In a greenhouse experiment plasticity of clonal growth and clonal morphology of the stoloniferous rosette herb Halerpestes nahenica Ovcz. in response to differing levels of light intensity and nutrient availability wa...In a greenhouse experiment plasticity of clonal growth and clonal morphology of the stoloniferous rosette herb Halerpestes nahenica Ovcz. in response to differing levels of light intensity and nutrient availability was studied. Total plant dry weight, leaf area of primary ramets, total number of ramets and of stolons, and total stolon length were significantly reduced, while specific internode length and specific petiole length significantly increased under deep shading (6.25% of high light intensity, 5.3% of full daylight) or under low nutrient availability. Under low nutrient availability, mean stolon internode length of H. ruthenica was significantly larger while branching intensity and number of ramets smaller than those under high nutrient availability. These responses are consistent with the foraging model of clonal plants, indicating that H. nahenica is able to forage nutrients through the plastic responses of clonal growth and clonal. morphology when it grows in heterogeneous environments. However, under deep shading, both mean stolon internode length and mean petiole length were significantly reduced, which disagrees with the findings of many other stoloniferous herbs in response to low or medium levels of shading (ca. 13%-75% of high light intensity, >10% of full daylight), suggesting that under deep shading stoloniferous herbs may not forage light through the plastic responses of spacer length. Many traits such as total plant dry weight, total number and length of stolons, total length of secondary and tertiary stolons. total number of ramets, leaf area of primary ramets and branching intensity were markedly influenced by the interaction effect of light intensity and nutrient availability. Under high light intensity nutrient availability affected these traits more pronouncedly, however under low light intensity nutrient availability either did not affect or affected less markedly on these traits, indicating that fight intensity had significant effect on nutrient foraging in H. nahenica. Under deep shading or low nutrient availability, H. ruthenica may increase its mean stolon internode length by means of thinning stolon internodes (i.e., an increase in specific internode length), which provides it with more chance to escape from resource-poor sites.展开更多
The clonal growth pattern of Sabina vulgaris, a coniferous clonal plant in Mu Us sandland, Inner Mongolia Autonomous Region was surveyed. The results showed that with the stolon extending, internode length and branchi...The clonal growth pattern of Sabina vulgaris, a coniferous clonal plant in Mu Us sandland, Inner Mongolia Autonomous Region was surveyed. The results showed that with the stolon extending, internode length and branching angle decreased, the branching intensity increased gradually within the 3 m range from the edge of the shrub to its center along the stolon. Internode length, branching intensity and branching angle were 5.9 cm, 4.4 and 55.3°in the shrub, and 1.6 cm, 13.7 and 38.3°at the edge of the shrub, respectively. The clonal architecture exhibited plasticity. The internode length, branching intensity and ramet length changed with an exponential model with extention of the stolon. The stolon of S. vulgaris was monopodial branching, and each ramet should possess more than 3 adventitious roots. Ramets could take on the phenomenon of 搒elf-thinning?with clonal growth. There was a prior grade in allocation of the nutrients gained from heterogeneous space. The clonal architecture of S. vulgaris was the 搈ixed?type.展开更多
The suitability of models for describing the clonal growth of Trifolium repens population was discussed. The results showed that deterministic models were inadequate for describing its clonal growth, but the diffusion...The suitability of models for describing the clonal growth of Trifolium repens population was discussed. The results showed that deterministic models were inadequate for describing its clonal growth, but the diffusion models and the randomwalk models suited for the clonal growth characteristics of the population. And it was found that random-walk models were better than diffusion models for describing a population in an environment with rich natural resources, and the latter was better in a poor environment.展开更多
A multipurpose clone plant species, Hippophae rhamniodes has the capacity for indefinite longevity, although under successive drought stress it may often decline or die across large areas. Field trials were con- ducte...A multipurpose clone plant species, Hippophae rhamniodes has the capacity for indefinite longevity, although under successive drought stress it may often decline or die across large areas. Field trials were con- ducted over 2 years to examine the effects of varied irrigation intensities on modular growth and clonal propagation in a semi-arid area. Irrigation levels included a control, as well as two, four and six times the volume of water that was typically received via local annual average precipitation. Irrigation intensity significantly influenced clonal propagation capacity （number of daughter ramets）, aboveground modular growth （height, base diameter, and crown width）, belowground modular growth included root nodule dry weight, stretching capacity of lateral roots （length of the longest lateral roots, and diameter of first-grade lateral roots）, and branching intensity of lateral roots （number of lateral roots bifurcation grade, number of first- grade lateral roots）. The modular growth and the density of daughter ramets were small under non-irrigation or low irrigation, and became larger with increased irrigation intensity. Beyond a certain threshold, however, further increases in irrigation intensity resulted in a reversion to the development. The optimal irrigation intensities for growth and propagation were 3.48-5.29 times the volume of nominal local annual average precipitation. There were effects of irrigation intensities on the positive significant correlations between aboveground and belowground modular growths, and on clonal propagation capacities. Under various water treatments, H. rhamnoides may adapt to the environment through the regulation of growth and propagation. We concluded that water shortages act to weaken the growth and propagation of H. rhamniodes plantations.展开更多
The life histories of 429 individual epidermal keratinocyte clones picked at random were studied. Individual basal keratinocytes were derived from asynchronous rapidly proliferating subconfluent cultures propagated in...The life histories of 429 individual epidermal keratinocyte clones picked at random were studied. Individual basal keratinocytes were derived from asynchronous rapidly proliferating subconfluent cultures propagated in either a low calcium (0.1mM) or a high calcium (2mM) serum-free medium. Single-celled clones were isolated by seeding trypsin-EDTA dissociated cells into a Petri dish containing cloning chips. Chips with only one cell per chip were transferred into dishes containing either low calcium or high calcium growth factor replete serum-free medium. Clone formation was monitored microscopically and the number of cells in each colony tallied at least twice daily for further analysis. A total of 369 clones were established from seven different neonatal foreskin cell strains (A-F), and 60 clones were derived from one adult human skin cell strain (G). During a five-day culture interval, among 32 clones of strain A, 83% divided at least once, 50% divided once in 24 hours, 86% divided at least three times within three days, and more than 50% divided at least four to five times in five days. Of 231 clones amongst the other five cell strains (B-F), an average of 63% (±12 S,E) divided more than three times in an eight day period, the remainder divided either once, twice or not at all. Of the 106 clones of strain G, reared in high calcium serum-free medium, 67% divided more than three times in a six-day period, and 55% divided five or more times in 6 days. Clones derived from adult skin strain H had a lower clone forming potential with 70% dividing at least once in seven days, and only 30% dividing three or more times. By contrast, the average generation time (AvGT) for second and third passage keratinocytes derived from neonatal foreskin cultures was 24 hrs. Detailed dendrograms were constructed for many of the proliferating clones. The majority of clones expressed a synblastic division pattern with every cell dividing at least once per day. A fraction of clones either exceeded this circadian division rate or displayed a biphasic division pattern with all cells initially dividing once a day and then abruptly slowing to once every other day or to an intermediate rate. A minority of clones was committed to a few terminal divisions. The division patterns of the non-synblastic clones fit an alternating bifurcated branching mode of clonal expansion expressed by the Fibonacci sequence for numbers of accumulated cells per clone per day. These results were analyzed in terms of deterministic, probabilistic and a limit cycle oscillator models of cell division timing.展开更多
Lung cancer is the leading cause of death globally, besides recent advances in its management; it maintains a low 5-year survival rate of 15%. The discovery of epidermal growth factor receptor(EGFR) activating mutatio...Lung cancer is the leading cause of death globally, besides recent advances in its management; it maintains a low 5-year survival rate of 15%. The discovery of epidermal growth factor receptor(EGFR) activating mutations and the introduction of its tyrosine kinase inhibitors(TKIs) have expanded the treatment options for patients with non-small cell lung cancer. Nowadays, EGFR mutation testing is now a common routine for newly diagnosed lung cancer. First generation TKIs developed, erlotinib and gefitinib, were reversible ones. After a median of 14 mo, eventually all EGFR mutated patients develop resistance to reversible TKIs. Afatinib, dacomitinib and neratinib, second generation inhibitors, are selective and irreversible TKIs. Finally, third generation phase Ⅰclinical trials were performed, with lower toxicity profiles, and targeting with more precision the driving clone of this heterogeneous disease.展开更多
文摘In a greenhouse experiment plasticity of clonal growth and clonal morphology of the stoloniferous rosette herb Halerpestes nahenica Ovcz. in response to differing levels of light intensity and nutrient availability was studied. Total plant dry weight, leaf area of primary ramets, total number of ramets and of stolons, and total stolon length were significantly reduced, while specific internode length and specific petiole length significantly increased under deep shading (6.25% of high light intensity, 5.3% of full daylight) or under low nutrient availability. Under low nutrient availability, mean stolon internode length of H. ruthenica was significantly larger while branching intensity and number of ramets smaller than those under high nutrient availability. These responses are consistent with the foraging model of clonal plants, indicating that H. nahenica is able to forage nutrients through the plastic responses of clonal growth and clonal. morphology when it grows in heterogeneous environments. However, under deep shading, both mean stolon internode length and mean petiole length were significantly reduced, which disagrees with the findings of many other stoloniferous herbs in response to low or medium levels of shading (ca. 13%-75% of high light intensity, >10% of full daylight), suggesting that under deep shading stoloniferous herbs may not forage light through the plastic responses of spacer length. Many traits such as total plant dry weight, total number and length of stolons, total length of secondary and tertiary stolons. total number of ramets, leaf area of primary ramets and branching intensity were markedly influenced by the interaction effect of light intensity and nutrient availability. Under high light intensity nutrient availability affected these traits more pronouncedly, however under low light intensity nutrient availability either did not affect or affected less markedly on these traits, indicating that fight intensity had significant effect on nutrient foraging in H. nahenica. Under deep shading or low nutrient availability, H. ruthenica may increase its mean stolon internode length by means of thinning stolon internodes (i.e., an increase in specific internode length), which provides it with more chance to escape from resource-poor sites.
基金the National Natural Science Foundation of China(Grant No.30060069)
文摘The clonal growth pattern of Sabina vulgaris, a coniferous clonal plant in Mu Us sandland, Inner Mongolia Autonomous Region was surveyed. The results showed that with the stolon extending, internode length and branching angle decreased, the branching intensity increased gradually within the 3 m range from the edge of the shrub to its center along the stolon. Internode length, branching intensity and branching angle were 5.9 cm, 4.4 and 55.3°in the shrub, and 1.6 cm, 13.7 and 38.3°at the edge of the shrub, respectively. The clonal architecture exhibited plasticity. The internode length, branching intensity and ramet length changed with an exponential model with extention of the stolon. The stolon of S. vulgaris was monopodial branching, and each ramet should possess more than 3 adventitious roots. Ramets could take on the phenomenon of 搒elf-thinning?with clonal growth. There was a prior grade in allocation of the nutrients gained from heterogeneous space. The clonal architecture of S. vulgaris was the 搈ixed?type.
文摘The suitability of models for describing the clonal growth of Trifolium repens population was discussed. The results showed that deterministic models were inadequate for describing its clonal growth, but the diffusion models and the randomwalk models suited for the clonal growth characteristics of the population. And it was found that random-walk models were better than diffusion models for describing a population in an environment with rich natural resources, and the latter was better in a poor environment.
基金supported by the National Science Foundation of China(31070551/31570609)
文摘A multipurpose clone plant species, Hippophae rhamniodes has the capacity for indefinite longevity, although under successive drought stress it may often decline or die across large areas. Field trials were con- ducted over 2 years to examine the effects of varied irrigation intensities on modular growth and clonal propagation in a semi-arid area. Irrigation levels included a control, as well as two, four and six times the volume of water that was typically received via local annual average precipitation. Irrigation intensity significantly influenced clonal propagation capacity （number of daughter ramets）, aboveground modular growth （height, base diameter, and crown width）, belowground modular growth included root nodule dry weight, stretching capacity of lateral roots （length of the longest lateral roots, and diameter of first-grade lateral roots）, and branching intensity of lateral roots （number of lateral roots bifurcation grade, number of first- grade lateral roots）. The modular growth and the density of daughter ramets were small under non-irrigation or low irrigation, and became larger with increased irrigation intensity. Beyond a certain threshold, however, further increases in irrigation intensity resulted in a reversion to the development. The optimal irrigation intensities for growth and propagation were 3.48-5.29 times the volume of nominal local annual average precipitation. There were effects of irrigation intensities on the positive significant correlations between aboveground and belowground modular growths, and on clonal propagation capacities. Under various water treatments, H. rhamnoides may adapt to the environment through the regulation of growth and propagation. We concluded that water shortages act to weaken the growth and propagation of H. rhamniodes plantations.
文摘The life histories of 429 individual epidermal keratinocyte clones picked at random were studied. Individual basal keratinocytes were derived from asynchronous rapidly proliferating subconfluent cultures propagated in either a low calcium (0.1mM) or a high calcium (2mM) serum-free medium. Single-celled clones were isolated by seeding trypsin-EDTA dissociated cells into a Petri dish containing cloning chips. Chips with only one cell per chip were transferred into dishes containing either low calcium or high calcium growth factor replete serum-free medium. Clone formation was monitored microscopically and the number of cells in each colony tallied at least twice daily for further analysis. A total of 369 clones were established from seven different neonatal foreskin cell strains (A-F), and 60 clones were derived from one adult human skin cell strain (G). During a five-day culture interval, among 32 clones of strain A, 83% divided at least once, 50% divided once in 24 hours, 86% divided at least three times within three days, and more than 50% divided at least four to five times in five days. Of 231 clones amongst the other five cell strains (B-F), an average of 63% (±12 S,E) divided more than three times in an eight day period, the remainder divided either once, twice or not at all. Of the 106 clones of strain G, reared in high calcium serum-free medium, 67% divided more than three times in a six-day period, and 55% divided five or more times in 6 days. Clones derived from adult skin strain H had a lower clone forming potential with 70% dividing at least once in seven days, and only 30% dividing three or more times. By contrast, the average generation time (AvGT) for second and third passage keratinocytes derived from neonatal foreskin cultures was 24 hrs. Detailed dendrograms were constructed for many of the proliferating clones. The majority of clones expressed a synblastic division pattern with every cell dividing at least once per day. A fraction of clones either exceeded this circadian division rate or displayed a biphasic division pattern with all cells initially dividing once a day and then abruptly slowing to once every other day or to an intermediate rate. A minority of clones was committed to a few terminal divisions. The division patterns of the non-synblastic clones fit an alternating bifurcated branching mode of clonal expansion expressed by the Fibonacci sequence for numbers of accumulated cells per clone per day. These results were analyzed in terms of deterministic, probabilistic and a limit cycle oscillator models of cell division timing.
文摘Lung cancer is the leading cause of death globally, besides recent advances in its management; it maintains a low 5-year survival rate of 15%. The discovery of epidermal growth factor receptor(EGFR) activating mutations and the introduction of its tyrosine kinase inhibitors(TKIs) have expanded the treatment options for patients with non-small cell lung cancer. Nowadays, EGFR mutation testing is now a common routine for newly diagnosed lung cancer. First generation TKIs developed, erlotinib and gefitinib, were reversible ones. After a median of 14 mo, eventually all EGFR mutated patients develop resistance to reversible TKIs. Afatinib, dacomitinib and neratinib, second generation inhibitors, are selective and irreversible TKIs. Finally, third generation phase Ⅰclinical trials were performed, with lower toxicity profiles, and targeting with more precision the driving clone of this heterogeneous disease.
