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1.
Arundo donax L., commonly known as giant reed, is promising biomass feedstock that is also a notorious invasive plant in freshwater ecosystems around the world. Heretofore, the salt tolerance of A. donax had not been quantified even though anecdotal evidence suggests halophytic qualities. To test whole-plant and leaf level responses, we established a pot experiment on 80 scions propagated from an A. donax population that has naturalized on the shore of the San Francisco Bay Estuary. To quantify growth and physiological responses to salinity (NaCl), A. donax scions were divided into eight treatments and grown for 60 days across a range of salinities (0–42 dS m−1). Classic growth analysis showed >80% reduction in overall growth at the highest salinities. Yet, there was zero mortality indicating that A. donax is able to tolerate high levels of salt. Declining photosynthesis rates were strongly correlated (R2 > 0.97) with decreasing stomatal conductance, which was in turn closely related to increasing salinity. Leaf gas exchange revealed that stomata and leaf limitations of carbon dioxide were three times greater at high salinities. Nonetheless, even when salinities were 38–42 dS m−1 A. donax was able to maintain assimilation rates 7–12 μmol m−2 s−1. Further, by maintaining 50% relative growth at salinities ~12 dS m−1 A. donax can now be classified as ‘moderately salt tolerant’. A. donax leaf gas exchange and whole-plant salt tolerance are greater than many important food crops (i.e. maize, rice), the bioenergy feedstock Miscanthus × giganteus, as well as some uncultivated plant species (i.e. Populus and Salix) that are indigenous in regions A. donax currently invades. The results of this study have implications for both agronomists wishing to expand A. donax to fields dominated by saline soils, and for others who are concerned about the spread of A. donax with altered stream hydrology or sea-level rise. 相似文献
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渗滤液覆盖层灌溉处理对夹竹桃的生理生态效应 总被引:1,自引:0,他引:1
以夹竹桃(Nerium indicum Mill.)作为填埋场覆盖层封场植被材料,历时1a现场研究了有无渗滤液灌溉下夹竹桃生长及其生理生化反应。结果表明,10mm/d渗滤液灌溉下夹竹桃持续生长,生长的快慢呈季节性,且生长较对照组略快;渗滤液灌溉组和对照组夹竹桃丙二醛(MDA)、脯氨酸(Pro)含量的动态变化同气温变化规律相似,超氧化物岐化酶(SOD)、过氧化物酶(POD)活性和抗坏皿酸(AsA)、还原型谷胱甘肽(GSH)含量基本呈季节性波动。盛夏(6—8月份)和秋冬(10-4月份)SOD、POD活性明显提高,AsA、GSH积累显著;1a中渗滤液灌溉组各生理生化指标均较对照组变化辐度大,但两组间差异基本不显著;表明有无渗滤液灌溉下,夹竹桃生理生态反应主要受气候的季节性变化调控,渗滤液灌溉处理不会显著加大对夹竹桃胁迫。 相似文献
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陆地生态系统氮饱和对植物影响的生理生态机制 总被引:20,自引:0,他引:20
由于化石燃料的燃烧、含氮化肥的使用以及畜牧业等人类活动的影响,向大气中排放的含氮化合物数量不断上升,从而引起大气氮沉降的增加,使得某些陆地生态系统出现氮饱和现象。丈章综述了全球氮沉降与陆地生态系统氮饱和现状,探讨了氮饱和对植物光合作用、养分平衡和抗逆性的影响机制。 相似文献
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Restricted use of nitrate and a strong preference for ammonium reflects the nitrogen ecophysiology of a light‐limited red alga 下载免费PDF全文
Daniel W. Pritchard Catriona L. Hurd John Beardall Christopher D. Hepburn 《Journal of phycology》2015,51(2):277-287
Ammonium and nitrate are important sources of inorganic nitrogen for coastal primary producers. Nitrate has higher energy requirement for uptake and assimilation, compared with ammonium, suggesting that it might be a more efficient nitrogen source for slow‐growing, light‐limited macroalgae. To address this hypothesis, we examined the nitrogen ecophysiology of Anotrichium crinitum, a rhodophyte macroalgae common in low‐light habitats in New Zealand. We measured seasonal changes in seawater nitrate and ammonium concentrations and the concentration of nitrate and ammonium stored internally by A. crinitum. We determined the maximal uptake rates of nitrate and ammonium seasonally and grew A. crinitum in the laboratory with these nitrogen sources under two ecologically relevant saturating light levels. Our results show that field‐harvested A. crinitum has a high affinity for ammonium and although it will grow when supplied exclusively with nitrate, internal nitrate pools are low and it is unable to take up nitrate without several days of acclimation to saturating light. Our data predict that A. crinitum would be able to sustain growth with ammonium as the sole source of nitrogen, a strategy that would help it survive under low‐light conditions that prevail in the field. 相似文献
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Characterization of postdive recovery using sound recordings and its relationship to dive duration,exertion, and foraging effort of southern elephant seals (Mirounga leonina) 下载免费PDF全文
Alexandre Génin Gaëtan Richard Joffrey Jouma'a Baptiste Picard Nory El Ksabi Jade Vacquié Garcia Christophe Guinet 《Marine Mammal Science》2015,31(4):1452-1470
It is notoriously difficult to measure physiological parameters in cryptic free‐ranging marine mammals. However, it is critical to understand how marine mammals manage their energy expenditure and their diving behavior in environments where the predation risks are low and where survival is mainly linked to capacities to maintain physiological homeostasis and energy budget balance. Elephant seals are top marine predators that dive deeply and continuously when at sea. Using acoustic recorders deployed on two postbreeding southern elephant seals (SES) females, we developed methods to automatically estimate breathing frequency at the surface. Using this method, we found that seals took successive identical breaths at high frequency (0.29 Hz) when recovering at the surface and that breath count was strongly related to postdive surfacing time. In addition, dive depth was the main factor explaining surfacing time through the effects of dive duration and total underwater swimming effort exerted. Finally, we found that recovery does not only occur over one dive timescale, but over a multidive time scale for one individual. The way these predators manage their recovery will determine how they respond to the change in oceanic water column structure in the future. 相似文献
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Cynthia L. Wright Andr L. A. de Lima Eduardo S. de Souza Jason B. West Bradford P. Wilcox 《Ecology and evolution》2021,11(17):11808
- In seasonally dry tropical forests, plant functional type can be classified as deciduous low wood density, deciduous high wood density, or evergreen high wood density species. While deciduousness is often associated with drought‐avoidance and low wood density is often associated with tissue water storage, the degree to which these functional types may correspond to diverging and unique water use strategies has not been extensively tested.
- We examined (a) tolerance to water stress, measured by predawn and mid‐day leaf water potential; (b) water use efficiency, measured via foliar δ13C; and (c) access to soil water, measured via stem water δ18O.
- We found that deciduous low wood density species maintain high leaf water potential and low water use efficiency. Deciduous high wood density species have lower leaf water potential and variable water use efficiency. Both groups rely on shallow soil water. Evergreen high wood density species have low leaf water potential, higher water use efficiency, and access alternative water sources. These findings indicate that deciduous low wood density species are drought avoiders, with a specialized strategy for storing root and stem water. Deciduous high wood density species are moderately drought tolerant, and evergreen high wood density species are the most drought tolerant group.
- Synthesis. Our results broadly support the plant functional type framework as a way to understand water use strategies, but also highlight species‐level differences.
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A framework for the practical science necessary to restore sustainable,resilient, and biodiverse ecosystems 下载免费PDF全文
Ben P. Miller Elizabeth A. Sinclair Myles H. M. Menz Carole P. Elliott Eric Bunn Lucy E. Commander Emma Dalziell Erica David Belinda Davis Todd E. Erickson Peter J. Golos Siegfried L. Krauss Wolfgang Lewandrowski C. Ellery Mayence Luis Merino‐Martín David J. Merritt Paul G. Nevill Ryan D. Phillips Alison L. Ritchie Sacha Ruoss Jason C. Stevens 《Restoration Ecology》2017,25(4):605-617
Demand for restoration of resilient, self‐sustaining, and biodiverse natural ecosystems as a conservation measure is increasing globally; however, restoration efforts frequently fail to meet standards appropriate for this objective. Achieving these standards requires management underpinned by input from diverse scientific disciplines including ecology, biotechnology, engineering, soil science, ecophysiology, and genetics. Despite increasing restoration research activity, a gap between the immediate needs of restoration practitioners and the outputs of restoration science often limits the effectiveness of restoration programs. Regrettably, studies often fail to identify the practical issues most critical for restoration success. We propose that part of this oversight may result from the absence of a considered statement of the necessary practical restoration science questions. Here we develop a comprehensive framework of the research required to bridge this gap and guide effective restoration. We structure questions in five themes: (1) setting targets and planning for success, (2) sourcing biological material, (3) optimizing establishment, (4) facilitating growth and survival, and (5) restoring resilience, sustainability, and landscape integration. This framework will assist restoration practitioners and scientists to identify knowledge gaps and develop strategic research focused on applied outcomes. The breadth of questions highlights the importance of cross‐discipline collaboration among restoration scientists, and while the program is broad, successful restoration projects have typically invested in many or most of these themes. Achieving restoration ecology's goal of averting biodiversity losses is a vast challenge: investment in appropriate science is urgently needed for ecological restoration to fulfill its potential and meet demand as a conservation tool. 相似文献