Photosynthetic activity and water use efficiency of Salvia verbenaca L. under elevated CO2 and water‐deficit conditions
- Javaid, Muhammad Mansoor, Florentine, Singarayer, Ashraf, Muhammad, Mahmood, Athar, Sattar, Abdul, Wasaya, Allah, Li, Feng‐Min
- Authors: Javaid, Muhammad Mansoor , Florentine, Singarayer , Ashraf, Muhammad , Mahmood, Athar , Sattar, Abdul , Wasaya, Allah , Li, Feng‐Min
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of agronomy and crop science Vol. 208, no. 4 (2022), p. 536-551
- Full Text:
- Reviewed:
- Description: Investigating the combined effects of elevated CO2 concentration and water‐deficit on weed plants is crucial to gaining a thorough understanding of plant performance and modifying agricultural processes under changing climate conditions. This study examined the effect of elevated CO2 concentration and water‐deficit conditions on leaf gas exchange, water use efficiency, carboxylation efficiency and the photosystem II (PSII) activity of two Salvia verbenaca L., varieties. These varieties were grown under two CO2 concentrations (ambient conditions of 400 ppm and elevated conditions of 700 ppm) and two water regimes (well‐watered [100% field capacity] and water‐deficit conditions [60% field capacity]) in laboratory growth chambers. For 12 days, at 2‐day intervals, (i) leaf gas exchange parameters (photosynthesis rate, stomatal conductance, transpiration rate (E) and intercellular CO2 concentration (Ci)), (ii) water use efficiency (WUE), (iii) intrinsic water use efficiency (IWUE), (iv) instantaneous carboxylation efficiency and (v) PSII activity (fluorescence, quantum yield of PSII, photochemical efficiency of PSII, photochemical quenching and photosynthetic electron transport) were measured. Water‐deficit conditions had negative effects on studied parameters of both varieties, whereas elevated CO2 concentration had positive effects on the gas exchange, water use efficiency and PSII activity of both. Salvia verbenaca varieties grown under water‐deficit conditions from Day 0 to Day 5 showed a partial recovery in most of the parameters when the resumption of the well‐watered regime was reinstituted on Day 6. Salvia verbenaca varieties grown under water‐deficit conditions were re‐watered on day 6 and indicated a partial recovery in all the parameters. A comparison of the two varieties showed that var. vernalis recorded higher values of gas exchange, quantum yield of PSII and photochemical efficiency of PSII than var. verbenaca, but the water use efficiency of var. verbenaca was higher than that of var. vernalis. These differences serve to illustrate the complexity of such studies and suggest that a detailed understanding of the nature of weed infestations is essential if optimum management control is to be practiced. Elevated CO2 concentration mitigated the adverse effects of water‐deficit conditions and thereby enhanced the adaptive mechanism of this weed by improving its water use efficiency. It is thus likely that S. verbenaca has the potential to take advantage of climate change by increasing its relative competitiveness with other plants in drought‐prone areas, suggesting that it could significantly expand its invasive range under such conditions.
- Authors: Javaid, Muhammad Mansoor , Florentine, Singarayer , Ashraf, Muhammad , Mahmood, Athar , Sattar, Abdul , Wasaya, Allah , Li, Feng‐Min
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of agronomy and crop science Vol. 208, no. 4 (2022), p. 536-551
- Full Text:
- Reviewed:
- Description: Investigating the combined effects of elevated CO2 concentration and water‐deficit on weed plants is crucial to gaining a thorough understanding of plant performance and modifying agricultural processes under changing climate conditions. This study examined the effect of elevated CO2 concentration and water‐deficit conditions on leaf gas exchange, water use efficiency, carboxylation efficiency and the photosystem II (PSII) activity of two Salvia verbenaca L., varieties. These varieties were grown under two CO2 concentrations (ambient conditions of 400 ppm and elevated conditions of 700 ppm) and two water regimes (well‐watered [100% field capacity] and water‐deficit conditions [60% field capacity]) in laboratory growth chambers. For 12 days, at 2‐day intervals, (i) leaf gas exchange parameters (photosynthesis rate, stomatal conductance, transpiration rate (E) and intercellular CO2 concentration (Ci)), (ii) water use efficiency (WUE), (iii) intrinsic water use efficiency (IWUE), (iv) instantaneous carboxylation efficiency and (v) PSII activity (fluorescence, quantum yield of PSII, photochemical efficiency of PSII, photochemical quenching and photosynthetic electron transport) were measured. Water‐deficit conditions had negative effects on studied parameters of both varieties, whereas elevated CO2 concentration had positive effects on the gas exchange, water use efficiency and PSII activity of both. Salvia verbenaca varieties grown under water‐deficit conditions from Day 0 to Day 5 showed a partial recovery in most of the parameters when the resumption of the well‐watered regime was reinstituted on Day 6. Salvia verbenaca varieties grown under water‐deficit conditions were re‐watered on day 6 and indicated a partial recovery in all the parameters. A comparison of the two varieties showed that var. vernalis recorded higher values of gas exchange, quantum yield of PSII and photochemical efficiency of PSII than var. verbenaca, but the water use efficiency of var. verbenaca was higher than that of var. vernalis. These differences serve to illustrate the complexity of such studies and suggest that a detailed understanding of the nature of weed infestations is essential if optimum management control is to be practiced. Elevated CO2 concentration mitigated the adverse effects of water‐deficit conditions and thereby enhanced the adaptive mechanism of this weed by improving its water use efficiency. It is thus likely that S. verbenaca has the potential to take advantage of climate change by increasing its relative competitiveness with other plants in drought‐prone areas, suggesting that it could significantly expand its invasive range under such conditions.
Photosynthetic responses of Invasive Acacia mangium and co-existing native heath forest species to elevated temperature and CO2 concentrations
- Ibrahim, Mohamad, Sukri, Rahayu, Tennakoon, Kushan, Le, Quang-Vuong, Metali, Faizah
- Authors: Ibrahim, Mohamad , Sukri, Rahayu , Tennakoon, Kushan , Le, Quang-Vuong , Metali, Faizah
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Sustainable Forestry Vol. 40, no. 6 (2021), p. 573-593
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- Reviewed:
- Description: The impacts of climate change, in particular via elevated temperature and atmospheric CO2 concentrations, cause differential photosynthetic responses between native and invasive alien plants, often resulting in varying magnitudes of plant growth and productivity. This study investigated variations in photosynthetic responses of an invasive alien Acacia species and two successional groups of tropical heath forest species: early secondary (Buchanania arborescens and Dillenia suffruticosa) and secondary (Calophyllum inophyllum and Ploiarium alternifolium) groups at elevated temperature (25 to 30°C) and CO2 levels (400 to 700 ppm). Invasive A.mangium appears better adapted to higher temperature and CO2. High temperature improved CO2 assimilation of A.mangium compared to heath species, which was attributed to increased transpiration rate and stomatal conductance but decreased water-use efficiency. Photosynthetic responses showed no differences in early secondary species at elevated temperature and CO2 but invasive A.mangium and P.alternifolium were stimulated by elevated CO2. The greater maximum net photosynthesis of A.mangium coincided with lower light compensation point and electron transport rate for RuBP regeneration, to a certain extent. Findings provide insights into possible underlying ecophysiological mechanisms contributing to the invasion success of Acacias in degraded tropical heath forests in response to future climate change. © 2020 Taylor & Francis.
- Authors: Ibrahim, Mohamad , Sukri, Rahayu , Tennakoon, Kushan , Le, Quang-Vuong , Metali, Faizah
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Sustainable Forestry Vol. 40, no. 6 (2021), p. 573-593
- Full Text:
- Reviewed:
- Description: The impacts of climate change, in particular via elevated temperature and atmospheric CO2 concentrations, cause differential photosynthetic responses between native and invasive alien plants, often resulting in varying magnitudes of plant growth and productivity. This study investigated variations in photosynthetic responses of an invasive alien Acacia species and two successional groups of tropical heath forest species: early secondary (Buchanania arborescens and Dillenia suffruticosa) and secondary (Calophyllum inophyllum and Ploiarium alternifolium) groups at elevated temperature (25 to 30°C) and CO2 levels (400 to 700 ppm). Invasive A.mangium appears better adapted to higher temperature and CO2. High temperature improved CO2 assimilation of A.mangium compared to heath species, which was attributed to increased transpiration rate and stomatal conductance but decreased water-use efficiency. Photosynthetic responses showed no differences in early secondary species at elevated temperature and CO2 but invasive A.mangium and P.alternifolium were stimulated by elevated CO2. The greater maximum net photosynthesis of A.mangium coincided with lower light compensation point and electron transport rate for RuBP regeneration, to a certain extent. Findings provide insights into possible underlying ecophysiological mechanisms contributing to the invasion success of Acacias in degraded tropical heath forests in response to future climate change. © 2020 Taylor & Francis.
Atmospheric CO₂ Concentration and Other Limiting Factors in the Growth of C₃ and C₄ Plants
- Boretti, Albert, Florentine, Singarayer
- Authors: Boretti, Albert , Florentine, Singarayer
- Date: 2019
- Type: Text , Journal article
- Relation: Plants Vol. 8, no. 4 (2019), p. 1-11
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- Reviewed:
- Description: It has been widely observed that recent increases in atmospheric CO2 concentrations have had, so far, a positive effect on the growth of plants. This is not surprising since CO2 is an important nutrient for plant matter, being directly involved in photosynthesis. However, it is also known that the conditions which have accompanied this increase in atmospheric CO2 concentration have also had significant effects on other environmental factors. It is possible that these other effects may emerge as limiting factors which could act to prevent plant growth. This may involve complex interactions between prevailing sunlight and water conditions, variable temperatures, the availability of essential nutrients and the type of synthetic pathway for the plant species. The issue of concern to this investigation is if we should be worried about a possible shift in the C3-C4 paradigm driven by changes in the atmospheric CO2 concentration, or if some other factor, such as water scarcity, is much more relevant within a 30-year time frame. If an opinion is needed on what will have the worst effect on the survival of the planet between the scarcity of water or the reduced efficiency of C3 plants to sequester CO2, the issue of water is the more incisive.
- Authors: Boretti, Albert , Florentine, Singarayer
- Date: 2019
- Type: Text , Journal article
- Relation: Plants Vol. 8, no. 4 (2019), p. 1-11
- Full Text:
- Reviewed:
- Description: It has been widely observed that recent increases in atmospheric CO2 concentrations have had, so far, a positive effect on the growth of plants. This is not surprising since CO2 is an important nutrient for plant matter, being directly involved in photosynthesis. However, it is also known that the conditions which have accompanied this increase in atmospheric CO2 concentration have also had significant effects on other environmental factors. It is possible that these other effects may emerge as limiting factors which could act to prevent plant growth. This may involve complex interactions between prevailing sunlight and water conditions, variable temperatures, the availability of essential nutrients and the type of synthetic pathway for the plant species. The issue of concern to this investigation is if we should be worried about a possible shift in the C3-C4 paradigm driven by changes in the atmospheric CO2 concentration, or if some other factor, such as water scarcity, is much more relevant within a 30-year time frame. If an opinion is needed on what will have the worst effect on the survival of the planet between the scarcity of water or the reduced efficiency of C3 plants to sequester CO2, the issue of water is the more incisive.
Influence of soil moisture regimes on growth, photosynthetic capacity, leaf biochemistry and reproductive capabilities of the invasive agronomic weed; Lactuca serriola
- Chadha, Aakansha, Florentine, Singarayer, Chauhan, Bhagirath, Long, Benjamin, Jayasundera, Mithila
- Authors: Chadha, Aakansha , Florentine, Singarayer , Chauhan, Bhagirath , Long, Benjamin , Jayasundera, Mithila
- Date: 2019
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 14, no. 6 (2019), p. 1-17
- Full Text:
- Reviewed:
- Description: Global temperatures are predicted to increase by 1.5–5.9C during this century, and this change is likely to impact average rainfall, with predictions that water deficit will perhaps be the most severe threat to sustainable agriculture. In this respect, invasive weeds, which have traits better adapted to drought stress than crops, add to concerns regarding crop sustainability. Lactuca serriola, an aggressive agronomic weed is thought to be a successful weed because of its ability to maintain high water use efficiency under drought conditions. In this study, experiments were conducted to examine the influence of different soil moisture regimes (100%, 75%, 50% and 25% water holding capacity (WHC)) on growth, photosynthetic capacity, leaf biochemistry and reproduction of this species. Soil moisture significantly affected plant’s height, stem diameter, number of leaves and biomass. The highest plant height (115.14 cm ± 11.64), shoot diameter (9.4 mm ± 0.18), leaf area (1206.5 mm2 ± 73.29), plant fresh weight (83.1 ± 3.98) and dry weight (22.38 ± 1.24) were recorded at 75% soil moisture content. A fundamental adaptation to drought was observed as plants in the 25% WHC treatment had the highest root: shoot ratio. Soluble sugars and total phenolic content were highest in the 25% WHC treatment and significantly different to 100% WHC which was a response to soil moisture stress to ameliorate the damaging effects of reactive oxygen species produced under stress conditions. Results also indicate that L. serriola can survive and produce seeds under water stress as more than 6000 seeds were produced per plant in all WHC treatments. In this study, there was no significant difference in the seed weight, number of seeds produced and their germination ability. This can have a huge impact on agricultural systems as the species can survive both under low and high soil moisture conditions. We therefore suggest that the demonstrated ability of L. serriola to complete its life cycle and produce biomass and seeds under water stressed conditions leads to the introduction of strategies that minimize weed survival while maximizing irrigation efficiency for the crop. A clear understanding of the ecological and biological characteristics of this weed will help land managers take appropriate control measures to mitigate the effect of this species on economic crop productivity.
- Authors: Chadha, Aakansha , Florentine, Singarayer , Chauhan, Bhagirath , Long, Benjamin , Jayasundera, Mithila
- Date: 2019
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 14, no. 6 (2019), p. 1-17
- Full Text:
- Reviewed:
- Description: Global temperatures are predicted to increase by 1.5–5.9C during this century, and this change is likely to impact average rainfall, with predictions that water deficit will perhaps be the most severe threat to sustainable agriculture. In this respect, invasive weeds, which have traits better adapted to drought stress than crops, add to concerns regarding crop sustainability. Lactuca serriola, an aggressive agronomic weed is thought to be a successful weed because of its ability to maintain high water use efficiency under drought conditions. In this study, experiments were conducted to examine the influence of different soil moisture regimes (100%, 75%, 50% and 25% water holding capacity (WHC)) on growth, photosynthetic capacity, leaf biochemistry and reproduction of this species. Soil moisture significantly affected plant’s height, stem diameter, number of leaves and biomass. The highest plant height (115.14 cm ± 11.64), shoot diameter (9.4 mm ± 0.18), leaf area (1206.5 mm2 ± 73.29), plant fresh weight (83.1 ± 3.98) and dry weight (22.38 ± 1.24) were recorded at 75% soil moisture content. A fundamental adaptation to drought was observed as plants in the 25% WHC treatment had the highest root: shoot ratio. Soluble sugars and total phenolic content were highest in the 25% WHC treatment and significantly different to 100% WHC which was a response to soil moisture stress to ameliorate the damaging effects of reactive oxygen species produced under stress conditions. Results also indicate that L. serriola can survive and produce seeds under water stress as more than 6000 seeds were produced per plant in all WHC treatments. In this study, there was no significant difference in the seed weight, number of seeds produced and their germination ability. This can have a huge impact on agricultural systems as the species can survive both under low and high soil moisture conditions. We therefore suggest that the demonstrated ability of L. serriola to complete its life cycle and produce biomass and seeds under water stressed conditions leads to the introduction of strategies that minimize weed survival while maximizing irrigation efficiency for the crop. A clear understanding of the ecological and biological characteristics of this weed will help land managers take appropriate control measures to mitigate the effect of this species on economic crop productivity.
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