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G Tallman - One of the best experts on this subject based on the ideXlab platform.
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regeneration of plants from cultured guard cell protoplasts of Nicotiana glauca graham
Plant Science, 1994Co-Authors: Prateek Sahgal, Gregory V Martinez, Cathy Roberts, G TallmanAbstract:Experiments were performed to optimize conditions for culturing guard cell protoplasts of Nicotiana glauca and to determine whether cultured guard cell protoplasts were totipotent. Guard cell protoplasts were isolated from adaxial epidermal tissue of leaves of Nicotiana glauca grown under fluorescent light (800–900 μmol m−2 s−1 of photons of photosynthetically active radiation). To increase the probability that guard cells were of uniform osmotic potential at the time leaves were harvested, leaves were collected in darkness, just before the beginning of each light period. Protoplasts were cultured in liquid media similar to those used for culturing mesophyll cell protoplasts of Nicotiana tabacum but of modified pH and KCl, CaCl2, sucrose and glycine concentrations. Concentrations of growth regulators were 0.3 mg 1−1 α-napthaleneacetic acid (NAA) and 0.075 mg 1−1 of 6-benzylaminopurine (BAP). Protoplasts were incubated in darkness at 25°C in 8-well microchamber slides at a density of 1.25 × 105 cells ml−1. Cell divisions began within 72–96 h of initiation of cultures. After 96 h, cell survival averaged 57% of the initial number of cells (n, 20; range, 36–84%). After 8–10 weeks of culture, cell colonies were transferred to a callus initiation medium containing agar and incubated under continuous white fluorescent light (25 μmol m−2 s−1 of photons of photosynthetically active radiation) for another 8–10 weeks. Green callus tissue was then transferred to a commercial callus growth medium and incubated under similar conditions. After 8–10 weeks of further growth, callus was transferred to a commercial shoot differentiation medium and incubated similarly. Multiple shoots appeared within 2 weeks. Shoots were transferred to a root differentiation medium and cultured under the conditions described above. When roots were sufficiently developed (6–8 weeks), plants were transplanted to soil and grown in a growth chamber. We conclude that guard cell protoplasts can be made to survive in culture at high percentages and that cultured guard cell protoplasts of Nicotiana glauca are totipotent.
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division of guard cell protoplasts of Nicotiana glauca graham in liquid cultures
Plant Cell and Environment, 1991Co-Authors: W Cupples, J Lee, G TallmanAbstract:Abstract. Guard cells are uniquely differentiated to transduce signals into the metabolic and ion transport processes that result in turgor-driven stomatal movements. We tested the hypothesis that these highly specialized cells are terminally differentiated. Guard cell protoplasts were isolated from abaxial epidermal tissue of leaves of Nicotiana glauca (Graham) and cultured in a medium designed for culturing mesophyll protoplasts of Nicotiana tabacum. Protoplasts were incubated at densities of 2–5 × 1011 cells m−3 in eight-well microchamber slides under 50μmol m−2 s−1 of photons of continuous fluorescent light at 25°C. When the medium was modified by the addition of 100mol m−3 of sucrose and by buffering with 10mol m−3 of MES buffer at pH 6.1, cell division began within 96h of the time the culture was initiated. After 9d of culture, 80% of surviving cells had synthesized new cell walls, had dedifferentiated, and were dividing to form small colonies. Callus tissue was visible after 4–5 weeks. We conclude that guard cells of Nicotiana glauca are not terminally differentiated, and that guard cell protoplasts of this species have the capacity to grow, synthesize cell walls and divide.
Ido Izhaki - One of the best experts on this subject based on the ideXlab platform.
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pollination ecology of the invasive tree tobacco Nicotiana glauca comparisons across native and non native ranges
Journal of pollination ecology, 2012Co-Authors: Jeff Ollerton, Stella Watts, Shawn Connerty, Julia Lock, Leah Parker, Ian Wilson, Sheila Schueller, Julieta Nattero, Andrea Aristides Cocucci, Ido IzhakiAbstract:Interactions with pollinators are thought to play a significant role in determining whether plant species become invasive, and ecologically generalised species are predicted to be more likely to invade than more specialised species. Using published and unpublished data we assessed the floral biology and pollination ecology of the South American native Nicotiana glauca (Solanaceae) which has become a significant invasive of semi-arid parts of the world. In regions where specialised bird pollinators are available, for example hummingbirds in California and sunbirds in South Africa and Israel, N. glauca interacts with these local pollinators and sets seed by both out-crossing and selfing. In areas where there are no such birds, such as the Canary Islands and Greece, abundant viable seed is set by selfing, facilitated by the shorter stigma-anther distance compared to plants in native populations. Surprisingly, in these areas without pollinating birds, the considerable nectar resources are only rarely exploited by other flower visitors such as bees or butterflies, either legitimately or by nectar robbing. We conclude that Nicotiana glauca is a successful invasive species outside of its native range, despite its functionally specialised hummingbird pollination system, because it has evolved to become more frequently self pollinating in areas where it is introduced. Its invasion success is not predictable from what is known of its interactions with pollinators in its home range.
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limited ability of palestine sunbirds nectarinia osea to cope with pyridine alkaloids in nectar of tree tobacco Nicotiana glauca
Functional Ecology, 2004Co-Authors: Michael Wink, Shai Markman, H Tadmormelamed, A Arieli, Melanie Distl, Ido IzhakiAbstract:Summary 1. Secondary compounds are common in floral nectar but their relative effects on nectar consumption and utilization in nectarivorous birds are unclear. 2. We studied the effect of two pyridine alkaloids, nicotine and anabasine, present in Tree Tobacco ( Nicotiana glauca ) nectar, on food consumption, gut transit time and sugar assimilation efficiency of the Palestine Sunbird ( Nectarinia osea ), a pollinator of N. glauca in east Mediterranean ecosystems. 3. Sunbirds demonstrated dose-dependent deterrence; they were not deterred by the lowest natural concentrations of these alkaloids in nectar (0·1 ppm nicotine and 0·6 ppm anabasine) but they were significantly deterred by the average concentrations detected in nectar (0·5 ppm nicotine and 5 ppm anabasine). 4. The two pyridine alkaloids reduced gut transit time (by 30‐42%) and sugar assimilation efficiency (by 9‐17%) compared with the control alkaloid-free diet. 5. Sunbirds are able to cope with low, but not average, concentrations of nicotine and anabasine in N. glauca nectar. If sunbirds are efficient pollinators of N. glauca they may induce selection on it to reduce pyridine alkaloid production in the nectar. Alternatively, high concentrations in some N. glauca plants may lead the birds to visit more plants with lower alkaloid concentrations. Hence, they will be more efficient pollinators, especially if other nectar-producing plants are scarce.
Shai Markman - One of the best experts on this subject based on the ideXlab platform.
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Immediate effects of nectar robbing by Palestine sunbirds (Nectarinia osea) on nectar alkaloid concentrations in tree tobacco (Nicotiana glauca).
Journal of chemical ecology, 2014Co-Authors: Rainee L. Kaczorowski, Avi Koplovich, Frank Sporer, Michael Wink, Shai MarkmanAbstract:Plant secondary metabolites (PSMs), such as alkaloids, are often found in many parts of a plant, including flowers, providing protection to the plant from various types of herbivores or microbes. PSMs are also present in the floral nectar of many species, but typically at lower concentrations than in other parts of the plant. Nectar robbers often damage floral tissue to access the nectar. By doing so, these nectar robbers may initiate an increase of PSMs in the floral nectar. It is often assumed that it takes at least a few hours before the plant demonstrates an increase in PSMs. Here, we addressed the question of whether PSMs in the floral tissue are immediately being released into the floral nectar following nectar robbing. To address this research question, we investigated whether there was an immediate effect of nectar robbing by the Palestine Sunbird (Nectarinia osea) on the concentration of nectar alkaloids, nicotine and anabasine, in Tree Tobacco (Nicotiana glauca). We found that the concentration of anabasine, but not nicotine, significantly increased in floral nectar immediately following simulated nectar robbing. These findings suggest that nectar robbers could be ingesting greater amounts of PSMs than they would if they visit flowers legitimately. As a consequence, increased consumption of neurotoxic nectar alkaloids or other PSMs could have negative effects on the nectar robber.
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limited ability of palestine sunbirds nectarinia osea to cope with pyridine alkaloids in nectar of tree tobacco Nicotiana glauca
Functional Ecology, 2004Co-Authors: Michael Wink, Shai Markman, H Tadmormelamed, A Arieli, Melanie Distl, Ido IzhakiAbstract:Summary 1. Secondary compounds are common in floral nectar but their relative effects on nectar consumption and utilization in nectarivorous birds are unclear. 2. We studied the effect of two pyridine alkaloids, nicotine and anabasine, present in Tree Tobacco ( Nicotiana glauca ) nectar, on food consumption, gut transit time and sugar assimilation efficiency of the Palestine Sunbird ( Nectarinia osea ), a pollinator of N. glauca in east Mediterranean ecosystems. 3. Sunbirds demonstrated dose-dependent deterrence; they were not deterred by the lowest natural concentrations of these alkaloids in nectar (0·1 ppm nicotine and 0·6 ppm anabasine) but they were significantly deterred by the average concentrations detected in nectar (0·5 ppm nicotine and 5 ppm anabasine). 4. The two pyridine alkaloids reduced gut transit time (by 30‐42%) and sugar assimilation efficiency (by 9‐17%) compared with the control alkaloid-free diet. 5. Sunbirds are able to cope with low, but not average, concentrations of nicotine and anabasine in N. glauca nectar. If sunbirds are efficient pollinators of N. glauca they may induce selection on it to reduce pyridine alkaloid production in the nectar. Alternatively, high concentrations in some N. glauca plants may lead the birds to visit more plants with lower alkaloid concentrations. Hence, they will be more efficient pollinators, especially if other nectar-producing plants are scarce.
H Tadmormelamed - One of the best experts on this subject based on the ideXlab platform.
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limited ability of palestine sunbirds nectarinia osea to cope with pyridine alkaloids in nectar of tree tobacco Nicotiana glauca
Functional Ecology, 2004Co-Authors: Michael Wink, Shai Markman, H Tadmormelamed, A Arieli, Melanie Distl, Ido IzhakiAbstract:Summary 1. Secondary compounds are common in floral nectar but their relative effects on nectar consumption and utilization in nectarivorous birds are unclear. 2. We studied the effect of two pyridine alkaloids, nicotine and anabasine, present in Tree Tobacco ( Nicotiana glauca ) nectar, on food consumption, gut transit time and sugar assimilation efficiency of the Palestine Sunbird ( Nectarinia osea ), a pollinator of N. glauca in east Mediterranean ecosystems. 3. Sunbirds demonstrated dose-dependent deterrence; they were not deterred by the lowest natural concentrations of these alkaloids in nectar (0·1 ppm nicotine and 0·6 ppm anabasine) but they were significantly deterred by the average concentrations detected in nectar (0·5 ppm nicotine and 5 ppm anabasine). 4. The two pyridine alkaloids reduced gut transit time (by 30‐42%) and sugar assimilation efficiency (by 9‐17%) compared with the control alkaloid-free diet. 5. Sunbirds are able to cope with low, but not average, concentrations of nicotine and anabasine in N. glauca nectar. If sunbirds are efficient pollinators of N. glauca they may induce selection on it to reduce pyridine alkaloid production in the nectar. Alternatively, high concentrations in some N. glauca plants may lead the birds to visit more plants with lower alkaloid concentrations. Hence, they will be more efficient pollinators, especially if other nectar-producing plants are scarce.
Michael Wink - One of the best experts on this subject based on the ideXlab platform.
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Immediate effects of nectar robbing by Palestine sunbirds (Nectarinia osea) on nectar alkaloid concentrations in tree tobacco (Nicotiana glauca).
Journal of chemical ecology, 2014Co-Authors: Rainee L. Kaczorowski, Avi Koplovich, Frank Sporer, Michael Wink, Shai MarkmanAbstract:Plant secondary metabolites (PSMs), such as alkaloids, are often found in many parts of a plant, including flowers, providing protection to the plant from various types of herbivores or microbes. PSMs are also present in the floral nectar of many species, but typically at lower concentrations than in other parts of the plant. Nectar robbers often damage floral tissue to access the nectar. By doing so, these nectar robbers may initiate an increase of PSMs in the floral nectar. It is often assumed that it takes at least a few hours before the plant demonstrates an increase in PSMs. Here, we addressed the question of whether PSMs in the floral tissue are immediately being released into the floral nectar following nectar robbing. To address this research question, we investigated whether there was an immediate effect of nectar robbing by the Palestine Sunbird (Nectarinia osea) on the concentration of nectar alkaloids, nicotine and anabasine, in Tree Tobacco (Nicotiana glauca). We found that the concentration of anabasine, but not nicotine, significantly increased in floral nectar immediately following simulated nectar robbing. These findings suggest that nectar robbers could be ingesting greater amounts of PSMs than they would if they visit flowers legitimately. As a consequence, increased consumption of neurotoxic nectar alkaloids or other PSMs could have negative effects on the nectar robber.
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limited ability of palestine sunbirds nectarinia osea to cope with pyridine alkaloids in nectar of tree tobacco Nicotiana glauca
Functional Ecology, 2004Co-Authors: Michael Wink, Shai Markman, H Tadmormelamed, A Arieli, Melanie Distl, Ido IzhakiAbstract:Summary 1. Secondary compounds are common in floral nectar but their relative effects on nectar consumption and utilization in nectarivorous birds are unclear. 2. We studied the effect of two pyridine alkaloids, nicotine and anabasine, present in Tree Tobacco ( Nicotiana glauca ) nectar, on food consumption, gut transit time and sugar assimilation efficiency of the Palestine Sunbird ( Nectarinia osea ), a pollinator of N. glauca in east Mediterranean ecosystems. 3. Sunbirds demonstrated dose-dependent deterrence; they were not deterred by the lowest natural concentrations of these alkaloids in nectar (0·1 ppm nicotine and 0·6 ppm anabasine) but they were significantly deterred by the average concentrations detected in nectar (0·5 ppm nicotine and 5 ppm anabasine). 4. The two pyridine alkaloids reduced gut transit time (by 30‐42%) and sugar assimilation efficiency (by 9‐17%) compared with the control alkaloid-free diet. 5. Sunbirds are able to cope with low, but not average, concentrations of nicotine and anabasine in N. glauca nectar. If sunbirds are efficient pollinators of N. glauca they may induce selection on it to reduce pyridine alkaloid production in the nectar. Alternatively, high concentrations in some N. glauca plants may lead the birds to visit more plants with lower alkaloid concentrations. Hence, they will be more efficient pollinators, especially if other nectar-producing plants are scarce.