Various individual organs (tepal, flower bud, inflorescence branch, inflorescence, adult vegetative bud and juvenile vegetative bud) were directly regenerated respectively by callus in Dracaena fragrans cv. massangean...Various individual organs (tepal, flower bud, inflorescence branch, inflorescence, adult vegetative bud and juvenile vegetative bud) were directly regenerated respectively by callus in Dracaena fragrans cv. massangeana Hort. During the regeneration of these individual organs some regularity phenomena were observed. Firstly, the kind range of the individual organs, which are directly regenerated in vitro, is in close relationship to the differentiated stages of the organs used for explant excision during plant ontogeny. The explants excised from the epigeous organ that is differentiated at some stage (stage A) during plant ontogeny must be able to separately regenerate all of those individual epigeous organs: ones differentiated slightly later than the stage A, ones differentiated at the stage A and all ones differentiated earlier than the stage A. Secondly, within this range which kind of organ is regenerated depends on the exogenous auxin concentrations in medium. With the gradual increase of 2,4-D concentration from 0.005 mg/L to 0.5 mg/L, the kinds of regenerated organs will change by the order as follows: vegetative bud, inflorescence, inflorescence branch, flower bud, tepal. These regularities will be able to be used for inducing the direct regeneration of a given epigeous organ in angiosperms.展开更多
离体条件下风信子(Hyacinthus oricntalis L.) 再生雄蕊的小孢子发生和雄配子体发育的细胞学观察表明:从四分体到二细胞花粉,二者的细胞学特点基本一致。发育到成熟花粉时,再生雄蕊的成熟花粉是三细胞的,自然情况下是二细胞的。表明了...离体条件下风信子(Hyacinthus oricntalis L.) 再生雄蕊的小孢子发生和雄配子体发育的细胞学观察表明:从四分体到二细胞花粉,二者的细胞学特点基本一致。发育到成熟花粉时,再生雄蕊的成熟花粉是三细胞的,自然情况下是二细胞的。表明了两者在生殖细胞分裂完成的时间和完成时在细胞中所处的位置等方面都存在明显的差异。对这种差异产生的原因及是否会对精细胞产生影响等方面进行了讨论。展开更多
离体条件下风信子(Hyacinthus orientalis L.)再生胚珠的形态发生及大孢子发生和胚囊发育的细胞学研究表明:再生胚珠具有正常的珠被、珠心和珠柄的分化过程,但其形状与自然情况下的明显不同,绝大部分再生胚珠是直生型和半倒生型,与自然...离体条件下风信子(Hyacinthus orientalis L.)再生胚珠的形态发生及大孢子发生和胚囊发育的细胞学研究表明:再生胚珠具有正常的珠被、珠心和珠柄的分化过程,但其形状与自然情况下的明显不同,绝大部分再生胚珠是直生型和半倒生型,与自然情况下相同的倒生型胚珠极少;胚珠的大孢子发生和胚囊的发育具有正常的细胞学过程。最后可形成1个卵细胞,2个助细胞,1个中央细胞和3个反足细胞的8核蓼型胚囊。结果表明,处于完全孤立状态下的再生胚珠,自分化启动以后即能按预先确定的发育程序完成大孢子发生和胚囊发育的复杂过程。由此推测,完成这个复杂过程是胚珠自控的,它不需要来自花芽或植株的任何信息。展开更多
文摘Various individual organs (tepal, flower bud, inflorescence branch, inflorescence, adult vegetative bud and juvenile vegetative bud) were directly regenerated respectively by callus in Dracaena fragrans cv. massangeana Hort. During the regeneration of these individual organs some regularity phenomena were observed. Firstly, the kind range of the individual organs, which are directly regenerated in vitro, is in close relationship to the differentiated stages of the organs used for explant excision during plant ontogeny. The explants excised from the epigeous organ that is differentiated at some stage (stage A) during plant ontogeny must be able to separately regenerate all of those individual epigeous organs: ones differentiated slightly later than the stage A, ones differentiated at the stage A and all ones differentiated earlier than the stage A. Secondly, within this range which kind of organ is regenerated depends on the exogenous auxin concentrations in medium. With the gradual increase of 2,4-D concentration from 0.005 mg/L to 0.5 mg/L, the kinds of regenerated organs will change by the order as follows: vegetative bud, inflorescence, inflorescence branch, flower bud, tepal. These regularities will be able to be used for inducing the direct regeneration of a given epigeous organ in angiosperms.
文摘离体条件下风信子(Hyacinthus oricntalis L.) 再生雄蕊的小孢子发生和雄配子体发育的细胞学观察表明:从四分体到二细胞花粉,二者的细胞学特点基本一致。发育到成熟花粉时,再生雄蕊的成熟花粉是三细胞的,自然情况下是二细胞的。表明了两者在生殖细胞分裂完成的时间和完成时在细胞中所处的位置等方面都存在明显的差异。对这种差异产生的原因及是否会对精细胞产生影响等方面进行了讨论。
文摘离体条件下风信子(Hyacinthus orientalis L.)再生胚珠的形态发生及大孢子发生和胚囊发育的细胞学研究表明:再生胚珠具有正常的珠被、珠心和珠柄的分化过程,但其形状与自然情况下的明显不同,绝大部分再生胚珠是直生型和半倒生型,与自然情况下相同的倒生型胚珠极少;胚珠的大孢子发生和胚囊的发育具有正常的细胞学过程。最后可形成1个卵细胞,2个助细胞,1个中央细胞和3个反足细胞的8核蓼型胚囊。结果表明,处于完全孤立状态下的再生胚珠,自分化启动以后即能按预先确定的发育程序完成大孢子发生和胚囊发育的复杂过程。由此推测,完成这个复杂过程是胚珠自控的,它不需要来自花芽或植株的任何信息。
