低温层积对纳罗克非洲狗尾草种子内源激素的影响

The Effect of Cold Stratification to Germinative Rate and Endogenous Hormone of Setaria Sphacelata cv.“Narok”

纳罗克非洲狗尾草(Setaria sphacelata cv."Narok")为热带、亚热带优良禾草之一,但其种子的休眠程度高,发芽率低。以层积0d为对照,对1年龄纳罗克非洲狗尾草生产的种子进行0～120d的低温层积处理,结果表明:随着层积时间的延长,种子的发芽率表现出先快速增加然后缓慢下降的趋势,层积30d发芽率达到最大值,为75%,是对照的2.08倍(P<0.01),休眠已解除;GA_3、IAA、ZR的含量先升高后降低;ABA的含量则表现为先下降后回升又下降的趋势;GA_3/ABA的比例在层积0～15d快速升高,15～30d保持较高水平,30d后虽有起伏但有降低(P<0.05)。GA_3/ABA的比例0～15d快速升高,15d后逐渐下降。IAA/ABA、(GA_3+IAA)/ABA比例0～15d快速升高(P<0.05),15～60d下降,之后略有回升。ZR/ABA比例0～30d快速升高(P<0.05),30～60d下降,60d后又开始升高(P<0.05)。相对较高的GA_3/ABA、IAA/ABA、ZR/ABA、(GA_3+IAA)/ABA比例是种子休眠解除的重要体现。

Setaria sphacelata cv.＂Narok＂ is one of excellent tropical grass forages.But the forage seed dormancy degree is high,the germination rate is low.The cold stratification after 0 day seed as the control,for planting 1st years ＂ Narok＂ seeds of cold stratification treatment and observation product seeds occurred in the process of endogenous hormone changes.The content of IAA、 GA_3、ZR first increased and then decreased with time,and ABA content decreased with time after the first decline and fall;GA3/ABA ratio were expressed as 0～ 15 days rapid increase（P0.05）,15 d and 30 d was maintained in high level,and decreased gradually after 30 days.IAA/ABA、（ GA3＋IAA） /ABA ratio were expressed as 0 ～ 15 days（ P〈 0.05）,15 ～ 60 d decreased,then rose slightly.ZR/ABA ratio were expressed as 0～ 30 days（P〈0.05）,30 ～ 60 d decreased and 60 d began to increase..It explained that the relatively high GA_3/ABA、 IAA/ABA、 ZR/ABA、（GA3＋IAA） /ABA ratio were an important manifestation of seed dormancy release.