对温、热带玉米杂交后代RIL的评价及其光周期敏感性研究

分析了温带玉米自交系黄早四、热带玉米自交系CML288及其衍生的F6重组家系(RIL)在中纬度和低纬度生态环境下的生育性状,对来自于同一亲本材料的F6重组家系和F3家系做了比较分析,研究了热带、亚热带玉米光周期敏感性及其相关性状的遗传特点。结果表明:在郑州长日照和三亚短日照条件下,F6重组家系的抽雄期、散粉期、吐丝期、株高、穗位高和叶片数等光周期敏感指数均表现出数量遗传特点。F6重组家系的平均值接近双亲平均值,有一定数量的双向超亲家系;F3家系通过随机选择连续自交到F6代后,生育期稍有提前,植株和穗位降低,变异范围扩大。因此,F6重组家系群体可以用于进行QTL定位分析。长、短日照两种条件下F6重组家系光周期敏感相关性状与F3家系的相关系数极显著,F6重组家系各性状变异范围与F3家系相比均有明显扩大的趋势。说明随着世代数的增加,杂合基因型家系在群体中的比例逐步减小,显性、隐性纯合基因型的家系所占的比例越来越大。     

Effects of continuous light and short-day photoperiod on smolting, seawater survival and growth in Atlantic salmon (Salmo salar)

Duplicate groups of 1-year-old Atlantic salmon were exposed to 5–7 weeks of short days (LD 8.15:15.45) with artificial light, followed by a period of continuous light (LL) for 3 months (A), 2 months (B) or 1 month (C) before transfer to sea cages. Duplicate groups were also exposed to a 2-week period of LD 8.15:15.45, followed by a period of continuous light for 2 months (D). Comparisons were made with fish that were reared under natural light conditions from October onwards (F) and continuous light (E) only. Fish from all groups were transferred to sea cages on 9 June and their survival and growth were monitored until 31 October. There was a significant (P < 0.001) interaction between light regime and time for all smolt characters measured. Development of smolt colouration, decrease in condition factor, increases in gill Na-K-ATPase activity and the ability to regulate plasma Na⁺ after 24 h in full-strength sea water, indicated that the fish in groups A, B and C completed smoltification 6–8 weeks after the end of the short-day periods. No decrease in the condition factor was recorded for fish in groups D and E. The mortality was 40% for group A and 34% for group B, and 15% or less for the other groups. Groups A and B had probably lost some of the smolt characters by the time of seawater transfer. The specific growth rate in sea water was 1.5% for group F and for the survivors of groups A and B, 1.4% for group C and 1.2% for groups D and E. In conclusion, a short-day regime of 5–7 weeks, followed by continuous artificial light, caused smolt-related changes similar to those found in outdoor-reared fish, whereas this was not so for fish exposed to either a short-day period of only 2 weeks or to continuous artificial light.     

玉米类LFY基因的克隆及其在不同光周期条件下的表达

采用每天9 h和15 h两种光照条件对热带玉米自交系CML288和温带玉米自交系黄早四进行处理。以玉米茎尖为材料，采用RT-PCR方法，分离到1个1 265 bp的全长cDNA克隆，序列比较表明其为拟南芥LFY基因的同源基因，命名为类LFY（基因登录号为DQ343237）。类LFY与同源基因zfl2、RFL、LFY和FLO的同源性依次为93%、84%、57%和57%。它的DNA序列和推论的蛋白质序列与zfl1同源性最高，其编码的蛋白质与zfl1相比在第28、29和160位分别少1个丙氨酸、脯氨酸和苏氨酸，在188位置多1个甲硫氨酸。该基因在2个供试自交系茎尖中长日照条件下不同生长时期持续表达，短日照条件下生长早期和后期不表达，其功能有待进一步研究。     

The components of lucerne (Medicago sativa) leaf area index respond to temperature and photoperiod in a temperate environment

Irrigated crops of ‘Grasslands Kaituna’ lucerne were grown for 5 years in a temperate climate at Lincoln University, Canterbury, New Zealand (43°38′S, 172°28′E). From these the response of the components of leaf area index (LAI) to environmental factors was determined. A broken stick temperature threshold with a base temperature (T_b) of 1 °C at air temperatures (T_a) <15 °C and a T_b = 5 °C for T_a ≥ 15 was required to accumulate thermal time (Tt). Using this, the appearance of nodes on the main-stem (phyllochron) was constant in Tt within a re-growth cycle (30–42 days). The phyllochron was 37 ± 7 °Cd but declined from 60 to 37 °Cd as photoperiod decreased from 15.7 to 11.4 h. Branching began at the appearance of the fifth main-stem node with 2.5 secondary nodes produced per main-stem node in spring re-growth cycles but only 1.7 produced in summer. Leaf senescence increased from 0.3 to 1.08 leaves per main-stem node after the appearance of the ninth node. Spring re-growth cycles had a mean individual leaf area of 170 mm² compared with 400 mm² for summer re-growth cycles. These results demonstrate systematic variation in LAI components and suggest they need to be considered separately in response to environmental factors to provide a quantitative framework for crop simulation analyses of lucerne canopy development.     

光周期基因在我国小麦品种中的多态性分布

为了明确光周期基因显隐性组成在我国小麦品种中的分布情况,利用小麦光周期基因Ppd-A1、Ppd-B1和Ppd-D1的STS分子标记,对我国180份小麦品种进行分子标记检测。结果显示,所有供试材料在B1位点均检测为隐性Ppd-B1b。在A1位点,仅有扬麦11品种检测为显性Ppd-A1a(0.6%),其余检测材料均为隐性Ppd-A1b;在D1位点,有5份材料检测为隐性,其余175份材料检测均为显性Ppd-D1a(97.2%)。对所有材料进行基因型统计分析,发现我国品种主要存在Ppd-A1b/Ppd-B1b/Ppd-D1b、Ppd-A1b/Ppd-B1b/Ppd-D1a和Ppd-A1a/Ppd-B1b/Ppd-D1a几种基因型。研究结果表明,我国小麦品种的光周期不敏感特性主要是Ppd-D1位点的变异,在Ppd-A1、Ppd-B1位点的变异较少。     

HPGMR衍生的籼型两用核不育系的光(温)敏不育基因的等位性研究

1990～1991年观察分析了以 HPGMR(Hubei Photoperiodsensitive Genic Male-sterileRice)农垦58S 转育的8个籼型光(温)敏核不育系及其相互杂交 F_1,以及部分组合 F_2,BC_1F_1在武汉自然长光照下或遮光短日照下的育性表现。结果表明,籼型光敏核不育系 W7415S、32001S、3403S、T09S、8902S 和8912S 的光敏不育基因座位相同,推论其光敏不育基因均来源于农垦58S,并且相互间存在修饰基因的差异;而温敏型核不育系 W6154S 与光敏型核不育系 W7415S 等的不育基因座位不相同,推测农垦58S 的光敏不育基因可能没有导入 W6154S 中去;温敏型核不育系 W6154S 和温敏型核不育系8801S 的不育基因座位也不相同,这两个温敏核不育系可能具有不同的遗传基础。     

光(温)敏核不育水稻的育性和开花习性研究

在合肥地区自然条件下,对7个光(温)敏核不育系的育性稳定性和育性转换特性及开花习性进行了研究。结果表明:粳型7001S、N5088S和31111S不育性稳定,不育期花粉败育率、自交结实率分别为99.82—99.96%、0.00—0.03%,育性转换明显,转换期自9月5—6日先后开始,可育期花粉败育率27.82—41.72%,自交结实率20.92—44.00%,作为两系杂交稻的母本应用可行。粳型N5047S、籼型W7415S基本具有与上述3个粳型核不育系相似的育性稳定性和育性转换特性,用作母本基本可行。籼型W6154S、8801S不育期因花粉母细胞减数分裂期低温,出现不同程度不同次数的育性波动,应用风险大。粳型7001S、N5088S、31111S和W6154S开花完全(颖花开花率较高),张颖时间较长或中,花时高峰早且集中,或花时分散但午前花率较高,利于制种,N5047S、W7415S、8801S开花率低,盛花时迟或颖花张颖时间短,制种困难。     

光照和褪黑激素对内蒙古绒山羊氮分配和产绒性能的影响

【目的】研究日粮氮营养在绒山羊体内的分配机理，调控氮营养在绒山羊体内的分配，提高舍饲绒山羊的经济效益，减少放牧，保护草原生态。【方法】用缩短光照和埋植褪黑激素的方法调控氮营养向绒毛方向分配。【结果】光照时间和埋植褪黑激素对绒山羊体内相关激素有显著影响，通过相关激素的变化调节绒山羊体内体氮和毛绒氮的分配比例。短光照和埋植褪黑激素使血液中褪黑激素含量升高，毛绒氮分配比例增加而体氮分配比例减少，促进绒毛生长，试验期内绒山羊的产绒量平均增加338.83±72 g，提高73.8%。绒毛各项品质指标均达到纺织工业标准的要求。【结论】绒山羊的绒毛生长可以通过改变光照和埋植褪黑激素进行调控，在非生绒季节诱导产绒，在生产实践中有巨大的推广价值。     

开花后光照长度对大豆化学品质的影响

 在人工控制条件下研究了开花后光照长度对大豆化学品质的影响及开花后各发育阶段长度与大豆化学品质性状的相关性。试验结果表明，光照长度对大豆化学品质有很大影响。光照长度的作用不仅涉及光合时间，而且与光周期本身的机制有关。长光照下大豆蛋白质含量下降，脂肪含量上升，棕榈酸和油酸占脂肪的比例下降，亚油酸和亚麻酸的比例有所升高，硬脂酸含量存在处理间的显著差异，但与光照长度的关系复杂。开花期、结荚期和鼓粒期的光照处理均对大豆化学品质有影响。相关分析表明，大豆化学品质性状与花荚期和鼓粒期长度关系密切，较长的开花后阶段有利于脂肪含量和亚油酸比例的提高。品种遗传特性对大豆化学品质性状的影响大于光照长度的作用。     

Endocrine growth regulation of adult Atlantic salmon in seawater: The effects of light regime on plasma growth hormone, insulin-like growth factor-I, and insulin levels

Plasma growth hormone (GH), insulin-like growth factor-I (IGF-I), and insulin were measured in two groups of Salmo salar L. during a one-year study. The fish were reared under either a simulated natural photoperiod (SNP) from January to December or a regime of continuous light from January to June, followed by SNP until December (LL/SNP). Plasma GH levels during spring were low, and lower in the LL/SNP fish (< 0.9 ng ml^− 1) than in the SNP fish (> 1.9 ng ml^− 1), although the LL/SNP grew better (0.8% per day) than the SNP fish (0.5% per day). Plasma IGF-I levels increased transiently from January (64.7 ng ml^− 1) to maximum in late September in the LL/SNP (85.8 ng ml^− 1) and in November in the SNP group (87.3 ng ml^− 1). The ratio GH:IGF-I was lower in the LL/SNP group during spring when this group grew better than the SNP group.