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Sun JWC, Sharifi MR, Rundel PW. Plasticity in Compensatory Growth to Artificial Defoliation and Light Availability in Four Neotropical Understory and Forest Edge Herb Species. Biology (Basel) 2022; 11:biology11101532. [PMID: 36290435 PMCID: PMC9598688 DOI: 10.3390/biology11101532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 09/30/2022] [Accepted: 10/14/2022] [Indexed: 11/07/2022]
Abstract
Defoliation from falling branches is a major factor in the survival of understory herbs in tropical rainforests. Experimental studies of defoliation under three levels of light environment compared responses to partial and total defoliation in four species of tropical rainforest understory herbs. We predicted that elevated levels of light availability would help compensate for damage to through compensatory growth in both understory and forest edge species and that forest edge species would more effectively compensate under high light conditions than shade-tolerant species from the forest understory All species showed a high tolerance to defoliation under high and intermediate light conditions. Under low-light conditions survival differed dramatically with minimal mortality in forest-edge species compared to high mortality in completely defoliated understory species. Defoliation, and light × defoliation interactions, impacted multiple growth traits in understory species. In contrast, forest-edge species showed no effect of defoliation except on total biomass, and only one light × defoliation interaction was observed. Our results indicate that differences in biomass allocation, leaf ecophysiology, and other growth parameters between forest understory and edge species may be structuring post-damage response in understory and forest edge herbs.
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Rundel PW, Cooley AM, Gerst KL, Riordan EC, Sharifi MR, Sun JW, Tower JA. Functional traits of broad-leaved monocot herbs in the understory and forest edges of a Costa Rican rainforest. PeerJ 2020; 8:e9958. [PMID: 33194368 PMCID: PMC7597634 DOI: 10.7717/peerj.9958] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 08/25/2020] [Indexed: 12/03/2022] Open
Abstract
Broad-leaved monocot herbs are widespread and dominant components of the shaded understories of wet neotropical forests. These understory habitats are characterized by light limitation and a constant threat of falling branches. Many shaded understory herb species have close relatives that occupy forest edges and gaps, where light availability is higher and defoliation threat is lower, creating an opportunity for comparative analysis of functional traits in order to better understand the evolutionary adaptations associated with this habitat transition. We documented ecological, morphological and ecophysiological traits of multiple herb species in six monocot families from each of these two habitats in the wet tropical rainforest at the La Selva Biological Station, Costa Rica. We found that a mixture of phylogenetic canalization and ecological selection for specific habitats helped explain patterns of functional traits. Understory herbs were significantly shorter and had smaller leaves than forest edge species. Although the mean number of leaves per plant and specific leaf area did not differ between the two groups, the larger leaf size of forest edge species gave them more than three times the mean plant leaf area. Measures of leaf water content and nitrogen content varied within both groups and mean values were not significantly different. Despite the high leaf nitrogen contents, the maximum photosynthetic rates of understory herbs were quite low. Measures of δ13C as an analog of water use efficiency found significantly lower (more negative) values in understory herbs compared to forest edge species. Clonality was strongly developed in several species but did not show strong phylogenetic patterns. This study highlights many functional traits that differ between broad-leaved monocot species characteristic of understory and forest edge habitats, as well as traits that vary primarily by phylogenetic relatedness. Overall, plant functional traits do not provide a simple explanation for the relative differences in abundance for individual understory and forest edge species with some occurring in great abundance while others are relatively rare.
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Affiliation(s)
- Philip W Rundel
- Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, United States of America
| | - Arielle M Cooley
- Biology, Whitman College, Walla Walla, WA, United States of America
| | - Katharine L Gerst
- USA National Phenlogical Network, University of Arizona, Tucson, AZ, United States of America
| | - Erin C Riordan
- Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ, United States of America
| | - M Rasoul Sharifi
- Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, United States of America
| | - Jennifer W Sun
- Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, United States of America
| | - J Alexandra Tower
- Biology, Santa Monica College, Santa Monica, CA, United States of America
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Valliere JM, Escobedo EB, Bucciarelli GM, Sharifi MR, Rundel PW. Invasive annuals respond more negatively to drought than native species. New Phytol 2019; 223:1647-1656. [PMID: 31004498 DOI: 10.1111/nph.15865] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
In his foundational list of 'ideal weed' characteristics, Baker (1965) proposed that weedy plants maximize reproductive output under high resource availability. Since then, the idea that invasive plant species are more responsive to fluctuating resources compared with native or noninvasive species has gained considerable traction, although few studies extend this hypothesis to include reproductive output. We revisit Baker's hypothesis in the context of invasion and drought in California grasslands, exploring whether invasives show greater growth and reproductive responses to water availability compared with the native wildflowers they displace. In an outdoor potted study, we grew eight native and eight invasive species of annuals commonly found in southern California grasslands to reproductive maturity under both well-watered and drought conditions. While drought negatively impacted plant performance overall, invasives showed more negative responses for growth and reproductive traits. Invasives also grew larger than native species, especially under well-watered conditions, and produced seed with higher rates of germination. Invasives may be more negatively impacted by drought compared with natives, but they are also able to capitalize on high resource conditions and greatly increase reproductive output. Such opportunistic responses exhibited by invasives might explain previously observed fluctuations in their abundance under variable precipitation.
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Affiliation(s)
- Justin M Valliere
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, University of California, Los Angeles, CA, 90095, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
| | - Evelin B Escobedo
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
| | - Gary M Bucciarelli
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
| | - M Rasoul Sharifi
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
| | - Philip W Rundel
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
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Valliere JM, Zhang J, Sharifi MR, Rundel PW. Can we condition native plants to increase drought tolerance and improve restoration success? Ecol Appl 2019; 29:e01863. [PMID: 30831005 DOI: 10.1002/eap.1863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/28/2018] [Accepted: 01/07/2019] [Indexed: 06/09/2023]
Abstract
A common method in ecological restoration is the transplanting of nursery-grown seedlings to the field and, with proper resources, this technique can be highly successful. However, stressors such as drought may negatively impact plant performance and restoration success, especially in dryland ecosystems. Furthermore, increasing environmental change may hamper the ability of practitioners to restore native vegetation. A growing body of research suggests that exposing plants to a stressor may improve tolerance to subsequent stress events later in life. We sought to understand if such a phenomenon could be exploited in order to improve plant drought-tolerance and aid native plant restoration in southern California. In a multi-phase experiment, we first exposed seedlings of native perennials to episodic drought and then later compared the response of these plants to a second drought event to that of well-watered controls. We also transplanted replicates of both treatments to a restoration site in the field to test whether exposure to drought as a seedling could improve plant performance. Plant species responded to drought differently, with species exhibiting the full range of positive, neutral, and negative responses to temporal variability in water stress. However, some species appeared to benefit from drought preconditioning, exhibiting greater growth and increased water-use efficiency compared to well-watered plants. This suggests that simple applications of stress treatments could improve plant growth and stress tolerance, but the success of this method is likely very species specific. Restoration practitioners should consider conducting pilot studies with target plant species to better understand if this technique could assist in achieving restoration goals.
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Affiliation(s)
- Justin M Valliere
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, University of California, Los Angeles, Los Angeles, California, 90095, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Jacqueline Zhang
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - M Rasoul Sharifi
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Phillip W Rundel
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, 90095, USA
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Sharifi MR, Khajali F, Hassanpour H, Pour-Reza J, Pirany N. L-arginine supplementation of reduced-protein diets improves pulmonary hypertensive response in broiler chickens reared at high altitude. Br Poult Sci 2015; 56:470-6. [PMID: 26011566 DOI: 10.1080/00071668.2015.1054258] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This study was conducted at high altitude (2100 m above sea level). A total of 208 d-old male broilers (Ross 308) were randomised across 16 floor pens and reared up to 42 d. A normal-protein diet (NPD) was formulated according to the National Research Council. A reduced-protein diet (RPD) was prepared with dietary protein reduced by 30 g/kg relative to that of the NPD. Two additional diets were prepared by adding 2 and 4 g L-arginine (ARG)/kg to the RPD. At the end of trial (42 d), blood sampling was done and carcass characteristics were recorded. ARG supplementation of the RPD at 4 g improved feed:gain in the growing stage and throughout the trial compared with the RPD. The right-to-total ventricular weight ratio was significantly increased in birds fed on RPD compared with those fed on NPD or ARG-supplemented RPD. Feeding RPD caused a significant decrease in plasma concentrations of nitric oxide (NO) and uric acid. Plasma NO level, however, was restored by ARG supplementation of RPD. ARG supplementation of RPD, however, significantly reduced the rate of pulmonary hypertension syndrome mortality compared to the negative control fed on RPD.
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Affiliation(s)
- M R Sharifi
- a Department of Animal Science , Shahrekord University , Shahrekord , Iran
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Nilsen ET, Sharifi MR, Rundel PW, Forseth IN, Ehleringer JR. Water relations of stem succulent trees in north-central Baja California. Oecologia 1990; 82:299-303. [PMID: 28312702 DOI: 10.1007/bf00317474] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/1989] [Accepted: 09/10/1989] [Indexed: 10/26/2022]
Abstract
Water relations of several stem succulent trees were measured in north-central Baja California in comparisons to other growth forms in the same habitat. Our research concentrated on three stem succulent species (Idria collumnaris, Pachycormus discolor and Bursera microphylla) each with a different succulent stem morphology. The stem succulent trees had 1 to 4 kg H2O/m3 of trunk while the other trees and shrubs in the same habitat had 0.6 to 0.8 kg H2O/m3. The diurnal and seasonal variation in leaf water potential was small for the stem succulent species in comparison to deciduous and evergreen species as a consequence of the stem-water, buffering capacity. In addition, the leaf conductance of the stem succulent species was low (60 mmol m-2 s-1) and yet, the leaf conductance decreased through the day similar to adjacent evergreen and deciduous species. The leaves of the stem succulent trees lost turgor at low saturated water deficits (0.06 to 0.14), had comparatively high osmotic potentials, and high values of elastic modulus in comparison to adjacent evergreen and deciduous species. The stem acts as an important buffering mechanism allowing for the maintenance of leaf turgor in these stem succulent trees. The low transpiration rates of the stem succulent trees may be a mechanism to minimize leaf saturated water deficit and extend leaf longevity.
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Affiliation(s)
- E T Nilsen
- Biology Department, Virginia Polytechnic Institute and State University, 24061, Blacksburg, VA, USA
| | - M R Sharifi
- LBES, University of California, 900 Veteran Avenue, 90024, Los Angeles, CA, USA
| | - P W Rundel
- LBES, University of California, 900 Veteran Avenue, 90024, Los Angeles, CA, USA
| | - I N Forseth
- Department of Botany, University of Maryland, 20742, College Park, MD, USA
| | - J R Ehleringer
- Biology Department, University of Utah, 84112, Salt Lake City, UT, USA
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Nilsen ET, Sharifi MR, Rundel PW, Jarrell WM, Virginia RA. Diurnal and Seasonal Water Relations of the Desert Phreatophyte Prosopis Glandulosa (Honey Mesquite) in the Sonoran Desert of California. Ecology 1983. [DOI: 10.2307/1937492] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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