蔺草开花因子及控制技术的探讨

蔺草开花对草茎品质有较大的影响。调查结果表明 ,品种、育秧方式、栽插时间和深度、草茎长度、温光条件以及割尖对蔺草的开花均有较大的影响。结合生产实践提出了进行品种选择 ,实施两段育秧 ,适时移栽 ,把握栽插深度等控制蔺草开花的技术措施。

Effects of Hormone Factors on the in vitro Culture Flowering Induction of Dendrobium officinate Kimura et Migo

[Objective]The aim was to select the suitable hormone factors for flowering induction in vitro culture of Dendrobium officinate Kimura et Migo.[Method]The test-tube plantlets from the stems of Dendrobium officinate Kimura et Migo were used as the experimental materials and MS medium as the basic medium.Comparative tests have been done between single-factor hormone treatments（different concentrations of PP333 or TDZ） and multi-factor hormone treatments（different combinations of PP333,TDZ,6-BA and NAA） to research the effects of hormone factors on the flowering induction of the plantlets.[Result]Among the single-factor hormone treatments,the suitable concentration and the rate of flower buds formation of PP333 treatment were 0.2 mg/L and 8.5%,the that of TDZ treatment were 0.06 mg/L and 15.5%;the effects of multi-factor hormone treatments on the flowering induction were ordered as follow：（PP333 ＋ 6-BA ＋ NAA ＋ TDZ）〉 （PP333 ＋ 6-BA ＋ NAA）〉 （PP333 ＋ 6-BA） and（PP333 ＋ NAA） ;the most suitable treatment was PP333 0.3 mg/L ＋ 6-BA 0.5 mg/L ＋ NAA 0.5 mg/L ＋ TDZ 0.06 mg/L,the rate of flower bud formation and the rate of the blossomed flower were respectly reached to 80.4% and 90.3%.[Conclusion]PP333 and TDZ showed the important effect on the flowering induction in vitro culture of Dendrobium officinate Kimura et Migo.The effect of TDZ was better than that of PP333.It is much more conducive to the flower bud formation,when using appropriate concentration of TDZ combined with other hormones properly.

A CIB1-LIKE transcription factor GmC IL10 from soybean positively regulates plant flowering

CRYPTOCHROME-INTERACTING basic helix-loop-helix 1(CIB1) is a well characterized transcriptional factor which promotes flowering through the physical interaction with the blue light receptor CRYPTOCHROME 2(CRY2) in Arabidopsis. However, the role of its counterpart in crop species remains largely unknown. Here, we describe the isolation and characterization of a CIB1 homolog gene, Glycine max CIB1-LIKE10(GmC IL10), from soybean genome. The m RNA expression of GmC IL10 in the unifoliate leaves shows a diunal rhythm in both long day(LD) and short day(SD) photoperiod, but it only oscillates with a circadian rhythm when the soybean is grown under LDs, indicating that the clock regulation of GmC IL10 transcription is LD photoperiod-dependent. Moreover, its m RNA expression varies in different tissue or organs, influenced by the develpomental stage, implying that GmC IL10 may be involved in the regulation of multiple developmental processes. Similar to CIB1, Gm CIL10 was evident to be a nuclei protein and ectopically expression of GmC IL10 in transgenic Arabidopsis accelerates flowering under both LDs and SDs, implying that CIBs dependent regulation of flowering time is an evolutionarily conserved mechanism in different plant species.

Interaction between temperature and photoperiod in regulation of flowering time in rice

Photoperiod and temperature are two pivotal regulatory factors of plant flowering. The floral transition of plants depends on accurate measurement of changes in photoperiod and temperature. The flowering time of rice （Oryza sativa） as a facultative short-day （SD） plant is delayed under long-day （LD） and/or low temperature conditions. To elucidate the regulatory functions of photoperiod and temperature on flowering time in rice, we systematically analyzed the expression and regulation of several key genes （Hd3a, RFT1, Ehdl, Ghd7, RID1/Ehd2/OsIdl, Se5） involved in the photoperiodic flowering regulatory pathway under different temperature and photoperiod treatments using a photoperiod-insensitive mutant and wild type plants. Our re- sults indicate that the Ehdl-Hd3a/RFT1 pathway is common to and conserved in both the photoperiodic and temperature flow- ering regulatory pathways. Expression of Ehdl, Hd3a and RFT1 is dramatically reduced at low temperature （23~C）, suggesting that suppression of Ehdl, Hd3a and RFT1 transcription is an essential cause of delayed flowering under low temperature con- dition. Under LD condition, Ghd7 mRNA levels are promoted at low temperature （23~C） compared with normal temperature condition （28℃）, suggesting low temperature and LD treatment have a synergistic role in the expression of Ghd7. Therefore, upregulation of Ghd7 might be a crucial cause of delayed flowering under low temperature condition. We also analyzed Hdl regulatory relationships in the photoperiodic flowering pathway, and found that Hdl can negatively regulate Ehdl transcription under LD condition. In addition, Hdl can also positively regulate Ghd7 transcription under LD condition, suggesting that the heading-date of rice under LD condition is also regulated by the Hdl-Ghd7-Ehdl-RFT1 pathway.