The chestnuts genus(Castanea spp.)is comprised of economically important trees native to the Northern hemisphere that are used as food and hardwood timber.Here,a very efficient method for micropropagation of European&...The chestnuts genus(Castanea spp.)is comprised of economically important trees native to the Northern hemisphere that are used as food and hardwood timber.Here,a very efficient method for micropropagation of European×Japanese chestnut hybrids(Castanea sativa×C.crenata)is described.Woody Plant Medium was used as the basal medium.In vitro shoots of four rootstock cultivars were micropropagated without shoot-tip necrosis on multiplication medium containing 5.7 or 11.4μmol·L^(−1)zeatin riboside,and were rooted on rooting medium containing 2.46μmol·L^(−1)indolebutyric acid.Monthly shootmultiplication rates for each cultivarwere 2–5 folds.In vitro rooting percentages for four cultivars were 87%for‘Maraval’,67%for‘Marigoule’,93%for‘Marsol’,and 97%for‘Précoce Migoule’.Within a 5 week period,80%–95%of rooted shoots were successfully acclimated under high humidity conditions after they were planted in either soil or rockwool.展开更多
Cytokinins are plant hormones that play an integral role in multiple aspects of plant growth and development. The biological functions of cytokinins in mammalian systems are, however, largely uncharacterized. The natu...Cytokinins are plant hormones that play an integral role in multiple aspects of plant growth and development. The biological functions of cytokinins in mammalian systems are, however, largely uncharacterized. The naturally occurring cytokinin zeatin riboside has recently been demonstrated to activate the mammalian adenosine A2A receptor, which is broadly expressed by various cell types including immune system cells, with the activation of the A2AR playing a role in the regulation of cells involved in both innate and adaptive immunity. We show for the first time that zeatin riboside modulates mammalian immune system activity via an A2AR-dependent mechanism. Specifically, zeatin riboside treatment induces the production of cyclic adenosine monophosphate （cAMP） by T lymphocytes and inhibits the production by CD3^＋CD4^＋ T cells of interferon （IFN）-γ, IL-2, tumor-necrosis factor （TNF）-α, IL-4 and IL-13, and the production by CD3^＋CD8^＋ T cells of IFN-γ, IL-2 and TNF-α. Additionally, the upregulation of CD25, CD69 and CD40L by activated T lymphocytes is modulated by zeatin riboside. Zeatin riboside treatment also potently inhibits thioglycollate-induced peritoneal leukocytosis. The immunomodulatory activities of zeatin riboside are blocked by co-treatment with the selective A2AR antagonist ZM241385. These data suggest that zeatin riboside possesses therapeutic potential as a mammalian immunomodulatory agent.展开更多
Alternate bearing habit, a common phenomenon prevalent in some of the fruit trees is observed in black pepper variety Panniyur-1 also. In this study, an attempt was made to investigate the role of carbohydrates, miner...Alternate bearing habit, a common phenomenon prevalent in some of the fruit trees is observed in black pepper variety Panniyur-1 also. In this study, an attempt was made to investigate the role of carbohydrates, mineral nutrients and plant hormones (IAA and zeatin riboside) in alternate bearing in Panniyur-1 variety. The experiment was conducted for three consecutive years at Murugarajendra estate, Madikeri, Karnataka, India (12.42。N, 75.73。E). Carbohydrate, mineral nutrient and plant hormone (IAA and zeatin riboside) statuses of the leaves as well as fruiting branches (stem) were compared between good fruiting year (on year) and low fruiting year (off year). Results revealed that concentration of mineral nutrients in leaves was more during on year compared to off year while the reverse was true on the stem. Both stem and leaf metabolite levels at harvest were higher in off year compared to on year suggesting that remobilization of nutrients to the developing berries must have been affected during off year, thus leading to accumulation of more nutrients at harvest in off year compared to on year. Leaf had higher concentration of most of mineral nutrients compared to stem. Spraying of 1% solution of complex fertilizer 19:19:19 (percent N:P:K) three times at an interval of 3 weeks from flower primordial initiation to flowering period enhanced the yield to the extent of around 30% during off year. Auxin to cytokinin ratio was 6.6 and 6.1 in on year and 6.3 and 5.7 in off year at flowering and 3 months after flowering respectively, suggesting that this ratio itself may not play a major role in flowering during on and off years, though the ratio was slightly more during on year. Results of the study indicate that efficient utilization of metabolites and nutrients in on year may render vine weak in the subsequent year coupled with poor remobilization into developing berries, which could make it an off year.展开更多
目的研究混合丛枝菌根(AM)真菌不同接种时期对滇重楼Paris polyphylla Smith var. yunnanensis幼苗内源激素含量的影响。方法室内盆栽法,分别将滇重楼种子、1年生苗、2年生苗接种混合AM真菌,于灭菌土壤基质中进行共生培养,采用高效液相...目的研究混合丛枝菌根(AM)真菌不同接种时期对滇重楼Paris polyphylla Smith var. yunnanensis幼苗内源激素含量的影响。方法室内盆栽法,分别将滇重楼种子、1年生苗、2年生苗接种混合AM真菌,于灭菌土壤基质中进行共生培养,采用高效液相色谱法测定内源激素玉米素核苷(ZR)、赤霉素(GA)、吲哚乙酸(IAA)和脱落酸(ABA)含量。结果混合AM真菌对不同时期,不同种源的滇重楼根状茎和根中内源激素ZR、GA、IAA、ABA含量变化的影响不尽相同。整体上,与对照组比较,野生种源和栽培种源滇重楼根状茎和根的ZR和GA内源激素含量均呈增加趋势,ABA含量均呈减少趋势。滇重楼根状茎和根中IAA/ABA、GA/ABA、ZR/ABA增大。结论 1年生苗期接种S2、S6型混合AM真菌,对促进滇重楼幼苗根状茎和根生长的综合效果最佳。展开更多
基金the Michigan State University-Ernie and Mabel Rogers Endowment.
文摘The chestnuts genus(Castanea spp.)is comprised of economically important trees native to the Northern hemisphere that are used as food and hardwood timber.Here,a very efficient method for micropropagation of European×Japanese chestnut hybrids(Castanea sativa×C.crenata)is described.Woody Plant Medium was used as the basal medium.In vitro shoots of four rootstock cultivars were micropropagated without shoot-tip necrosis on multiplication medium containing 5.7 or 11.4μmol·L^(−1)zeatin riboside,and were rooted on rooting medium containing 2.46μmol·L^(−1)indolebutyric acid.Monthly shootmultiplication rates for each cultivarwere 2–5 folds.In vitro rooting percentages for four cultivars were 87%for‘Maraval’,67%for‘Marigoule’,93%for‘Marsol’,and 97%for‘Précoce Migoule’.Within a 5 week period,80%–95%of rooted shoots were successfully acclimated under high humidity conditions after they were planted in either soil or rockwool.
文摘Cytokinins are plant hormones that play an integral role in multiple aspects of plant growth and development. The biological functions of cytokinins in mammalian systems are, however, largely uncharacterized. The naturally occurring cytokinin zeatin riboside has recently been demonstrated to activate the mammalian adenosine A2A receptor, which is broadly expressed by various cell types including immune system cells, with the activation of the A2AR playing a role in the regulation of cells involved in both innate and adaptive immunity. We show for the first time that zeatin riboside modulates mammalian immune system activity via an A2AR-dependent mechanism. Specifically, zeatin riboside treatment induces the production of cyclic adenosine monophosphate （cAMP） by T lymphocytes and inhibits the production by CD3^＋CD4^＋ T cells of interferon （IFN）-γ, IL-2, tumor-necrosis factor （TNF）-α, IL-4 and IL-13, and the production by CD3^＋CD8^＋ T cells of IFN-γ, IL-2 and TNF-α. Additionally, the upregulation of CD25, CD69 and CD40L by activated T lymphocytes is modulated by zeatin riboside. Zeatin riboside treatment also potently inhibits thioglycollate-induced peritoneal leukocytosis. The immunomodulatory activities of zeatin riboside are blocked by co-treatment with the selective A2AR antagonist ZM241385. These data suggest that zeatin riboside possesses therapeutic potential as a mammalian immunomodulatory agent.
文摘Alternate bearing habit, a common phenomenon prevalent in some of the fruit trees is observed in black pepper variety Panniyur-1 also. In this study, an attempt was made to investigate the role of carbohydrates, mineral nutrients and plant hormones (IAA and zeatin riboside) in alternate bearing in Panniyur-1 variety. The experiment was conducted for three consecutive years at Murugarajendra estate, Madikeri, Karnataka, India (12.42。N, 75.73。E). Carbohydrate, mineral nutrient and plant hormone (IAA and zeatin riboside) statuses of the leaves as well as fruiting branches (stem) were compared between good fruiting year (on year) and low fruiting year (off year). Results revealed that concentration of mineral nutrients in leaves was more during on year compared to off year while the reverse was true on the stem. Both stem and leaf metabolite levels at harvest were higher in off year compared to on year suggesting that remobilization of nutrients to the developing berries must have been affected during off year, thus leading to accumulation of more nutrients at harvest in off year compared to on year. Leaf had higher concentration of most of mineral nutrients compared to stem. Spraying of 1% solution of complex fertilizer 19:19:19 (percent N:P:K) three times at an interval of 3 weeks from flower primordial initiation to flowering period enhanced the yield to the extent of around 30% during off year. Auxin to cytokinin ratio was 6.6 and 6.1 in on year and 6.3 and 5.7 in off year at flowering and 3 months after flowering respectively, suggesting that this ratio itself may not play a major role in flowering during on and off years, though the ratio was slightly more during on year. Results of the study indicate that efficient utilization of metabolites and nutrients in on year may render vine weak in the subsequent year coupled with poor remobilization into developing berries, which could make it an off year.
文摘目的研究混合丛枝菌根(AM)真菌不同接种时期对滇重楼Paris polyphylla Smith var. yunnanensis幼苗内源激素含量的影响。方法室内盆栽法,分别将滇重楼种子、1年生苗、2年生苗接种混合AM真菌,于灭菌土壤基质中进行共生培养,采用高效液相色谱法测定内源激素玉米素核苷(ZR)、赤霉素(GA)、吲哚乙酸(IAA)和脱落酸(ABA)含量。结果混合AM真菌对不同时期,不同种源的滇重楼根状茎和根中内源激素ZR、GA、IAA、ABA含量变化的影响不尽相同。整体上,与对照组比较,野生种源和栽培种源滇重楼根状茎和根的ZR和GA内源激素含量均呈增加趋势,ABA含量均呈减少趋势。滇重楼根状茎和根中IAA/ABA、GA/ABA、ZR/ABA增大。结论 1年生苗期接种S2、S6型混合AM真菌,对促进滇重楼幼苗根状茎和根生长的综合效果最佳。
