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排序方式: 共有602条查询结果,搜索用时 31 毫秒
1.
光照和褪黑激素对内蒙古绒山羊氮分配的影响 总被引:1,自引:0,他引:1
从氮分配的角度研究了光照和褪黑激素对内蒙古白绒山羊营养分配的影响。结果表明:光照时间和埋植褪黑激素显著影响绒山羊体内氮物质分配,短光照或埋植褪黑激素显著提高绒山羊血液中的褪黑激素水平,并使其他相关激素如催乳素(PRL)、胰岛素(INS)、类胰岛素生长因子-I(IGF-I)、瘦素(LEP)的含量发生显著变化,结果使毛绒氮的沉积增加,体氮的沉积减少。短光照条件下毛绒氮和体氮的沉积分别为33.7%±0.64%和66.3%±0.64%;而长光照条件下则减少毛绒氮的分配量,增加体氮分配量,毛绒氮和体氮的沉积分别为23.6%±0.46%和76.4%±0.46%。短光照和褪黑激素之间有强烈的互作效应,短光照埋植褪黑激素组毛绒氮和体氮的分配比例分别为36.1%±0.79%和63.9%±0.79%。试验期绒山羊的产绒量平均增加(338.83±72)g,比普通绒山羊提高73.86%,新生羊绒的品质符合纺织工业标准的要求。 相似文献
2.
Lina Maria Correa Ricardo D. Moreno José Luis Riveros 《Reproduction in domestic animals》2021,56(4):680-683
The present study examined the effects of different photoperiods and melatonin treatment on plasma prolactin concentrations in guanacos, a South American camelid, in captivity. Fourteen adult female guanacos, not gestating or lactating and isolated from males, were studied. The control group was exposed to natural daylight, during short days (N = 7, 10L:14D) and long days (N = 7, 16L:8D). The treatment group (N = 7, 10L:14D) received melatonin implants every 23 days for 6 weeks during long days. Blood samples were taken at intervals of 1 week for 3 weeks, starting the third week of treatment. Prolactin concentrations were measured using competitive ELISA. Plasma concentrations of prolactin in non-lactating female guanacos have seasonal changes, with a higher concentration (p < .001) in short days (3.50 ± 2.24 ng/ml) than long days (1.10 ± 0.91 ng/ml). Melatonin treatment significantly decreases (p < .05) plasma concentrations of prolactin on the 21st day after the treatment. These findings are the first report of an endogenous circannual rhythm of plasma prolactin concentration and the action of melatonin treatment on prolactin secretion in this wild camelid. 相似文献
3.
粳型光敏核不育系与常规粳稻杂交后代育性的遗传分析 总被引:6,自引:0,他引:6
在分析粳型光敏核不育系与粳稻品种杂交组合F_3及以后世代部分株系的育性和基因型的基础上,对分离世代各种主基因型的育性及频率分布进行了估计,验证了根据F_1、F_2和BF_1代作出的水稻光敏核不育性及其育性恢复的遗传涉及核内2对独立的主基因的遗传结论。由F_6以上高世代株系中测选出对农垦58s恢复效应有明显差异的两种纯合单显性可育株系,获得了存在两个不同恢复基因的遗传证据。 相似文献
4.
早籼型水稻温敏核不育系M103S的选育与光温反应特性 总被引:3,自引:2,他引:3
以温敏核不育水稻安农S—1为母本,以常规高产早籼稻品系92153为父本进行杂交,通过低温选择和人工气候箱鉴定,育成了育性转换临界温度23—24℃的早籼型温敏核不育系M103S。光周期长于12.5h,日平均温度高于24℃,可以用于制种,日平均温度低于23℃,可以用于繁殖。光周期长于13.5h,日平均温度高于23℃,可以用于制种。自然条件下不育起点温度为日均温23—24℃,耐低温期为3—4d。敏感期为抽穗前的7—14d。播始历期为53—79d,主茎叶片数10.0—12.6片。从播种到始穗的活动积温和有效积温,分别为1493.8—1766.3℃和733.4—1058.3℃。不育期的株高63.6—77.5cm,平均72.0cm,单株有效穗6.4—12.0个,平均9.3个,穗长20.9—22.7cm,平均21.2cm,每穗颖花数112.1—137.3朵,平均122.3朵。可育期株高65.7cm,单株有效穗7.2个,穗长17.2cm,每穗总粒数114.1粒,结实率47.23%,千粒重31.34g。以M103S为母本,与100多个早籼品种进行测配,杂种表现生育期早、穗大、粒多、千粒重高。 相似文献
5.
不同光增方式和周期对蛋鸡蛋品质和血液生化指标的影响 总被引:1,自引:0,他引:1
研究光增方式和光照周期对蛋鸡蛋品质和血液生化指标的影响。将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。试验光照周期采用渐增和骤增2种,光周期设11L∶13D、13L∶11D、15L∶9D、17L∶7D4个水平。结果表明:①不同光增方式对蛋形指数和哈氏单位有显著影响(P<0.05),以渐增条件下较好。不同光增方式对血液生化指标没有显著影响(P>0.05)。②不同光照周期对蛋黄颜色有显著影响(P<0.05),以15L∶9D处理组蛋黄颜色最好。不同光照周期对血液生化指标有一定影响,以13L∶11D处理组较好。 相似文献
6.
R. Keeve G. H. J. Krüger H. L. Loubser J. A. M. Van Der Mey 《Journal of Agronomy and Crop Science》1999,183(4):217-223
An experiment to determine the effect of temperature and photoperiod on Lupinus albus under controlled environmental conditions was carried out, using the three Lupinus albus genotypes 'Tifwhite', 'Esta' and 'Kiev', and three temperature (10/20, 18/28 and 20 °C continuously) and two photoperiod (8 and 16 h daylength) regimes, in all combinations. Half of the seeds were vernalized for 21 days at 4 °C to alleviate the obligate vernalization requirement of Tifwhite. Although Esta and Kiev do not have obligate vernalization requirements, they were influenced by this vernalization period. Observations included the duration of the period from planting to seedling emergence, the duration of the period from planting to the beginning of flowering and the duration of flowering. The vernalization treatment accelerated plant development in all genotypes. The period from planting to emergence was shorter under the higher temperature regime. For all genotypes, the period from planting to flowering was shorter under the longer photoperiod, the same trend as would be expected for long-day plants. Duration of flowering periods were, in contrast to pre-flowering periods, shorter for all genotypes at cooler temperatures. The results of this study confirm that photoperiod does contribute to the growth period from planting to flowering in L. albus and that this species does behave as a long-day plant. 相似文献
7.
《Journal of Crop Improvement》2013,27(1-2):77-112
Summary Tree species adapted to the climatic conditions of the northern boreal and subarctic vegetation zones have a capacity to develop a very high level of frost hardiness, even to survive the temperature of liquid nitrogen in midwinter. Proper timing of hardening, as well as of dehardening, is crucial for winter survival of these species. In northern tree species, cessation of apical elongation growth and bud set is a prerequisite for developmental and metabolic processes leading to hardening, and this chain of events is induced by photoperiod. The northern tree species are closely adapted to the local light climate and display photoperiodic ecotypes. The critical photoperiod is under genetic control and increases with increasing latitude of origin of the eco-type. The photoperiod is probably perceived by the phytochrome system, but the role of other pigment systems, like cryptochrome, has not been studied in woody plants. Phytochrome genes have been cloned from both conifers and deciduous species, but so far we do not have any information about possible differences between photoperiodic ecotypes at the phytochrome level. Northern and southern ecotypes have different responses to red:far red ratios, which could indicate differences in composition of their phytochrome systems, for example, the proportions of phytochrome A and B. Both phytochrome A and phytochrome B can be involved in photoperiodic responses. Experiments with transgenic hybrid aspen suggest that responses to photoperiod could be affected by the amount of phytochrome A present in plants. In deciduous species, the plant hormone gibberellin A1 (GA1) can completely substitute for a long photoperiod, and short day induced cessation of growth is preceded by a significant reduction of GA1 levels, particularly in the elongation zone. Photoperiodic control of GA metabolism is supported by several studies, but very little is known about the interaction between phytochrome and GA metabolism and/or responsiveness to GA1. Although our knowledge is still very fragmentary, available results suggest that cessation of growth and initiation of hardening in trees can be controlled both through the phytochrome and the GA mediated systems. Research with tree species is a tedious and slow process, but with the emerging new methods and approaches, we may expect exciting new results in the near future. 相似文献
8.
9.
就光周期对小悍蟋T a rta rog ry llusm inuscu lus若虫发育及成虫繁殖的影响进行了调查.结果表明,在30℃恒定长日(LD16 h∶8 h)条件下,小悍蟋若虫63 d内全部供试个体完成羽化,而在恒定短日(LD 12 h∶12 h)条件下,小悍蟋若虫120 d之内仍只有90%的个体完成羽化;将孵化后第7 d和第35 d的若虫自短日条件向长日条件转移,能够促进小悍蟋若虫的发育,而反方向的转移则对小悍蟋若虫的发育几乎不起影响.这表明小悍蟋若虫存在滞育现象,短日条件诱导滞育,长日条件解除滞育,并且低龄若虫对长日条件比较敏感.光周期不仅影响小悍蟋若虫发育,而且也影响成虫的繁殖.长日条件下的成虫产卵量显著多于短日条件下的成虫产卵量.但是,光周期对成虫产卵前期间无明显影响. 相似文献
10.
Dormancy induction in container-grown Abies seedlings: Effects of environmental cues and seedling age 总被引:1,自引:0,他引:1
Twelve-week-old container-grown seedlings of noble fir (Abies procera Rehd.) and Shasta red fir (A. magnifica A. Murr. var. shastensis Lemm.), both high-elevation species, were grown under controlled environments in a study of induction of terminal-bud dormancy. Eight treatment combinations of long (15 h) or short (11 h) photoperiods, warm (25°/20°C) or cool (18°/12°C) thermoperiods, and dry (–1.2 MPa) or wet (–0.6 MPa) moisture regimes were imposed upon seedlings for 12 weeks. Treatment factors significantly affecting the induction of dormancy in terminal buds of seedlings were identified over time. The results suggest that seedlings responded dynamically to dormancy cues. The warm/dry and cool/wet combinations induced dormancy in the first 2 weeks in noble fir and in the first week in Shasta red fir. Short-day/warm and long-day/cool combinations enhanced dormancy induction in weeks 3 to 4 in noble fir and in weeks 1 to 7 in Shasta red fir. Short days and cool thermoperiods independently hastened dormancy induction in noble fir in weeks 5 through 12. 相似文献