价异构

It was also found that the chromosomes paired well and formed a rod heteromorphic bivalent in the hybrid F1[73(36)9-1×CSDT 1BL]. Whereas 73(36)9-1 produced mainly configuration of 20''+1'+t' when test-crossed with CSDT 1BS. It showed that the translocation occurred on chromosome 1B short arm, and this segment came from rye chromosome 1RL. In the present paper we discussed also the way in which the translocation might be caused, and concluded that it was formed through reunion of two kind telocentrica (1BL and 1RL) after simultaneous misdivision of two univalent chromosomes (a wheat chromosome 1B, and a rye 1R).

同时还发现，73（36）9-1和"中国春"双端体的1BL能很好地配对并形成一个棒状的异形二价体，而它和CSDT 1BS的染色体则主要产生20+1′+t′的构型，从而证明易位发生的可能途径，推断是由于在F1花粉母细胞中的两个单价体（一个是小麦染色体1B，一个是黑麦染色体1R）同时进行错分裂之后产生的两种端着丝点染色体（1BL和1RL）重新并合形成的，因而冬小麦73（36）9-1可能是一个自发产生的易位系。

Fromthese facts,It could be deduced that 8 to 14 pairs of chromosomes possessed a certaindegree of hetorology,which was directly groved to be hybrid origin of P.tomentosaaccording to the good chromosome homology and fertility of P.bolleana and thehybrids of P.tomentosa×P.bolleana,it could be further deduced that the original parentsof P.tomentosa involved probably P.bolleana or P.alba.

从终变期、中期I的染色体构型看，有数目不等的联会程度较差的单价体和棒状二价体出现，在后期I，甚至末期I亦可见到含落后染色体分裂相的细胞，由此推断可能有8~14对染色体表现出一定程度的异源性，鉴于新疆杨以及毛白杨与新疆杨杂交产生的杂种毛新杨的染色体同源性较强、育性较好等现象，进一步推断毛白杨起源亲本可能包括新疆杨或银白杨。

Thus, the meiotic chromosome cofigurations showed that the tetraploids and hexaploids in C.reticulata allopolyploids, and the appearance of a few tetravalents in some populations might indicatehomology of chromosomes in different genomes to some extent.

根据减数分裂的构型，我们认为，四倍体和六倍体分别为异源四倍体和异源六倍体，少数四价体的存在表明染色体有部分同源性。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。