scholarly journals The strategies of water–carbon regulation of plants in a subtropical primary forest on karst soils in China

2018 ◽  
Vol 15 (13) ◽  
pp. 4193-4203 ◽  
Author(s):  
Jing Wang ◽  
Xuefa Wen ◽  
Xinyu Zhang ◽  
Shenggong Li
Keyword(s):  
Plant Species ◽  
Life Forms ◽  
Carbon Gain ◽  
Primary Forest ◽  
Response Curves ◽  
Carboxylase Activity ◽  
Carbon Regulation ◽  
Intrinsic Water Use Efficiency ◽  
Significant Difference ◽  
The Impact

Abstract. Coexisting plant species in a karst ecosystem may use diverse strategies of trade off between carbon gain and water loss to adopt to the low soil nutrient and low water availability conditions. An understanding of the impact of CO2 diffusion and maximum carboxylase activity of Rubisco (Vcmax) on the light-saturated net photosynthesis (A) and intrinsic water use efficiency (iWUE) can provide insight into physiological strategies of the water–carbon regulation of coexisting plant species used in adaptation to karst environments at the leaf scale. We selected 63 dominant species (across 6 life forms) in a subtropical karst primary forest in southwestern China, measured their CO2 response curves, and calculated the corresponding stomatal conductance to CO2 (gs), mesophyll conductance to CO2 (gm), and Vcmax. The results showed that gs and gm varied about 7.6- and 34.5-fold, respectively, and that gs was positively related to gm. The contribution of gm to the leaf CO2 gradient was similar to that of gs. gs ∕ A, gm ∕ A and gt ∕ A was negatively related to Vcmax ∕ A. The relative limitations of gs (ls), gm (lm), and Vcmax (lb) to A for the whole group (combined six life forms) were significantly different from each other (P < 0.05). lm was the largest (0.38 ± 0.12), followed by lb (0.34 ± 0.14), and ls (0.28 ± 0.07). No significant difference was found between ls, lm, and lb for trees and tree/shrubs, while lm was the largest, followed by lb and ls for shrubs, grasses, vines and ferns (P < 0.05). iWUE varied about 3-fold (from 29.52 to 88.92 µmol CO2 mol−1 H2O) across all species, and was significantly correlated with gs, Vcmax, gm ∕ gs, and Vcmax ∕ gs. These results indicated that karst plants maintained relatively high A and low iWUE through the covariation of gs, gm, and Vcmax as an adaptation to a karst environment.

scholarly journals Trade-offs between water loss and carbon gain in a subtropical primary forest on Karst soils in China

2018 ◽  
Author(s):  
Jing Wang ◽  
Xuefa Wen ◽  
Xinyu Zhang ◽  
Shenggong Li
Keyword(s):  
Water Loss ◽  
Southwestern China ◽  
Carbon Gain ◽  
Primary Forest ◽  
Leaf Mass Per Area ◽  
Response Curves ◽  
Carboxylase Activity ◽  
Trade Offs ◽  
Intrinsic Water Use Efficiency ◽  
The Impact

Abstract. Little attention has been given to plants's trade-off between carbon gain and water loss in Karst Critical Zone in southwestern China with low soil nutrient and water availability. An advanced understanding of the impact of CO2 diffusion and maximum carboxylase activity of Rubisco (Vcmax) on the light-saturated net photosynthesis (A) and intrinsic water use efficiency (iWUE) in Karst plants can provide insight into physiological strategies used in adaptation to harsh environments. We selected six plant life forms (63 species) in a subtropical Karst primary forest in southwestern China, and measured CO2 response curves, and calculated corresponding stomatal conductance to CO2 (gs), mesophyll conductance to CO2 (gm), and Vcmax. The results showed that gs varied from 0.05 to 0.38 mol CO2 m−2 s−1, gm varied from 0.02 to 0.69 mol CO2 m−2 s−1, and gm was positively related to gs; foliar A was co-limited by gs, gm, and Vcmax in trees, tree/shrubs, and shrubs with relatively high leaf mass per area (LMA), and mainly constrained by gm in grasses, vines, and ferns with relatively low LMA; and iWUE varied from 29.52 to 88.92 μmol CO2 mol−1 H2O across all species, and was significantly correlated with gs, gm/gs, and Vcmax/gs. These results indicated that Karst plants maintained relatively high A and low iWUE through the co-variation of gs, gm, and Vcmax as adaptation to Karst environment.

scholarly journals The impacts of anthropogenic disturbance on plant species richness in the freshwater lakes of Algonquin Provincial Park

SURG Journal ◽  
2017 ◽  
Vol 9 (1) ◽  
pp. 5-13
Author(s):  
Adrian Helmers ◽  
Alexis Platek ◽  
Melissa Ponte ◽  
Natalie Secen ◽  
Karl Cottenie
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Human Activity ◽  
Anthropogenic Disturbance ◽  
Negative Relationship ◽  
Access Point ◽  
Plant Species Richness ◽  
Significant Difference ◽  
The Impact ◽  
Provincial Park

This study quantified the impact of human activity on aquatic and shoreline plant species richness. We hypothesized that human activity at the shoreline would negatively impact plant species richness and that the extent of the impact would depend on the intensity of human activity. To test this, we sampled 11 lakes in Algonquin Provincial Park, of which five permitted motorboat access, and five permitted canoe access and prohibited motorboat access. The remaining lake, which had no designated access point for boats and was only accessible to researchers, acted as a control. To assess the impact of anthropogenic disturbance at each lake, we measured plant species richness in three 10 m by 2 m plots: a first plot at the access point, assumed to be the site of highest disturbance; a second at the site of intermediate disturbance, 30 m down shore from the access point; and a third at the site of lowest disturbance, 60 m down shore from the access point. We found a significant negative relationship between the level of disturbance and plant species richness, both in the motorboat-accessible and canoe access-only lakes. The control lake exhibited no correlation between disturbance level and plant species richness. However, there was no significant difference between motorboat-accessible and canoe access-only lakes in the relationship between disturbance level and plant species richness. Overall, this study highlights the consequences of anthropogenic disturbance on freshwater aquatic and shoreline plant communities, and provides a framework for future management and rehabilitation strategies.

scholarly journals Flora of Ferruginous Outcrops Under Climate Change: A Study in the Cangas of Carajás (Eastern Amazon)

2021 ◽  
Vol 12 ◽  
Author(s):  
Tereza Cristina Giannini ◽  
André Luis Acosta ◽  
Wilian França Costa ◽  
Leonardo Miranda ◽  
Carlos Eduardo Pinto ◽  
...  
Keyword(s):  
Climate Change ◽  
Plant Species ◽  
Species Distribution Modeling ◽  
National Forest ◽  
Pollination Syndromes ◽  
Species Occurrence ◽  
Significant Difference ◽  
Potential Impact ◽  
Suitable Habitats ◽  
The Impact

Climate change has impacted biodiversity, affecting species and altering their geographical distribution. Besides understanding the impact in the species, it has been advocated that answering if different traits will be differently impacted could allow refined predictions of how climate change will jeopardize biodiversity. Our aim was to evaluate if climate change will potentially impact plant species differently, considering their traits. We evaluated 608 plant species that occur in the naturally open areas of ferruginous outcrops (namely, cangas) in the National Forest of Carajás (Eastern Amazon). Firstly, we estimated the effects of climate change on each species using species distribution modeling, and analyzed this impact in the set containing all species. Secondly, we classified plant species considering the following traits: (i) pollination syndromes (melittophily, phalaenophily, psychophily, cantharophily, entomophily, ornithophily, chiropterophily, anemophily); (ii) habit (tree, shrub, herb, liana, parasite); and (iii) the main habitat of occurrence (open areas and forests). Thirdly, we investigated if the effects of climate change could be significantly more intense considering all the different traits quoted. Our results showed that most plant species will potentially face reduction of suitable habitats under future climate and the scenarios showed that 42% of them may not find suitable areas in the cangas of Carajás. We found no significant difference within each analyzed trait, considering the potential impact of climate change. The most climatically suitable areas (i.e., areas with high probability of species occurrence in the future) are those in the southwest of the study area. These areas can be considered as priority areas for species protection against climate change.

scholarly journals Diversity of medicinal plants at Phia Oac – Phia Den nature reserve, Nguyen Binh district, Cao Bang province

2019 ◽  
Vol 35 (1) ◽  
Author(s):  
Nguyen Ngan Ha
Keyword(s):  
Medicinal Plants ◽  
Essential Oil ◽  
Medicinal Plant ◽  
Plant Species ◽  
Forest Ecosystem ◽  
Nature Reserve ◽  
Life Forms ◽  
Primary Forest ◽  
Different Types ◽  
Total Species

A total number of medicinal plant species found in the surveyed area was 472 species, belonging to 323 genera, 128 families and 5 phyla. There were 110 species (85.94%) of Magnoliophyta, 9 species of Polypodiophyta (7.03%), 6 species of Pinophyta (4.9%), 2 species of Lycopodiophyta (1.56%) and 1 species of Equisetophyta. Nine largest families included 168 species (35.59% of total species) and 103 genera (31.90% of total genera). Medicinal plants in Phia Oac – Phia Den nature reserve were in two main life-forms: Phanerophytes with 267 species (56.57%) and Hemicryptophytes with 78 species (16.52%). Many parts of plants had been used for medicine such as leaves – 71.82%; roots and tubers – 40.25%; sap and essential oil – 40.04%. Medicinal plants were mainly distributed in the grassland and shrubland ecosystem (200 species – 42.37%); in the primary forest ecosystem (182 species – 38.56%).  Medicinal plants had also been used to treat different types of diseases.

scholarly journals Impact of Three Species of Aquatic Plants on Anopheles quadrimaculatus and its Effect on the Efficacy of Boric Acid Sugar Baits

2018 ◽  
Vol 34 (1) ◽  
pp. 50-52
Author(s):  
Kai Blore ◽  
John C. Beier ◽  
Rui-De Xue
Keyword(s):  
Boric Acid ◽  
Plant Species ◽  
Aquatic Plants ◽  
Survival Rates ◽  
Pontederia Cordata ◽  
Anopheles Quadrimaculatus ◽  
Significant Difference ◽  
The Impact ◽  
One Way Anova ◽  
Potential Use

ABSTRACT The purpose of this study was to investigate the sugar-feeding behavior of Anopheles quadrimaculatus by measuring the impact of different aquatic plants on its survival. At the same time, the potential use of boric acid in toxic sugar bait (TSB) applications to the leaves of these plants was also evaluated. Mean survival rates of mosquitoes after 120 h feeding on 3 common aquatic plant species—Thalia geniculata, Pontederia cordata, and Limnobium spongia—were 10.55%, 1.86%, and 6.21%, respectively. No significant difference in mortality between mosquitoes feeding on separate plant species was detected (P = 0.05). The TSB efficacy was evaluated by leaf dip bioassay to compare 24-h mortality of mosquitoes feeding on leaves treated with TSB formulation (1% boric acid, 10% sucrose) and leaves dipped in 10% sucrose. Mortality was significantly higher for TSB-treated leaves for T. geniculata (t = 12.5, df = 8, P &lt; 0.0001) and P. cordata (t = 5.42, df = 8, P = 0.0006) than for L. spongia (t = 1.4003, df = 8, P = 0.199). One-way ANOVA analysis showed no significant difference in efficacy between TSB-treated leaves of the 3 plants.

scholarly journals Examining the Impact of Question Surface Features on Students’ Answers to Constructed-Response Questions on Photosynthesis

2015 ◽  
Vol 14 (2) ◽  
pp. ar19 ◽  
Author(s):  
Michele Weston ◽  
Kevin C. Haudek ◽  
Luanna Prevost ◽  
Mark Urban-Lurain ◽  
John Merrill
Keyword(s):  
Plant Species ◽  
Cell Biology ◽  
Student Responses ◽  
Education Assessment ◽  
Constructed Response ◽  
Surface Features ◽  
Written Responses ◽  
Significant Difference ◽  
Scientific Principles ◽  
The Impact

One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of two question prompts. We asked four versions of the question with different combinations of the two plant species and order of prompts in an introductory cell biology course. We found that there was not a significant difference in the content of student responses to versions of the question stem with different species or order of prompts, using both computerized lexical analysis and expert scoring. We conducted 20 face-to-face interviews with students to further probe the effects of question wording on student responses. During the interviews, we found that students thought that the plant species was neither relevant nor confusing when answering the question. Students identified the prompts as both relevant and confusing. However, this confusion was not specific to a single version.

Epiphytes and hemiepiphytes have slower photosynthetic response to lightflecks than terrestrial plants: evidence from ferns and figs

2009 ◽  
Vol 25 (5) ◽  
pp. 465-472 ◽  
Author(s):  
Qiang Zhang ◽  
Jun-Wen Chen ◽  
Bao-Gui Li ◽  
Kun-Fang Cao
Keyword(s):  
Stomatal Conductance ◽  
Induction Time ◽  
Dark Respiration ◽  
Life Forms ◽  
Carbon Gain ◽  
Terrestrial Plants ◽  
Significant Difference ◽  
Fern Species ◽  
Lower Light ◽  
Photosynthetic Responses

Abstract:Photosynthetic responses of 12 species including six fern species (Neottopteris nidus, Microsorum punctatum, Pseudodrynaria coronans, Asplenium finlaysonianum, Paraleptochilus decurrens and Tectaria fauriei) and seedlings of six fig species (Ficus curtipes, F. gibbosa, F. altissima, F. auriculata, F. oligodon and F. hookeriana) in different life forms to lightfleck were investigated, to test whether epiphytes and hemiepiphytes display a slower response to lightfleck and fast induction loss after a lightfleck compared with their terrestrial counterparts, and whether ferns display a slower response to lightfleck and slower induction loss compared to figs. The measurements of functional traits and physiological parameters were determined in a screenhouse of 4% full sunlight. Epiphytic ferns and hemiepiphytic figs had thicker leaves compared with their terrestrial counterparts. Compared with figs, ferns had thicker fronds, larger stomata with a low density, and lower stomatal conductance and photosynthetic capacity; ferns had lower light compensation point and dark respiration rate, conferring a positive carbon gain under low diffuse light beneath the canopy. The induction time to reach 90% maximum net photosynthetic rate (T90) upon the exposure to a saturated light varied strongly among life forms. Epiphytic ferns had slower T90 than terrestrial ferns (19.9–26.3 vs 5.9–16.3 min, respectively), and hemiepiphytic figs had slower T90 than terrestrial figs (13.1–20.4 vs 5.2–7.8 min, respectively). Compared with figs, ferns showed a slower response to lightfleck. Across ferns and figs, the induction time was negatively correlated with initial stomatal conductance. No significant difference in induction loss was found between two life forms within ferns or figs, whereas ferns had a significantly slower induction loss compared with figs. These results showed that the inherent conservative water use strategy of the epiphytes and hemiepiphytes constrain their lightfleck utilization.

Measuring Impact of Stress in Sandwich Generation Caring for Demented Parents

GeroPsych ◽  
2014 ◽  
Vol 27 (4) ◽  
pp. 171-179 ◽  
Author(s):  
Laurence M. Solberg ◽  
Lauren B. Solberg ◽  
Emily N. Peterson
Keyword(s):  
Factor Analysis ◽  
Exploratory Factor Analysis ◽  
Social Worker ◽  
Resource Availability ◽  
Well Being ◽  
Sandwich Generation ◽  
Item Questionnaire ◽  
Significant Difference ◽  
Adult Caregivers ◽  
The Impact

Stress in caregivers may affect the healthcare recipients receive. We examined the impact of stress experienced by 45 adult caregivers of their elderly demented parents. The participants completed a 32-item questionnaire about the impact of experienced stress. The questionnaire also asked about interventions that might help to reduce the impact of stress. After exploratory factor analysis, we reduced the 32-item questionnaire to 13 items. Results indicated that caregivers experienced stress, anxiety, and sadness. Also, emotional, but not financial or professional, well-being was significantly impacted. There was no significant difference between the impact of caregiver stress on members from the sandwich generation and those from the nonsandwich generation. Meeting with a social worker for resource availability was identified most frequently as a potentially helpful intervention for coping with the impact of stress.

OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1967 ◽  
Vol 56 (4) ◽  
pp. 619-625 ◽  
Author(s):  
Hans Jacob Koed ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Origin ◽  
Response Curves ◽  
Significant Difference ◽  
The Mean ◽  
Different Levels

ABSTRACT Comparison of the dose-response curves for LH of ovine origin (NIH-LH-S8) and of human origin (IRP-HMG-2) using the OAAD test showed a small, though statistically significant difference, the dose-response curve for LH of human origin being a little flatter. Two standard curves for ovine LH obtained with 14 months' interval, were parallel but at different levels of ovarian ascorbic acid. When the mean ascorbic acid depletions were calculated as percentages of the control levels, the two curves for NIH-LH-S8 were identical. The use of standards of human origin in the OAAD test for LH activity of human preparations is recommended.

STUDIES ON SULFATION FACTOR (SF) ACTIVITY OF HUMAN SERUM

1960 ◽  
Vol XXXV (III) ◽  
pp. 381-396 ◽  
Author(s):  
Sven Almqvist
Keyword(s):  
Human Serum ◽  
Normal Serum ◽  
Treatment Level ◽  
Response Curves ◽  
Normal Children ◽  
Significant Difference ◽  
Human Sera ◽  
Normal Humans ◽  
Pre Treatment ◽  
Dose Levels

ABSTRACT The sulfation factor (SF) activity of human sera has been estimated using a modification of the method of Daughaday et al. (1959). Each assay was statistically evaluated. The method had a mean precision of 0.14 and, used as an assay of GH of human serum, a sensitivity in three pituitary dwarfs of 0.1 to 0.6 μg of HGH/ml of serum. SF activity was found at all ages between 1 month and 75 years. There was a significantly lower mean SF activity below the age of half a year. Three cases of pituitary dwarfism had significantly low SF activities of sera. There was no significant difference between the SF activities of sera from untreated pituitary dwarfs and the sera from normal children below half a year of age. Dose-response curves with large volumes of sera from pituitary dwarfs and small volumes of sera from normal humans had the same slopes. Four mg of HGH prepared according to the method of Li & Papkoff (1956) resulted in a normal serum SF activity in each of the three dwarfs. A significant (P < 0.01) linear relationship was found between the concentration of SF activity of sera from these subjects and the logarithm of the dose of HGH given with dose levels of 1, 2 and 4 mg daily for three days. The decline of serum SF activity to the pre-treatment level following HGH in one dwarf suggested a half life not different from that indicated by others for growth hormone.

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