不同光照周期对蛋鸡高峰期血液生化指标的影响

选用20周龄海兰褐商品蛋鸡320只,随机分为8组,每组4个重复,每个重复10只鸡。试验处理采用渐增和骤增2种光增方式和4种光照周期,光周期设11L∶13D,13L∶11D,15L∶9D,17L∶7D 4个水平。结果表明,不同光增方式及光照时间对鸡体一些生化参数、代谢反应有一定影响,试验Ⅳ组血浆总蛋白、球蛋白含量和碱性磷酸酶活性最高。试验Ⅵ组,血钙、血磷含量最高(P<0.05)。同一光照时间,骤增光照处理组的血糖浓度低于缓增光照处理组,光照时间长,血糖浓度高。试验Ⅷ组谷丙转氨酶的活性、尿素氮含量最高。     

光周期对大豆叶片内源激素含量及其平衡的影响

选用生育期不同的３个品种，采用酶联免疫检测技术（ＥＬＩＳＡ），研究了开花前和开花后光周期处理对大豆叶片内源激素含量及其平衡状况的影响。结果表明，短日照与长日处理相比，脱落酸（ＡＢＡ）含量显著上升，赤霉素（ＧＡ１＋３）含量及ＧＡ／ＡＢＡ比例明显下降，细胞分裂素（ＤＨＺＲ，二氢玉米素核苷）有下降趋势，生长素（ＩＡＡ）的变化不大。短日下ＧＡ和ＩＡＡ含量负相关，ＧＡ与ＡＢＡ正相关，长日下ＩＡＡ与ＤＨＺＲ负     

Effect of food,light and host instar on the egg load of the synovigenic endoparasitoid <Emphasis Type="Italic">Venturia canescens</Emphasis> (Hymenoptera: Ichneumonidae)

Laboratory experiments investigated the effect of host instar, light and food on the number of mature eggs in ovaries (egg load) of the synovigenic parasitoid Venturia canescens (Grav.) (Hymenoptera: Ichneumonidae). The wasps that developed from third or fifth instar larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) were exposed to food (honey) or had no food, had access to water or not, and were reared at the photoperiod 16:8 h light:dark or in continuous darkness at 25 ± 1°C, and 60–70% relative humidity. After death, the parasitoids were dissected to remove the reproductive systems, and mature eggs in ovaries were counted. A three-way ANOVA for egg number with host instar, food and light as factors revealed that egg load varied significantly. In addition, some interactions among the three factors were also found to be significant. The maximum average number (215.80 ± 8.51) of mature eggs was found when the parasitoids developed from third instar larvae, were exposed to continuous darkness and fed with honey. In conclusion, host instar, food supplement and photoperiod could have potential for improving biological control efficacy in stores. However, further studies determining the effect of these factors on egg laying behavior and fecundity should be done.     

Seed number responses to extended photoperiod and shading during reproductive stages in indeterminate soybean

The number of seeds per unit land area, the major yield component in soybean (Glycine max (L.) Merrill) is largely determined after the beginning of flowering, particularly from R3 to R6. Environmental factors increasing crop growth rate (e.g. radiation) or extending the duration of the reproductive phases (e.g. photoperiod) increase the number of seeds. We aimed to compare the mechanisms by which photoperiod and radiation affect the definition of final seed number during the critical period of R3–R6. Two field experiments were conducted with indeterminate soybeans at intermediate maturity group. All plots in each experiment were grown under natural conditions until the beginning-pod stage (R3); and from then onwards different treatments were imposed. Treatments consisted of the factorial combination of two levels of radiation (natural or shading) and two photoperiod regimes (natural or extended). Extended photoperiod increased the duration of reproductive phases, the number of nodes and the number of pods produced on the nodes that flowered during or after the applications of the treatments. Shading had negligible effects on development and node number, but reduced crop growth rate and also reduced the number of pods produced on most nodes of the plants. The number of seeds was positively related to the crop growth rate during R3–R6, but photoperiod increased the number of seeds produced per unit of crop growth rate, due to the lengthening of the phase. The number of seeds was therefore even better related to accumulated growth during R3–R6, irrespective of the factor that increased the accumulated biomass (higher daily radiation or longer duration of the phase) suggesting that long photoperiods increased the number of pods and seeds established per unit land area, mainly through increasing the total resource availability during a phase that is critical for the determination of seed number in soybean. However, photoperiod regulation involved additional changes in the development, evidenced by changes in the pod distribution pattern within the canopy.     

光周期对秋眠型苜蓿Vernal SOD、POD活性的影响

研究了16h(long day,LD)、12h(middle day,MD)8h(short day,SD)三个不同的光照时间对秋眠型苜蓿Vernal超氧化物歧化酶(Superoxide Dismutase,SOD)和过氧化物酶(Peroxidase,POD)活性的影响,为进一步研究苜蓿秋眠性的生理机制奠定基础.结果表明:秋眠型苜蓿Vernal SOD和POD的活性呈现8 h光照处理最高,12h次之,16h最低的趋势;同一光周期条件下,SOD、POD的活性随着生长时间的延长而升高,提示SOD、POD的活性与苜蓿的光周期有关,短日照可提高SOD、POD的活性.     

温度和光周期与丝瓜花性分化及其生理的研究 Ⅲ 丝瓜花性分化与核酸、蛋白质及内源ABA的关系

应用人工气候室研究了不同温度和光周期组合处理,以探讨对丝瓜(Luffaacutangula Roxb.)花性分化与核酸、蛋白质及内源ABA的关系。试验表明,低温和短日条件,可以促进总核酸、RNA、DNA和蛋白质的合成和积累,为丝瓜雌性分化提供良好的物质基础。处理期间ABA含量前后变化不大。F_(ABA)/B_(ABA)比小,F_(ABA)含量降低时,丝瓜雌性分化较强。最后,对温度和光周期影响丝瓜花性分化的生理基础进行了探讨。     

利用永久F2群体在不同光周期环境下定位玉米株高QTL

为了研究热带玉米株高的遗传机制, 利用温热组合黄早四×CML288衍生的重组自交系群体构建了一个包含278个组合的永久F₂群体, 分别在海南三亚、河南郑州和洛阳、北京昌平和顺义等5个地点3种光周期环境中进行株高鉴定。利用复合区间作图法在3种光周期环境下共定位到12个不同的玉米株高QTL。位于第1染色体上的qPH1-2和位于第4染色体上的QTL qPH4在3个环境中同时被检测到, 表明这2个QTL在不同日照环境下均能稳定表达。位于第3染色体上的qPH3在短日照环境下能解释株高遗传变异的32.13%, 而在2个长日照环境下并未被检测到, 表明此QTL是短日照环境下特异表达的主效QTL。第10染色体上QTL qPH10-1分别解释2个长日照环境中株高遗传变异的25.39%和39.58%, 是长日照环境下特异表达的主效株高QTL。     

Phenology and growth dynamics in Mediterranean evergreen oaks: Effects of environmental conditions and water relations

Budburst date and shoot elongation were measured in two mature Mediterranean evergreen oaks (Quercus suber and Quercus ilex) and their relationships with meteorological and tree water status (predawn leaf water potential) data were analysed. Experimental work took place at two sites: Mitra 2 - Southern Portugal (2002-2003) and Lezirias - Central Portugal (2007-2010). Quercus suber phenology was studied at both sites whereas Q. ilex was only studied at Mitra 2. Quercus suber budburst date occurred at a photoperiod around 13.8 h (± 0.26) - late April/early May - and was highly related to the average daily temperature in the period 25 March - budburst date (ca. 1.5 months prior to budburst), irrespective of site location. In that period, budburst date was much more dependent on average maximum than average minimum daily temperature. Base temperature and thermal time for Q. suber were estimated as 6.2 °C (within the reported literature values) and 323 degree-days, respectively. Q. ilex budburst occurred about 6 weeks earlier than in Q. suber (photoperiod: 12.3 h (±0.3)). Relationships of Q. ilex budburst date and temperature were not studied since only 2 years of data were available for this species. Q. suber shoot elongation underlying mechanisms were quite different in the two sites. At Mitra 2 (Q. suber and Q. ilex), there was a considerable tree water stress during the dry season which restricted shoot elongation. Shoot growth was resumed later in the wet autumn when tree water status recovered again. At the Lezirias site Q. suber water status was not restrictive. Therefore, shoot elongation was mainly dependent on nutrient availability in top soil, as suggested by the strong and positive relationships between annual shoot growth and long-term cumulative rainfall (2-4 months) and short-term average temperature (1 month) prior to budburst. Annual shoot elongation at this well-watered site was higher than in Mitra 2, and variability of growth between trees was enhanced after warm, wet springs when shoot elongation was higher. Results obtained are relevant to the carbon balance, productivity and management of evergreen Mediterranean oak woodlands, particularly under the foreseen climate change scenarios.     

Studies on the Heredity of the Traits Related to the Photoperiod-Sensitive Phenomenon Among the Temperate × Tropical Crosses in Maize

The genetic study of characters concerning photoperiod sensitivity of the growth and development stages, plant and ear height was carried out from 5 temperate tropical combinations by using P1, P2, F1,F2, BC1, BC2 generations mean analysis. The results showed that the square sums of additive, of dominance and of epistatic gene effects contributed to total genetic variance were 11.3 -53.6 %, 36.0 -78.6 % and 5.5 -27.0% respectively for five traits of the insensitive× insensitive combination to photoperiod, which suggested dominance gene effect was the most important among various gene effects. In insensitive × sensitive combination to photoperiod, the square sums of additive gene effect with 66.9 - 84.5 %, of dominance gene effect with 11.6 -30.7% and of epistatic gene effect with 1.4 -5.2% were found for five tested traits, which showed additive gene effect held a dominant position, and dominance and epistatic gene effects were reduced compared with insensitive× insensitive combination. The differences existed among different insensitive × sensitive combinations. The proportion of the genetic component among the insensitive × sensitive crossbreed offspring in the temperate zone had a certain dosage effect on fading photoperiod sensitivity reaction. The sensitivity of BC1, with 25 % of the tropical genetic component, is extremely weak, but with high application value.     

光敏核不育水稻的光温反应研究——Ⅱ.人工控制条件下粳型光敏不育系的育性鉴定

在人工控制条件下研究了光照时间和温度对农垦58S及以此为基因源转育的其他粳型光敏不育系育性的影响。结果表明,供试粳型光敏不育系的育性受光照时间和温度的双重影响,在15.0h光长与29.6℃平均温度(最高与最低温度分别为33.0℃与28.0℃)的长光照高温条件下,自交结实率为0或接近于0;在12.0h光长与23.6℃平均温度(27.0/22.0℃)的短光照低温条件下,自交结实率较高;在长光低温(15.0h/23.6℃)和短光高温(12.0h/29.6℃)下,育性出现不同程度的转变。不同材料的育性对光温反应存在着差异,提示遗传背景对育性表达可能有重要作用。本研究结果有助于对自然条件下光敏不育系夏季制种纯度不高而秋季警种产量又较低的现象在理论上给予合理的解释。