Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminate... more Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminated with metals from mining activities, the danger of human intoxication exists. An experiment with plants exposed to cadmium (Cd) was performed to investigate the response of M. plumbea to this heavy metal, its uptake and translocation to plant organs and reaction of root tissues. Plants grown from seeds were cultivated in controlled conditions. Hydroponic cultivation is not suitable for this species as roots do not tolerate aquatic conditions, and additional stress by Cd treatment results in total root growth inhibition and death. After cultivation in perlite the plants exposed to 1 and 5 mg Cd L(-1) in half-strength Hoagland's solution were compared with control plants. Growth parameters were evaluated, Cd content was determined by inductively coupled plasma mass spectroscopy (ICP-MS) and root structure was investigated using various staining procedures, including the fluorescent st...
Javier Abadia Chedly Abdelly Patrick Achard Jeffrey W. Adelberg Randy Allen Nick Amrhein Klaus Ap... more Javier Abadia Chedly Abdelly Patrick Achard Jeffrey W. Adelberg Randy Allen Nick Amrhein Klaus Appenroth Rich Arteca Kozi Asada Folkard Asch Muhammed Ashraf Frantisek Baluska Graham Barry John Beeching Maria Patricia Benavides Ajaya Biswal Miguel Angel Blazquez Eduardo Blumwald M. Bolker Miguel Botella Helen Bramley Adina Breiman Ray Bressan Q. Cai James J. Campanella Jorge Canhoto A. Elizabete Carmo-Silva Paula Casati Fabricio Cassan Ming-Tsair Chan Ming-Shun Chen Lailiang Cheng Hyun-Taeg Cho Won-Gyu Choi Jyh-Ching Chou Morris Cline Steve Clouse Jerry D. Cohen Francisco Javier Corpas Grant Cramer Teresa Cutright Christopher Davies Peter Davies Luigi De Bellis Geert-Jan De Klerk Laura de la Canal Darleen A. DeMason Michael Deyholos H. S. Dhaliwal Nihal Dharmasiri Ian C. Dodd Frances DuPont David Ehret R.J. Neil Emery Eric van der Graaff Carolina Escobar Louise Ferguson Helena Fernandez Raffaella Filippini Judith Fliegmann Ryo Funada Susheng Gan Jose L. Garcia-Martinez J. Garcia-Mina Gary Gardner Lauren Garner Hernâni Gerós Anthony Glass Martin Goffinet Yolanda Gogorcena Albensio Gomes Silveira Dennis Greer Patrick Gulick Edward Gwozdz Mohammad-Reza Hajirezaeir David Hannapel Karl H. Hasenstein Bettina Hause Dirk B. Hays Xiaodong Huang Zhonglian Huang Yang Ju Im Tari Irma Takahiro Ishikawa Abdelbagi Ismail Thomas Jack Mike Jackson Mukesh Jain Cheruth Abdul Jaleel Tibor Janda Christer Jansson Dominique Job Michelle Jones Raymond Jongschaap Miroslav Kaminek Ching-Huei Kao
... WA Stirk* & J. Van Staden Natal University Research Unit for Plant Growth and Development... more ... WA Stirk* & J. Van Staden Natal University Research Unit for Plant Growth and Development, Department of Botany, University of Natal Pietermaritzburg, Private Bag X01, Scottsville ... Indole-butyric acid (IBA) over a concentration range of 10-7-10-4 M was used as the standard. ...
The use of plant growth regulators is well established and they are used in many fields of plant ... more The use of plant growth regulators is well established and they are used in many fields of plant science for enhancing growth. Brassica juncea plants were treated with 2.5, 5.0 and 7.5 microM auxin indole-3-butyric acid (IBA), which promotes rooting. The IBA-treated plants were also sprayed with 100 microM gibberellic acid (GA3) and kinetin (Kin) to increase leaf-foliage. Gold (I) chloride (AuCl) was added to the growth medium of plants to achieve required gold concentration. The solubilizing agent ammonium thiocyanate (1 g kg(-1)) (commonly used in mining industries to solubilize gold) was added to the nutrient solution after six weeks of growth and, two weeks later, plants were harvested. Plant growth regulators improved shoot and root dry biomass of B. juncea plants. Inductively Coupled Plasma Optical Emission Spectrometry analysis showed the highest Au uptake for plants treated with 5.0 microM IBA. The average recovery of Au with this treatment was significantly greater than the control treatment by 45.8 mg kg(-1) (155.7%). The other IBA concentrations (2.5 and 7.5 microM) also showed a significant increase in Au uptake compared to the control plants by 14.7 mg kg(-1) (50%) and 42.5 mg kg(-1) (144.5%) respectively. A similar trend of Au accumulation was recorded in the roots of B. juncea plants. This study conducted in solution culture suggests that plant growth regulators can play a significant role in improving phytoextraction of Au.
Benzyladenine (BA) is the most widely used cytokinin in the micropropagation industry due to its ... more Benzyladenine (BA) is the most widely used cytokinin in the micropropagation industry due to its effectiveness and affordability. It, however, has disadvantages such as genetic alteration and abnormal growth in some plants. Naturally occurring zeatin on the other hand is not as widely used as BA and is far more expensive. The use of meta-topolin and its derivatives as alternatives
Industrialisation has resulted in large-scale production of anthropogenic pollutants, particularl... more Industrialisation has resulted in large-scale production of anthropogenic pollutants, particularly heavy metals. Existing industrial techniques for the purification of waste water are expensive. A cheaper alternative may be 'bioremoval', that is, the accumulation and concentration of pollutants from aqueous solutions using biological material. The adsorption of copper, zinc and cadmium using two dried seaweeds Ecklonia maxima and Laminaria pallida (order Laminariales) and Kelpak waste (also made from Ecklonia maxima), a byproduct from the manufacture of the seaweed concentrate Kelpak, were investigated under laboratory conditions, to determine some factors affecting heavy metal adsorption. Ion adsorption from single and mixed metal ion solutions of 10mgl− 1 and 100mgl− 1 containing copper, zinc and cadmium were tested at various temperatures and pH. Optimum adsorption occurred at pH 3 and pH 7 and Kelpak waste had equal or superior adsorption ability to dried Ecklonia maxima and Laminaria pallida, particularly for copper. Optimum adsorption occurred at temperatures of 20°C and 30°C. Heavy metal adsorption trends by the individual seaweed biosorbent remained constant regardless of the species of anion present. Drying of the experimental material (fan air and oven drying at 85°C) prior to adsorption cycles resulted in more efficient ion uptake, particularly after additional rehydration. Heavy metal uptake was monitored over a number of semi-continuous adsorption cycles, using the same biomasses. Ion uptake was the most efficient after 2–4 adsorption cycles.
Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminate... more Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminated with metals from mining activities, the danger of human intoxication exists. An experiment with plants exposed to cadmium (Cd) was performed to investigate the response of M. plumbea to this heavy metal, its uptake and translocation to plant organs and reaction of root tissues. Plants grown from seeds were cultivated in controlled conditions. Hydroponic cultivation is not suitable for this species as roots do not tolerate aquatic conditions, and additional stress by Cd treatment results in total root growth inhibition and death. After cultivation in perlite the plants exposed to 1 and 5 mg Cd L(-1) in half-strength Hoagland's solution were compared with control plants. Growth parameters were evaluated, Cd content was determined by inductively coupled plasma mass spectroscopy (ICP-MS) and root structure was investigated using various staining procedures, including the fluorescent st...
Javier Abadia Chedly Abdelly Patrick Achard Jeffrey W. Adelberg Randy Allen Nick Amrhein Klaus Ap... more Javier Abadia Chedly Abdelly Patrick Achard Jeffrey W. Adelberg Randy Allen Nick Amrhein Klaus Appenroth Rich Arteca Kozi Asada Folkard Asch Muhammed Ashraf Frantisek Baluska Graham Barry John Beeching Maria Patricia Benavides Ajaya Biswal Miguel Angel Blazquez Eduardo Blumwald M. Bolker Miguel Botella Helen Bramley Adina Breiman Ray Bressan Q. Cai James J. Campanella Jorge Canhoto A. Elizabete Carmo-Silva Paula Casati Fabricio Cassan Ming-Tsair Chan Ming-Shun Chen Lailiang Cheng Hyun-Taeg Cho Won-Gyu Choi Jyh-Ching Chou Morris Cline Steve Clouse Jerry D. Cohen Francisco Javier Corpas Grant Cramer Teresa Cutright Christopher Davies Peter Davies Luigi De Bellis Geert-Jan De Klerk Laura de la Canal Darleen A. DeMason Michael Deyholos H. S. Dhaliwal Nihal Dharmasiri Ian C. Dodd Frances DuPont David Ehret R.J. Neil Emery Eric van der Graaff Carolina Escobar Louise Ferguson Helena Fernandez Raffaella Filippini Judith Fliegmann Ryo Funada Susheng Gan Jose L. Garcia-Martinez J. Garcia-Mina Gary Gardner Lauren Garner Hernâni Gerós Anthony Glass Martin Goffinet Yolanda Gogorcena Albensio Gomes Silveira Dennis Greer Patrick Gulick Edward Gwozdz Mohammad-Reza Hajirezaeir David Hannapel Karl H. Hasenstein Bettina Hause Dirk B. Hays Xiaodong Huang Zhonglian Huang Yang Ju Im Tari Irma Takahiro Ishikawa Abdelbagi Ismail Thomas Jack Mike Jackson Mukesh Jain Cheruth Abdul Jaleel Tibor Janda Christer Jansson Dominique Job Michelle Jones Raymond Jongschaap Miroslav Kaminek Ching-Huei Kao
... WA Stirk* & J. Van Staden Natal University Research Unit for Plant Growth and Development... more ... WA Stirk* & J. Van Staden Natal University Research Unit for Plant Growth and Development, Department of Botany, University of Natal Pietermaritzburg, Private Bag X01, Scottsville ... Indole-butyric acid (IBA) over a concentration range of 10-7-10-4 M was used as the standard. ...
The use of plant growth regulators is well established and they are used in many fields of plant ... more The use of plant growth regulators is well established and they are used in many fields of plant science for enhancing growth. Brassica juncea plants were treated with 2.5, 5.0 and 7.5 microM auxin indole-3-butyric acid (IBA), which promotes rooting. The IBA-treated plants were also sprayed with 100 microM gibberellic acid (GA3) and kinetin (Kin) to increase leaf-foliage. Gold (I) chloride (AuCl) was added to the growth medium of plants to achieve required gold concentration. The solubilizing agent ammonium thiocyanate (1 g kg(-1)) (commonly used in mining industries to solubilize gold) was added to the nutrient solution after six weeks of growth and, two weeks later, plants were harvested. Plant growth regulators improved shoot and root dry biomass of B. juncea plants. Inductively Coupled Plasma Optical Emission Spectrometry analysis showed the highest Au uptake for plants treated with 5.0 microM IBA. The average recovery of Au with this treatment was significantly greater than the control treatment by 45.8 mg kg(-1) (155.7%). The other IBA concentrations (2.5 and 7.5 microM) also showed a significant increase in Au uptake compared to the control plants by 14.7 mg kg(-1) (50%) and 42.5 mg kg(-1) (144.5%) respectively. A similar trend of Au accumulation was recorded in the roots of B. juncea plants. This study conducted in solution culture suggests that plant growth regulators can play a significant role in improving phytoextraction of Au.
Benzyladenine (BA) is the most widely used cytokinin in the micropropagation industry due to its ... more Benzyladenine (BA) is the most widely used cytokinin in the micropropagation industry due to its effectiveness and affordability. It, however, has disadvantages such as genetic alteration and abnormal growth in some plants. Naturally occurring zeatin on the other hand is not as widely used as BA and is far more expensive. The use of meta-topolin and its derivatives as alternatives
Industrialisation has resulted in large-scale production of anthropogenic pollutants, particularl... more Industrialisation has resulted in large-scale production of anthropogenic pollutants, particularly heavy metals. Existing industrial techniques for the purification of waste water are expensive. A cheaper alternative may be 'bioremoval', that is, the accumulation and concentration of pollutants from aqueous solutions using biological material. The adsorption of copper, zinc and cadmium using two dried seaweeds Ecklonia maxima and Laminaria pallida (order Laminariales) and Kelpak waste (also made from Ecklonia maxima), a byproduct from the manufacture of the seaweed concentrate Kelpak, were investigated under laboratory conditions, to determine some factors affecting heavy metal adsorption. Ion adsorption from single and mixed metal ion solutions of 10mgl− 1 and 100mgl− 1 containing copper, zinc and cadmium were tested at various temperatures and pH. Optimum adsorption occurred at pH 3 and pH 7 and Kelpak waste had equal or superior adsorption ability to dried Ecklonia maxima and Laminaria pallida, particularly for copper. Optimum adsorption occurred at temperatures of 20°C and 30°C. Heavy metal adsorption trends by the individual seaweed biosorbent remained constant regardless of the species of anion present. Drying of the experimental material (fan air and oven drying at 85°C) prior to adsorption cycles resulted in more efficient ion uptake, particularly after additional rehydration. Heavy metal uptake was monitored over a number of semi-continuous adsorption cycles, using the same biomasses. Ion uptake was the most efficient after 2–4 adsorption cycles.
Uploads
Papers by Wendy Stirk