and tree abundance provides a means to elucidate the impact of droughts on community assembly and dynamics. In this study, we measured the leaf turgor loss point (πtlp) for 399 tree species from three tropical forest plots and three subtropical forest plots. The plot area was 1 ha and tree abundance was calculated as total basal area per hectare according to the nearest community census data. The first aim of this study was to explore πtlp abundance relationships in the six plots across a range of precipitation seasonality. Additionally, three of the six plots (two tropical forests and one subtropical forest) had consecutive community censuses data (12-22 years) and the mortality ratios and abundance year slope of tree species were analyzed. The second aim was to examine whether πtlp is a predictor of tree mortality and abundance changes. Our results showed that tree species with lower (more negative) πtlp were more abundant in the tropical forests with relative high seasonality. However, πtlp was not related to tree abundance in the subtropical forests with low seasonality. Moreover, πtlp was not a good predictor of tree mortality and abundance changes in both humid and dry forests. This study reveals the restricted role of πtlp in predicting the response of forests to increasing droughts under climate change.
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Affiliation(s)
- Hui-Qing Song
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
| | - Yong-Qiang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
| | - Chao-Long Yan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
| | - Wen-Hao Zeng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
| | - Ya-Jun Chen
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China
| | - Jiao-Lin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China
| | - Hui Liu
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, Guangdong, China
| | - Qian-Mei Zhang
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, Guangdong, China
- Dinghushan Forest Ecosystem Research Station, South China Botanical Garden, Chinese Academy of Sciences, Zhaoqing 526070, Guangdong, China
| | - Shi-Dan Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
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Partelli-Feltrin R, Smith AMS, Adams HD, Thompson RA, Kolden CA, Yedinak KM, Johnson DM. Death from hunger or thirst? Phloem death, rather than xylem hydraulic failure, as a driver of fire-induced conifer mortality. THE NEW PHYTOLOGIST 2023; 237:1154-1163. [PMID: 36052762 DOI: 10.1111/nph.18454] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Disruption of photosynthesis and carbon transport due to damage to the tree crown and stem cambial cells, respectively, can cause tree mortality. It has recently been proposed that fire-induced dysfunction of xylem plays an important role in tree mortality. Here, we simultaneously tested the impact of a lethal fire dose on nonstructural carbohydrates (NSCs) and xylem hydraulics in Pinus ponderosa saplings. Saplings were burned with a known lethal fire dose. Nonstructural carbohydrates were assessed in needles, main stems, roots and whole plants, and xylem hydraulic conductivity was measured in the main stems up to 29 d postfire. Photosynthesis and whole plant NSCs declined postfire. Additionally, all burned saplings showed 100% phloem/cambium necrosis, and roots of burned saplings had reduced NSCs compared to unburned and defoliated saplings. We further show that, contrary to patterns observed with NSCs, water transport was unchanged by fire and there was no evidence of xylem deformation in saplings that experienced a lethal dose of heat from fire. We conclude that phloem and cambium mortality, and not hydraulic failure, were probably the causes of death in these saplings. These findings advance our understanding of the physiological response to fire-induced injuries in conifer trees.
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Affiliation(s)
| | - Alistair M S Smith
- Department of Forest, Rangeland, and Fire Sciences, University of Idaho, Moscow, ID, 83844, USA
- Department of Earth and Spatial Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Henry D Adams
- School of Environment, Washington State University, Pullman, WA, 99164-2812, USA
| | - R Alex Thompson
- School of Environment, Washington State University, Pullman, WA, 99164-2812, USA
| | - Crystal A Kolden
- Gallo School of Management, University of California Merced, Merced, CA, 95343, USA
| | - Kara M Yedinak
- US Forest Service Research and Development, Madison, WI, 53726-2366, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
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Li M, Guo X, Liu L, Liu J, Du N, Guo W. Responses to defoliation of Robinia pseudoacacia L. and Sophora japonica L. are soil water condition dependent. ANNALS OF FOREST SCIENCE 2022; 79:18. [DOI: 10.1186/s13595-022-01136-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/03/2022] [Indexed: 06/14/2024]
Abstract
Abstract
Key message
Defoliation significantly affected biomass allocation of Robinia pseudoacacia L. and Sophora japonica L., but leaf physiology readjusted to control levels at the end of the experiment. Considering carbon or sink limitation and relative height growth rate, defoliated R. pseudoacacia grew faster than S. japonica under well-watered conditions, while defoliated S. japonica and R. pseudoacacia had similar performance under drought conditions.
Context
Climate change may result in increases of both drought intensity and insect survival, thereby affecting both exotic and native trees in warm temperate forests.
Aims
In this study, we examined the interaction effects of defoliation and drought on an exotic species Robinia pseudoacacia and a native species Sophora japonica in a warm temperate area, to provide a theoretical basis for predicting the distribution and dynamics of the two species under future climate change.
Methods
In a greenhouse, both species were exposed to three soil moisture (75%, 55%, and 35% of field capacity) and three defoliation treatments (no defoliation, 50% defoliation, and 100% defoliation). Leaf physiology, biomass, and non-structural carbohydrate were determined.
Results
Leaf physiology of defoliated trees did not differ from controls trees, but defoliated seedlings allocated relatively more resources to the leaves at the end of the experiment. In well-watered conditions, defoliated R. pseudoacacia was not carbon or sink limited and defoliated S. japonica was carbon limited, while defoliated individuals of the two species were sink limited under drought. Defoliated R. pseudoacacia grow more rapidly than S. japonica in well-watered conditions. Defoliated R. pseudoacacia had a similar growth rate to S. japonica in drought.
Conclusions
Defoliation clearly affects biomass allocation of the two species, but not leaf physiology. Considering the carbon or sink limitation, the growth of S. japonica and R. pseudoacacia may be limited by future global climate change scenarios.
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Geisler M, Buerki S, Serpe MD. Herbivory Amplifies Adverse Effects of Drought on Seedling Recruitment in a Keystone Species of Western North American Rangelands. PLANTS (BASEL, SWITZERLAND) 2022; 11:2628. [PMID: 36235494 PMCID: PMC9573362 DOI: 10.3390/plants11192628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/01/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Biotic interactions can affect a plant's ability to withstand drought. Such an effect may impact the restoration of the imperiled western North American sagebrush steppe, where seedlings are exposed to summer drought. This study investigated the impact of herbivory on seedlings' drought tolerance for a keystone species in this steppe, the shrub Artemisia tridentata. Herbivory effects were investigated in two field experiments where seedlings were without tree protectors or within plastic or metal-mesh tree protectors. Treatment effects were statistically evaluated on herbivory, survival, leaf water potential, and inflorescence development. Herbivory occurrence was 80% higher in seedlings without protectors. This damage occurred in early spring and was likely caused by ground squirrels. Most plants recovered, but herbivory was associated with higher mortality during the summer when seedlings experienced water potentials between -2.5 and -7 MPa. However, there were no differences in water potential between treatments, suggesting that the browsed plants were less tolerant of the low water potentials experienced. Twenty months after outplanting, the survival of plants without protectors was 40 to 60% lower than those with protectors. The percentage of live plants developing inflorescences was approximately threefold higher in plants with protectors. Overall, spring herbivory amplified susceptibility to drought and delayed reproductive development.
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Wang YQ, Ni MY, Zeng WH, Huang DL, Xiang W, He PC, Ye Q, Cao KF, Zhu SD. Co-ordination between leaf biomechanical resistance and hydraulic safety across 30 sub-tropical woody species. ANNALS OF BOTANY 2021; 128:183-191. [PMID: 33930116 PMCID: PMC8324032 DOI: 10.1093/aob/mcab055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/24/2021] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Leaf biomechanical resistance protects leaves from biotic and abiotic damage. Previous studies have revealed that enhancing leaf biomechanical resistance is costly for plant species and leads to an increase in leaf drought tolerance. We thus predicted that there is a functional correlation between leaf hydraulic safety and biomechanical characteristics. METHODS We measured leaf morphological and anatomical traits, pressure-volume parameters, maximum leaf hydraulic conductance (Kleaf-max), leaf water potential at 50 % loss of hydraulic conductance (P50leaf), leaf hydraulic safety margin (SMleaf), and leaf force to tear (Ft) and punch (Fp) of 30 co-occurring woody species in a sub-tropical evergreen broadleaved forest. Linear regression analysis was performed to examine the relationships between biomechanical resistance and other leaf hydraulic traits. KEY RESULTS We found that higher Ft and Fp values were significantly associated with a lower (more negative) P50leaf and a larger SMleaf, thereby confirming the correlation between leaf biomechanical resistance and hydraulic safety. However, leaf biomechanical resistance showed no correlation with Kleaf-max, although it was significantly and negatively correlated with leaf outside-xylem hydraulic conductance. In addition, we also found that there was a significant correlation between biomechanical resistance and the modulus of elasticity by excluding an outlier. CONCLUSIONS The findings of this study reveal leaf biomechanical-hydraulic safety correlation in sub-tropical woody species.
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Affiliation(s)
- Yong-Qiang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Ming-Yuan Ni
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Wen-Hao Zeng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Dong-Liu Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Wei Xiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Peng-Cheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
| | - Shi-Dan Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Nanning, Guangxi, China
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Wang Z, Zhou Z, Wang C. Defoliation-induced tree growth declines are jointly limited by carbon source and sink activities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143077. [PMID: 33131880 DOI: 10.1016/j.scitotenv.2020.143077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/12/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Defoliation resulting from herbivory, storm, drought, and frost may seriously impair tree growth and forest production. However, a comprehensive evaluation of defoliation impacts on tree carbon (C) assimilation and growth has not been conducted. We performed a meta-analysis of a dataset that included 1562 observations of 40 tree species from 50 studies worldwide, and evaluated defoliation impacts on photosynthetic capacity, C allocation, and tree growth. Our results showed that the reduced tree-level leaf area by defoliation outweighed the enhanced leaf-level photosynthesis, leading to a net reduction in tree C assimilation that was accompanied with decreases in nonstructural carbohydrates (NSCs) concentrations. The negative effects of defoliation on leaf NSCs decreased over time, but leaf production increased following defoliation, suggesting a shift in the C allocation towards shoots over roots. Defoliation intensity negatively affected tree growth, but post-defoliated recovery time did oppositely. The structure equation modelling showed that defoliation reduced tree growth mainly by indirectly reducing C assimilation (r = -0.4), and minorly by direct negative effect of defoliation intensity (r = -0.28) and positive effect of post-defoliated time (r = 0.33). These findings suggest that tree growth declines caused by defoliation are co-limited by C-source and sink activities, which provide a physiological basis of tree growth that is of significance in tree growth modelling and forest management under global changes.
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Affiliation(s)
- Zhaoguo Wang
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management - Ministry of Education, Northeast Forestry University, Harbin 150040, China
| | - Zhenghu Zhou
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management - Ministry of Education, Northeast Forestry University, Harbin 150040, China
| | - Chuankuan Wang
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management - Ministry of Education, Northeast Forestry University, Harbin 150040, China.
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Chen Z, Zhu S, Zhang Y, Luan J, Li S, Sun P, Wan X, Liu S. Tradeoff between storage capacity and embolism resistance in the xylem of temperate broadleaf tree species. TREE PHYSIOLOGY 2020; 40:1029-1042. [PMID: 32310276 DOI: 10.1093/treephys/tpaa046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Xylem traits are critical plant functional traits associated with water transport, mechanical support, and carbohydrate and water storage. Studies on the xylem hydraulic efficiency-safety tradeoff are numerous; however, the storage function of xylem parenchyma is rarely considered. The effects of a substantial number of xylem traits on water transport, embolism resistance, mechanical support, storage capacity and nonstructural carbohydrate (NSC) content were investigated in 19 temperate broadleaf species planted in an arid limestone habitat in northern China. There was no xylem hydraulic efficiency-safety tradeoff in the 19 broadleaf species. The total parenchyma fraction was negatively correlated with the fiber fraction. Embolism resistance was positively correlated with indicators of xylem mechanical strength such as vessel wall reinforcement, vessel wall thickness and fiber wall thickness, and was negatively related to the axial parenchyma fraction, especially the paratracheal parenchyma fraction. The paratracheal parenchyma fraction was positively correlated with the ratio of the paratracheal parenchyma fraction to the vessel fraction. In addition, the xylem NSC concentration was positively related to the total parenchyma fraction and axial parenchyma fraction. There was a storage capacity-embolism resistance tradeoff in the xylem of 19 broadleaf species in arid limestone habitats. We speculate that the temperate broadleaf species may show a spectrum of xylem hydraulic strategies, from the embolism resistance strategy related to a more negative P50 (the water potential corresponding to 50% loss of xylem conductivity) to the embolization repair strategy based on more paratracheal parenchyma.
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Affiliation(s)
- Zhicheng Chen
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
| | - Yongtao Zhang
- Mountain Tai Forest Ecosystem Research Station of National Forestry and Grassland Administration, Forestry College of Shandong Agricultural University, Taian 271018, China
| | - Junwei Luan
- Key Laboratory of Bamboo and Rattan Science and Technology, Institute for Resources and Environment, International Centre for Bamboo and Rattan, National Forestry and Grassland Administration, Beijing 100102, China
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
| | - Pengsen Sun
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - Xianchong Wan
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
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Gomez-Gallego M, Williams N, Leuzinger S, Scott PM, Bader MKF. No carbon limitation after lower crown loss in Pinus radiata. ANNALS OF BOTANY 2020; 125:955-967. [PMID: 31990290 PMCID: PMC7218809 DOI: 10.1093/aob/mcaa013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND AIMS Biotic and abiotic stressors can cause different defoliation patterns within trees. Foliar pathogens of conifers commonly prefer older needles and infection with defoliation that progresses from the bottom crown to the top. The functional role of the lower crown of trees is a key question to address the impact of defoliation caused by foliar pathogens. METHODS A 2 year artificial defoliation experiment was performed using two genotypes of grafted Pinus radiata to investigate the effects of lower-crown defoliation on carbon (C) assimilation and allocation. Grafts received one of the following treatments in consecutive years: control-control, control-defoliated, defoliated-control and defoliated-defoliated. RESULTS No upregulation of photosynthesis either biochemically or through stomatal control was observed in response to defoliation. The root:shoot ratio and leaf mass were not affected by any treatment, suggesting prioritization of crown regrowth following defoliation. In genotype B, defoliation appeared to impose C shortage and caused reduced above-ground growth and sugar storage in roots, while in genotype A, neither growth nor storage was altered. Root C storage in genotype B decreased only transiently and recovered over the second growing season. CONCLUSIONS In genotype A, the contribution of the lower crown to the whole-tree C uptake appears to be negligible, presumably conferring resilience to foliar pathogens affecting the lower crown. Our results suggest that there is no C limitation after lower-crown defoliation in P. radiata grafts. Further, our findings imply genotype-specific defoliation tolerance in P. radiata.
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Affiliation(s)
- Mireia Gomez-Gallego
- New Zealand Forest Research Institute (Scion), 49 Sala Street, Te Papa Tipu Innovation Park, Private Bag 3020, Rotorua, New Zealand
- Institute for Applied Ecology New Zealand, School of Sciences, Auckland University of Technology, 31–33 Symonds Street, Auckland, New Zealand
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Nari Williams
- New Zealand Forest Research Institute (Scion), 49 Sala Street, Te Papa Tipu Innovation Park, Private Bag 3020, Rotorua, New Zealand
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 1401, Havelock North, New Zealand
| | - Sebastian Leuzinger
- Institute for Applied Ecology New Zealand, School of Sciences, Auckland University of Technology, 31–33 Symonds Street, Auckland, New Zealand
| | - Peter Matthew Scott
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 1401, Havelock North, New Zealand
| | - Martin Karl-Friedrich Bader
- Institute for Applied Ecology New Zealand, School of Sciences, Auckland University of Technology, 31–33 Symonds Street, Auckland, New Zealand
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Smith MG, Arndt SK, Miller RE, Kasel S, Bennett LT. Trees use more non-structural carbohydrate reserves during epicormic than basal resprouting. TREE PHYSIOLOGY 2018; 38:1779-1791. [PMID: 30219862 DOI: 10.1093/treephys/tpy099] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 08/21/2018] [Indexed: 06/08/2023]
Abstract
Non-structural carbohydrates (NSCs) are crucial to support tree resprouting after disturbances that damage the crown or stem. Epicormic resprouting (from stem) could demand more from NSC reserves than basal resprouting (following top-kill), since epicormically resprouting trees need to maintain a greater living biomass. Yet, little is known about NSC use during epicormic resprouting, particularly the relative importance of stem and below-ground NSC reserves. We compared the distribution and magnitude of NSC decreases during epicormic and basal resprouting by experimentally removing crowns or stems of 14-year-old Eucalyptus obliqua L'Hér. trees in native forest, then harvesting these trees over a 10-month period (start, sprouts emerged, sprouts expanded) to measure changes in NSC concentration and mass by organ (stem, lignotuber, roots). We hypothesized that (i) NSC depletion during resprouting is primarily due to decreases in starch rather than soluble sugars concentrations; (ii) during epicormic resprouting, stem NSC concentrations are decreased irrespective of any decreases in roots; and (iii) absolute decreases in NSC mass are greater for epicormic than basal resprouting during the leafless period due to the carbon demands associated with maintaining greater living biomass. Results confirmed our hypotheses; starch was the primary storage carbohydrate, stems were an important source of starch during epicormic resprouting and carbon demands of maintenance functions were greater for epicormic resprouting, leading to greater decreases in NSC reserves. Roots were a more important starch storage organ than the lignotuber for both epicormic and basal resprouting. The proportional decrease in starch was severe for both modes of resprouting due to a long leafless period, after which trees resprouting epicormically relied on starch reserves for longer than those resprouting basally. It remains to be seen how the timing of disturbance affects the timing and vigour of resprouting, and how long-term NSC recovery differs for epicormic and basal resprouting.
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Affiliation(s)
- Merryn G Smith
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, Australia
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, Australia
| | - Rebecca E Miller
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, Australia
| | - Sabine Kasel
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, Australia
| | - Lauren T Bennett
- School of Ecosystem and Forest Sciences, The University of Melbourne, 4 Water Street, Creswick, Victoria, Australia
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