观察了7 种牧草种子在8 个NaCl浓度:0(0 Mpa),21(-0.1 Mpa),66(-0.3 Mpa),110(-0.5 Mpa),150(-0.70 Mpa),200(-0.9 Mpa),267(-1.2 Mpa),334(-1.95 Mpa),445(-2.603Mpa) m m ol/L下的发芽率及胚根和胚芽的生长,将盐胁迫下未萌发种子移入...观察了7 种牧草种子在8 个NaCl浓度:0(0 Mpa),21(-0.1 Mpa),66(-0.3 Mpa),110(-0.5 Mpa),150(-0.70 Mpa),200(-0.9 Mpa),267(-1.2 Mpa),334(-1.95 Mpa),445(-2.603Mpa) m m ol/L下的发芽率及胚根和胚芽的生长,将盐胁迫下未萌发种子移入营养液中,观测它们在解除盐胁迫后发芽率、胚根和胚芽生长的恢复情况。结果表明,盐胁迫下,随盐浓度的增加,种子的发芽率呈下降趋势,但长穗偃麦草的发芽率几乎不受盐胁迫的影响,总体上它的胚芽和胚根长度随渗透势的降低而减少。21 m m ol/L的盐浓度对不同种的胚芽和胚根有不同的刺激作用。解除盐胁迫后,种子发芽率随原浓度的增加而增加,445 m m ol/L的高浓度对所有种的胚芽和胚根恢复生长最有利。因此,短时间,尤其是高浓度下的盐分锻炼,对种子的发芽及胚根和胚芽的生长有促进作用,但促进的幅度因种而异。生产实践中可用盐锻炼促进种子的发芽率,提高建植效果。展开更多
Seed plants have evolved to maintain the dormancy of freshly matured seeds until the appropriate time for germination. Seed dormancy and germination are distinct physiological processes, and the transition from dorman...Seed plants have evolved to maintain the dormancy of freshly matured seeds until the appropriate time for germination. Seed dormancy and germination are distinct physiological processes, and the transition from dormancy to germination is not only a critical developmental step in the life cycle of plants but is also impor- tant for agricultural production. These processes are precisely regulated by diverse endogenous hormones and environmental cues. Although ABA （abscisic acid） and GAs （gibberellins） are known to be the primary phytohormones that antagonistically regulate seed dormancy, recent findings demonstrate that another phytohormone, auxin, is also critical for inducing and maintaining seed dormancy, and therefore might act as a key protector of seed dormancy. In this review, we summarize our current understanding of the sophisticated molecular networks involving the critical roles of phytohormones in regulating seed dormancy and germination, in which AP2-domain-containing transcription factors play key roles. We also discuss the interactions （crosstalk） of diverse hormonal signals in seed dormancy and germination, focusing on the ABA/GA balance that constitutes the central node.展开更多
With the enhancement of copper （Cu） stress, the germination percentage of wheat seeds decreased gradually. Pretreatment with sodium hydrosulfide （NariS）, hydrogen sulfide （H2S） donor alleviated the inhibitory ef...With the enhancement of copper （Cu） stress, the germination percentage of wheat seeds decreased gradually. Pretreatment with sodium hydrosulfide （NariS）, hydrogen sulfide （H2S） donor alleviated the inhibitory effect of Cu stress in a dose- dependent manner; whereas little visible symptom was observed in germinating seeds and radicle tips cultured in NariS solutions. It was verified that H2S or HS- rather than other sulfur-containing components derived from NariS attribute to the potential role in promoting seed germination against Cu stress. Further studies showed that NariS could promote amylase and esterase activities, reduce Cu-induced disturbance of plasma membrane integrity in the radicle tips, and sustain lower levels of malondialdehyde and H202 in germinating seeds. Furthermore, NariS pretreatment increased activities of superoxide dismutase and catalase and decreased that of lipoxygenase, but showed no significant effect on ascorbate peroxidase. Alternatively, NariS prevented uptake of Cu and promoted the accumulation of free amino acids in seeds exposed to Cu. In addition, a rapid accumulation of endogenous H2S in seeds was observed at the early stage of germination, and higher level of H2S in NaHS-pretreated seeds. These data indicated that H2S was involved in the mechanism of germinating seeds＇ responses to Cu stress.展开更多
文摘观察了7 种牧草种子在8 个NaCl浓度:0(0 Mpa),21(-0.1 Mpa),66(-0.3 Mpa),110(-0.5 Mpa),150(-0.70 Mpa),200(-0.9 Mpa),267(-1.2 Mpa),334(-1.95 Mpa),445(-2.603Mpa) m m ol/L下的发芽率及胚根和胚芽的生长,将盐胁迫下未萌发种子移入营养液中,观测它们在解除盐胁迫后发芽率、胚根和胚芽生长的恢复情况。结果表明,盐胁迫下,随盐浓度的增加,种子的发芽率呈下降趋势,但长穗偃麦草的发芽率几乎不受盐胁迫的影响,总体上它的胚芽和胚根长度随渗透势的降低而减少。21 m m ol/L的盐浓度对不同种的胚芽和胚根有不同的刺激作用。解除盐胁迫后,种子发芽率随原浓度的增加而增加,445 m m ol/L的高浓度对所有种的胚芽和胚根恢复生长最有利。因此,短时间,尤其是高浓度下的盐分锻炼,对种子的发芽及胚根和胚芽的生长有促进作用,但促进的幅度因种而异。生产实践中可用盐锻炼促进种子的发芽率,提高建植效果。
文摘Seed plants have evolved to maintain the dormancy of freshly matured seeds until the appropriate time for germination. Seed dormancy and germination are distinct physiological processes, and the transition from dormancy to germination is not only a critical developmental step in the life cycle of plants but is also impor- tant for agricultural production. These processes are precisely regulated by diverse endogenous hormones and environmental cues. Although ABA （abscisic acid） and GAs （gibberellins） are known to be the primary phytohormones that antagonistically regulate seed dormancy, recent findings demonstrate that another phytohormone, auxin, is also critical for inducing and maintaining seed dormancy, and therefore might act as a key protector of seed dormancy. In this review, we summarize our current understanding of the sophisticated molecular networks involving the critical roles of phytohormones in regulating seed dormancy and germination, in which AP2-domain-containing transcription factors play key roles. We also discuss the interactions （crosstalk） of diverse hormonal signals in seed dormancy and germination, focusing on the ABA/GA balance that constitutes the central node.
基金Supported by the Natural Science Foundation of Anhui Province (070411009)the Innovation Fund from Hefei University of Technology to undergraduate students (XS0637).
文摘With the enhancement of copper （Cu） stress, the germination percentage of wheat seeds decreased gradually. Pretreatment with sodium hydrosulfide （NariS）, hydrogen sulfide （H2S） donor alleviated the inhibitory effect of Cu stress in a dose- dependent manner; whereas little visible symptom was observed in germinating seeds and radicle tips cultured in NariS solutions. It was verified that H2S or HS- rather than other sulfur-containing components derived from NariS attribute to the potential role in promoting seed germination against Cu stress. Further studies showed that NariS could promote amylase and esterase activities, reduce Cu-induced disturbance of plasma membrane integrity in the radicle tips, and sustain lower levels of malondialdehyde and H202 in germinating seeds. Furthermore, NariS pretreatment increased activities of superoxide dismutase and catalase and decreased that of lipoxygenase, but showed no significant effect on ascorbate peroxidase. Alternatively, NariS prevented uptake of Cu and promoted the accumulation of free amino acids in seeds exposed to Cu. In addition, a rapid accumulation of endogenous H2S in seeds was observed at the early stage of germination, and higher level of H2S in NaHS-pretreated seeds. These data indicated that H2S was involved in the mechanism of germinating seeds＇ responses to Cu stress.
