Achievements, developments and future challenges in the field of bioherbicides for weed control : a global review
- Roberts, Jason, Florentine, Singarayer, Fernando, Wannakuwattewaduge, Tennakoon, Kushan
- Authors: Roberts, Jason , Florentine, Singarayer , Fernando, Wannakuwattewaduge , Tennakoon, Kushan
- Date: 2022
- Type: Text , Journal article
- Relation: Plants Vol. 11, no. 17 (2022), p.
- Full Text:
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- Description: The intrusion of weeds into fertile areas has resulted in significant global economic and environmental impacts on agricultural production systems and native ecosystems, hence without ongoing and repeated management actions, the maintenance or restoration of these systems will become increasingly challenging. The establishment of herbicide resistance in many species and unwanted pollution caused by synthetic herbicides has ushered in the need for alternative, eco-friendly sustainable management strategies, such as the use of bioherbicides. Of the array of bioherbicides currently available, the most successful products appear to be sourced from fungi (mycoherbicides), with at least 16 products being developed for commercial use globally. Over the last few decades, bioherbicides sourced from bacteria and plant extracts (such as allelochemicals and essential oils), together with viruses, have also shown marked success in controlling various weeds. Despite this encouraging trend, ongoing research is still required for these compounds to be economically viable and successful in the long term. It is apparent that more focused research is required for (i) the improvement of the commercialisation processes, including the cost-effectiveness and scale of production of these materials; (ii) the discovery of new production sources, such as bacteria, fungi, plants or viruses and (iii) the understanding of the environmental influence on the efficacy of these compounds, such as atmospheric CO2, humidity, soil water stress, temperature and UV radiation. © 2022 by the authors.
- Authors: Roberts, Jason , Florentine, Singarayer , Fernando, Wannakuwattewaduge , Tennakoon, Kushan
- Date: 2022
- Type: Text , Journal article
- Relation: Plants Vol. 11, no. 17 (2022), p.
- Full Text:
- Reviewed:
- Description: The intrusion of weeds into fertile areas has resulted in significant global economic and environmental impacts on agricultural production systems and native ecosystems, hence without ongoing and repeated management actions, the maintenance or restoration of these systems will become increasingly challenging. The establishment of herbicide resistance in many species and unwanted pollution caused by synthetic herbicides has ushered in the need for alternative, eco-friendly sustainable management strategies, such as the use of bioherbicides. Of the array of bioherbicides currently available, the most successful products appear to be sourced from fungi (mycoherbicides), with at least 16 products being developed for commercial use globally. Over the last few decades, bioherbicides sourced from bacteria and plant extracts (such as allelochemicals and essential oils), together with viruses, have also shown marked success in controlling various weeds. Despite this encouraging trend, ongoing research is still required for these compounds to be economically viable and successful in the long term. It is apparent that more focused research is required for (i) the improvement of the commercialisation processes, including the cost-effectiveness and scale of production of these materials; (ii) the discovery of new production sources, such as bacteria, fungi, plants or viruses and (iii) the understanding of the environmental influence on the efficacy of these compounds, such as atmospheric CO2, humidity, soil water stress, temperature and UV radiation. © 2022 by the authors.
- Ibrahim, Mohamad, Sukri, Rahayu, Tennakoon, Kushan, Rosli, Nurul, Metali, Faizah
- Authors: Ibrahim, Mohamad , Sukri, Rahayu , Tennakoon, Kushan , Rosli, Nurul , Metali, Faizah
- Date: 2023
- Type: Text , Journal article
- Relation: Journal of Soil Science and Plant Nutrition Vol. 23, no. 3 (2023), p. 3393-3406
- Full Text: false
- Reviewed:
- Description: This study investigates the impacts of Acacia invasion on Bornean heath forest (HF) soils. Soil profiles and water properties at one soil depth (< 1 m) and physicochemical properties with Soil Fertility Index(SFI) and Soil Evaluation Factor (SEF) from the topsoil or three soil depths of Acacia-invaded and non-invaded HF were assessed. Acacia invasion modified soil profiles by producing thicker horizons O and B but waning horizon E. Thick leaf litter layer in invaded HF was associated with a significant decrease in soil bulk density, moisture, organic matter (OM), total organic carbon, water volume, and NH4+ but a significant increase in soil temperature, and soil water pH, NO3
Effects of Acacia invasion on leaf litter nutrient and soil properties of coastal Kerangas forests in Brunei Darussalam
- Yusoff, Aiman, Tennakoon, Kushan, Jaafar, Salwana, Zaman, Dk, Sukri, Rahayu
- Authors: Yusoff, Aiman , Tennakoon, Kushan , Jaafar, Salwana , Zaman, Dk , Sukri, Rahayu
- Date: 2019
- Type: Text , Journal article
- Relation: Scientia Bruneiana Vol. 18, no. 1 (2019), p. 1-10
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- Description: Exotic Acacia were introduced to Brunei Darussalam in the 1990s for plantation forestry and land rehabilitation but are now regarded as invasive. We assessed the effects of Acacia on litter nutrient composition and soil physicochemical properties of Brunei’s coastal Kerangas (heath) forests. Soil and litter samples were collected from ten 20 x 20 m plots in Acacia-invaded Kerangas forests (IKF) and ten uninvaded (UKF) plots. Soil samples were analyzed for pH, gravimetric water content and nutrient concentrations whereas litter samples were analyzed for total nutrients only. We recorded significantly higher concentrations of litter total N and P in the IKF than the UKF plots. In contrast, no significant differences were detected in soil properties, except for topsoil available P and subsoil exchangeable Ca which were both lower in the IKF plots. A significant positive correlation was detected between litter N and topsoil N in the IKF plots. We suggest that the fairly recent timescale of Acacia invasion (< 25 years) of the IKF sites resulted in the lack of significant increase of soil nutrients. In conclusion, Acacia invasion into Brunei’s forests can potentially alter both leaf litter and soil physicochemical properties of Kerangas forests, in particular affecting nutrient availability. This alteration of ecosystem may further enhance the invasion success of Acacia, making restoration attempts more challenging.
- Authors: Yusoff, Aiman , Tennakoon, Kushan , Jaafar, Salwana , Zaman, Dk , Sukri, Rahayu
- Date: 2019
- Type: Text , Journal article
- Relation: Scientia Bruneiana Vol. 18, no. 1 (2019), p. 1-10
- Full Text:
- Reviewed:
- Description: Exotic Acacia were introduced to Brunei Darussalam in the 1990s for plantation forestry and land rehabilitation but are now regarded as invasive. We assessed the effects of Acacia on litter nutrient composition and soil physicochemical properties of Brunei’s coastal Kerangas (heath) forests. Soil and litter samples were collected from ten 20 x 20 m plots in Acacia-invaded Kerangas forests (IKF) and ten uninvaded (UKF) plots. Soil samples were analyzed for pH, gravimetric water content and nutrient concentrations whereas litter samples were analyzed for total nutrients only. We recorded significantly higher concentrations of litter total N and P in the IKF than the UKF plots. In contrast, no significant differences were detected in soil properties, except for topsoil available P and subsoil exchangeable Ca which were both lower in the IKF plots. A significant positive correlation was detected between litter N and topsoil N in the IKF plots. We suggest that the fairly recent timescale of Acacia invasion (< 25 years) of the IKF sites resulted in the lack of significant increase of soil nutrients. In conclusion, Acacia invasion into Brunei’s forests can potentially alter both leaf litter and soil physicochemical properties of Kerangas forests, in particular affecting nutrient availability. This alteration of ecosystem may further enhance the invasion success of Acacia, making restoration attempts more challenging.
Germination strategy of chenopodium acuminatum Willd. under Fluctuating Salinity Habitats
- Tian, Yu, Li, Yang, Zhang, Hongxiang, Tennakoon, Kushan, Sun, Zewei
- Authors: Tian, Yu , Li, Yang , Zhang, Hongxiang , Tennakoon, Kushan , Sun, Zewei
- Date: 2023
- Type: Text , Journal article
- Relation: Agronomy Vol. 13, no. 11 (2023), p.
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- Description: Germination events of plants often occur after rainfall in saline environments where the soil salinity is diluted, viz recovery germination. Previous germination studies have rarely considered the duration of exposure to salt stress, and none of them have investigated recovery germination under low-salt concentration, other than in distilled water. The main objective of this study was to investigate the effects of salinity, exposure duration and low-salt recovery solutions on seed germination of the weed Chenopodium acuminatum to get a clear insight about the germination strategy exhibited by this species in a saline habitat. Seeds were initially exposed to 0–400 mM NaCl for 10, 20 and 30 d. The subsequent recovery experiment was conducted differently. For those initially treated with 100 and 200 mM NaCl, the recovery solution was distilled water, while for those initially treated with 300 and 400 mM NaCl, the recovery solution was distilled water, at 50 and 100 mM NaCl. Results showed that the recovery germination percentage and rate significantly decreased when the exposure duration extended. Seeds could subsequently recover to germinate at high percentages at recovery salt solution concentrations for a short duration, but the recovery percentages and rates in high salinity, combined with high exposure duration and relatively high recovery salt concentrations, were remarkably lower. More than 30% of the ungerminated seeds were viable after the recovery experiment. We suggest that Ch. acuminatum exhibits a ‘cautious’ strategy of germination to avoid injury from long-term salt stress and ensure survival for the subsequent continuation of its population under unfavorable saline conditions. © 2023 by the authors.
- Authors: Tian, Yu , Li, Yang , Zhang, Hongxiang , Tennakoon, Kushan , Sun, Zewei
- Date: 2023
- Type: Text , Journal article
- Relation: Agronomy Vol. 13, no. 11 (2023), p.
- Full Text:
- Reviewed:
- Description: Germination events of plants often occur after rainfall in saline environments where the soil salinity is diluted, viz recovery germination. Previous germination studies have rarely considered the duration of exposure to salt stress, and none of them have investigated recovery germination under low-salt concentration, other than in distilled water. The main objective of this study was to investigate the effects of salinity, exposure duration and low-salt recovery solutions on seed germination of the weed Chenopodium acuminatum to get a clear insight about the germination strategy exhibited by this species in a saline habitat. Seeds were initially exposed to 0–400 mM NaCl for 10, 20 and 30 d. The subsequent recovery experiment was conducted differently. For those initially treated with 100 and 200 mM NaCl, the recovery solution was distilled water, while for those initially treated with 300 and 400 mM NaCl, the recovery solution was distilled water, at 50 and 100 mM NaCl. Results showed that the recovery germination percentage and rate significantly decreased when the exposure duration extended. Seeds could subsequently recover to germinate at high percentages at recovery salt solution concentrations for a short duration, but the recovery percentages and rates in high salinity, combined with high exposure duration and relatively high recovery salt concentrations, were remarkably lower. More than 30% of the ungerminated seeds were viable after the recovery experiment. We suggest that Ch. acuminatum exhibits a ‘cautious’ strategy of germination to avoid injury from long-term salt stress and ensure survival for the subsequent continuation of its population under unfavorable saline conditions. © 2023 by the authors.
Impacts of invasive Acacias on ion deposition in a coastal Bornean tropical heath forest
- Ibrahim, Mohamad, Metali, Faizah, Tennakoon, Kushan, Sukri, Rahayu
- Authors: Ibrahim, Mohamad , Metali, Faizah , Tennakoon, Kushan , Sukri, Rahayu
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of Forest Research Vol. 27, no. 1 (2022), p. 20-27
- Full Text: false
- Reviewed:
- Description: The uncontrolled invasive spread of exotic Acacias is a growing concern for many tropical ecosystems, particularly due to their negative impact upon nutrient cycling. Studies investigating the effects of Acacia invasion on nutrient cycling have focused on litterfall and litter decomposition, although its impact on ion deposition in tropical ecosystems is less understood. We quantified and compared the rates of ion deposition (Ca2+, Mg2+, NH4+, NO3−) between Acacia-invaded and non-invaded tropical heath (Kerangas) forest sites in Brunei Darussalam, Southeast Asia. Ion exchange resin (IER) sampler, IER ring and IER bags were used to determine ion depositions via throughfall, in soils and in stream water respectively. Throughfall in Acacia-invaded heath forest sites recorded significantly higher NH4+ and Ca2+ depositions but lower Mg2+ than non-invaded, intact sites. For ion deposition in soil, all depths recorded significantly higher Ca2+ (except for 0 cm depth), Mg2+ and NH4+ depositions, but significantly lower NO3− depositions, in Acacia-invaded sites. Ion deposition in stream water showed significant monthly variations, with Acacia-invaded sites recording significantly higher Mg2+ depositions in June, August and September 2015 but lower NH4+ depositions in June, July and September, lower NO3− and Ca2+ depositions in June and September than non-invaded heath forest sites. Overall, these findings demonstrate that ion deposition via throughfall, in soil and in stream water were all affected by Acacia invasion, thus confirming the influence of alien invasive Acacias on nutrient cycling of tropical heath forests. © 2021 The Japanese Forest Society.
Medicinal value of three agricultural weed species of the asteraceae family : a review
- Jayasundera, Mithila, Florentine, Singarayer, Tennakoon, Kushan, Chauhan, Bhagirath
- Authors: Jayasundera, Mithila , Florentine, Singarayer , Tennakoon, Kushan , Chauhan, Bhagirath
- Date: 2021
- Type: Text , Journal article , Review
- Relation: Pharmacognosy Journal Vol. 13, no. 1 (2021), p. 264-277
- Full Text:
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- Description: Ageratum conyzoides L., Tridax procumbens L. and Bidens pilosa L. are well known plant species of the Asteraceae family that are considered weeds in intensive agriculture. These weeds are traditionally known to have medicinal properties and have been used for therapeutic treatments. However, it is only the lack of proper knowledge, awareness and screening that have limited their use in pharmaceutical sectors. This review attempts to consolidate the traditional, phytochemical and pharmacological studies that have been carried out on Ageratum conyzoides L., Tridax procumbens L. and Bidens pilosa L., which we note are widely spread throughout the world. This study was conducted through a coherent search on Ageratum conyzoides L., Tridax procumbens L. and Bidens pilosa L. with respect to traditional uses, phytochemical and pharmacological studies that have been performed on these three agricultural weeds all over the world. An exploration of reported descriptions of the potential medical importance of three agricultural weed species (A. conyzoides, T. procumbens and B. pilosa) has been presented. The present review would encourage further clinical investigations into these three plants and their extracts to more closely define the range of uses of these herbs for clinical applications. This, in turn, would give a clear understanding whether these weed species might be targeted to be conserved in a sustainable manner rather than eradicated. © 2021 Phcogj.Com. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
- Authors: Jayasundera, Mithila , Florentine, Singarayer , Tennakoon, Kushan , Chauhan, Bhagirath
- Date: 2021
- Type: Text , Journal article , Review
- Relation: Pharmacognosy Journal Vol. 13, no. 1 (2021), p. 264-277
- Full Text:
- Reviewed:
- Description: Ageratum conyzoides L., Tridax procumbens L. and Bidens pilosa L. are well known plant species of the Asteraceae family that are considered weeds in intensive agriculture. These weeds are traditionally known to have medicinal properties and have been used for therapeutic treatments. However, it is only the lack of proper knowledge, awareness and screening that have limited their use in pharmaceutical sectors. This review attempts to consolidate the traditional, phytochemical and pharmacological studies that have been carried out on Ageratum conyzoides L., Tridax procumbens L. and Bidens pilosa L., which we note are widely spread throughout the world. This study was conducted through a coherent search on Ageratum conyzoides L., Tridax procumbens L. and Bidens pilosa L. with respect to traditional uses, phytochemical and pharmacological studies that have been performed on these three agricultural weeds all over the world. An exploration of reported descriptions of the potential medical importance of three agricultural weed species (A. conyzoides, T. procumbens and B. pilosa) has been presented. The present review would encourage further clinical investigations into these three plants and their extracts to more closely define the range of uses of these herbs for clinical applications. This, in turn, would give a clear understanding whether these weed species might be targeted to be conserved in a sustainable manner rather than eradicated. © 2021 Phcogj.Com. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
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
- 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.
- 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.
The Angiosperm Stem Hemiparasitic Genus Cassytha (Lauraceae) and its host interactions : a review
- Zhang, Hongxiang, Florentine, Singarayer, Tennakoon, Kushan
- Authors: Zhang, Hongxiang , Florentine, Singarayer , Tennakoon, Kushan
- Date: 2022
- Type: Text , Journal article , Review
- Relation: Frontiers in Plant Science Vol. 13, no. (2022), p.
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- Description: Cassytha, also known as laurel dodder or love vine, is a stem hemiparasite of the Lauraceae family. It has long been used for medicinal purposes in many countries and has increasingly influenced agricultural and natural ecosystems by its effects on a wide range of host species. Previous studies have focused on the taxonomy and evolutionary position of different Cassytha, with the pan-tropical species Cassytha filiformis being the most widely studied. However, Cassytha–host interactions have never been reviewed, which is an essential issue related to the understanding of mechanisms underlying plant hemiparasitic and the assessment of benefits and damage caused by aerial parasitic plants. This review explores the parasitic habits, worldwide distribution, and host range of Cassytha, and examines its impacts on the biology of host plants and the overall influence of environmental changes on Cassytha–host associations. We also comment on areas of future research directions that require to better understanding Cassytha–host interactions. It appeared that some traits, such as flowering phenology, facilitated Cassytha’s widespread distribution and successful parasitism and that Cassytha preferred woody species rather than herbaceous species as a host, and preferred species from certain families as hosts, such as Fabaceae and Myrtaceae. Cassytha often decreased biomass and impacted the physiology of host species and global environmental changes seemed to intensify the negative impacts of Cassytha on their hosts. Cassytha was not only a noxious weed, but can also function as a biocontrol agent to mitigate alien plant invasion. Copyright © 2022 Zhang, Florentine and Tennakoon.
- Authors: Zhang, Hongxiang , Florentine, Singarayer , Tennakoon, Kushan
- Date: 2022
- Type: Text , Journal article , Review
- Relation: Frontiers in Plant Science Vol. 13, no. (2022), p.
- Full Text:
- Reviewed:
- Description: Cassytha, also known as laurel dodder or love vine, is a stem hemiparasite of the Lauraceae family. It has long been used for medicinal purposes in many countries and has increasingly influenced agricultural and natural ecosystems by its effects on a wide range of host species. Previous studies have focused on the taxonomy and evolutionary position of different Cassytha, with the pan-tropical species Cassytha filiformis being the most widely studied. However, Cassytha–host interactions have never been reviewed, which is an essential issue related to the understanding of mechanisms underlying plant hemiparasitic and the assessment of benefits and damage caused by aerial parasitic plants. This review explores the parasitic habits, worldwide distribution, and host range of Cassytha, and examines its impacts on the biology of host plants and the overall influence of environmental changes on Cassytha–host associations. We also comment on areas of future research directions that require to better understanding Cassytha–host interactions. It appeared that some traits, such as flowering phenology, facilitated Cassytha’s widespread distribution and successful parasitism and that Cassytha preferred woody species rather than herbaceous species as a host, and preferred species from certain families as hosts, such as Fabaceae and Myrtaceae. Cassytha often decreased biomass and impacted the physiology of host species and global environmental changes seemed to intensify the negative impacts of Cassytha on their hosts. Cassytha was not only a noxious weed, but can also function as a biocontrol agent to mitigate alien plant invasion. Copyright © 2022 Zhang, Florentine and Tennakoon.
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