Effects of photoperiod on secretory patterns of growth hormone in adult male goats     

Jin Jin  Ken Sawai  Tsutomu Hashizume 《Animal Science Journal》2013,84(12):790-797

The aim of the present study was to clarify the effect of photoperiod on secretory patterns of growth hormone (GH) in male goats. Adult male goats were kept at 20°C with an 8‐h or 16‐h light photoperiod, and secretory patterns of GH secretion were compared. In addition, plasma profiles of prolactin (PRL), insulin‐like growth factor‐I (IGF‐I) and testosterone (T) were also examined to characterize GH secretion. GH was secreted in a pulsatile manner. There was no significant difference in pulse frequency between the 8‐h and 16‐h photoperiods. However, GH pulse amplitude tended to be greater in the group with the 16‐h photoperiod (P = 0.1), and mean GH concentrations were significantly greater in the 16‐h photoperiod (P < 0.05). The GH‐releasing response to GH releasing hormone was greater in the 16‐h than 8‐h photoperiod (P < 0.05). Plasma PRL and IGF‐I levels were higher in the 16‐h than 8‐h photoperiod (P < 0.05). In contrast, plasma T levels were lower in the 16‐h photoperiod (P < 0.05). These results show that a long light photoperiod enhances the secretion of GH as well as PRL and IGF‐I, but reduces plasma T concentrations in male goats.  相似文献   

Physiology and Regulation of Seasonal Nitrogen Cycling in Woody Plants     

《Journal of Crop Improvement》2013,27(1-2):237-259

Summary

Seasonal nitrogen cycling in trees is a mechanism for conserving and reusing nitrogen that may contribute to nitrogen use efficiency. In this review the physiological and molecular regulation of seasonal nitrogen storage is examined. Research using the 32 kDa bark storage protein gene, bspA of poplar (Populus) as a model system has revealed important facets regulating gene expression and subsequent nitrogen storage. Recent progress has demonstrated that bspA expression is a photoperiod response mediated by phytochrome and secondary messengers including Ca²⁺ and protein phosphorylation are involved in signaling pathways. Furthermore, evidence indicates that photoperiod modulated expression likely involves metabolic signaling mediated by glutamine and sucrose. A model is proposed that integrates the various facets of poplar bspa expression.  相似文献   

光照周期对尼罗罗非鱼幼鱼昼夜节律调节的作用     

刘曾宇  周志成  吕为群 《上海海洋大学学报》2019,28(2):180-189

为了研究尼罗罗非鱼幼鱼游泳行为在不喂食时是否存在昼夜节律和光照周期的调节作用,设计了光周期为光照(L)∶黑暗(D)=12 h∶12 h,持续的黑暗(DD),持续的光照(LL),光周期为L∶D=6 h∶6 h和光周期为L∶D=2 h∶2 h。结果表明:(1)光周期为L∶D=12 h∶12 h时,尼罗罗非鱼具有明显的昼夜节律,昼夜节律周期为(24. 3±0. 2) h;(2)尼罗罗非鱼的昼夜节律在持续的黑暗和光照下仍然存在,分别为(25. 1±1. 1) h和(25. 6±1. 0) h;(3)光周期为L∶D=6 h∶6 h时,尼罗罗非鱼仍具有明显的昼夜节律(12. 6±0. 5) h;(4)在光周期为L∶D=2 h∶2 h时,尼罗罗非鱼的昼夜游泳行为仍具有明显的昼夜节律,节律周期为(4. 0±2. 0) h。这些结果表明,尼罗罗非鱼具有以24 h为周期的内源性生物钟,但相比与外源性光照调控,内源性的生物钟对罗非鱼的调控较弱,外源性的光照周期才是调节尼罗罗非鱼幼鱼昼夜行为节律的主要因素。  相似文献   

Effect of photoperiod on development and reproduction of Megacopta cribraria(Hemiptera:Plataspidae)     

Zhe Xu  Juan Cui  Rui Bi  Wei Xu  Shusen Shi  Yu Gao 《中国油料作物学报(英文)》2019,(2):90-99

Megacopta cribraria (Hemiptera: Plataspidae) continually outbreaks due to suitable photoperiod in recent years. Effect of photoperiod on growth, development and reproduction of M. cribraria were assessed in this study. Results indicated that developmental duration, nutrient accumulation efficiency, and adult fecundity of M. cribraria were significantly different under 6 photoperiodical conditions. Developmental duration of nymph stage gradually tended to be shorter as day time increase. Body weights of 5th instar nymphs for 16 h and 4 h day time photoperiods were 5.2 mg and 4.6 mg, respectively. Moreover, longevity of adults tended to be longer as day time increase. However, for the short day photoperiod (4 L:20 D and 8 L:16 D), population showed no reproductive behaviors. Index of population trend increased with photoperiod extension and adults showed stronger reproductive capacity and longer longevity. This research identified the favorable photoperiodical conditions before outbreak. It may provided reference for ecological adaptability of M. cribraria, and contribute to the scientific basis for forecasting and controlling of M. cribraria.  相似文献   

不同地理种群松毛虫的光照周期反应   总被引：1，自引：0，他引：1       下载免费PDF全文

贾凤友 《林业科学研究》1993,6(1):52-57

  相似文献   

光照对马岗鹅季节性繁殖活动和内分泌的调控   总被引：2，自引：0，他引：2  

黄运茂  施振旦  李孝伟  刘志  刘颖 《畜牧兽医学报》2008,39(1):29-36

研究了光照对马岗鹅季节性繁殖活动和内分泌的调控。在整个试验期（2004.01.13-12.18）对照组接受自然光照,处理组接受人工控制的长短光照处理。在非繁殖期（4-7月份）,对照组公母鹅血浆PRL浓度升高,LH浓度和公鹅睾酮水平降低,鹅换羽;在繁殖期（8-3月份）,公母鹅血浆PRL水平下降,LH浓度和公鹅睾酮水平则上升。在处理组,延长光照均使公母鹅PRL浓度升高,LH浓度和公鹅睾酮水平降低,鹅群进入休产期并换羽;缩短光照则降低PRL水平,促进LH分泌和公鹅睾酮水平上升,鹅群进入繁殖期。整个试验阶段,两组中公鹅甲状腺素T3水平均无明显季节性变化,处理组和对照组母鹅平均产蛋48.8和26.3枚,前者比后者高85.6%。试验结果表明,长光照抑制,短光照促进马岗鹅繁殖活动,光照通过调节PRL和LH的分泌调控马岗鹅繁殖活动的季节性变化。  相似文献   

Effect of environmental factors and changes in the body condition score on the onset of the breeding season in mares     

Pouya Dini  Kaatje Ducheyne  Isabel Lemahieu  Wendy Wambacq  Hilde Vandaele  Peter Daels 《Reproduction in domestic animals》2019,54(7):987-995

Several methods have been proposed to advance the onset of the breeding season in horses. Most of them are based on the exposure to an artificial lighting period combined with hormonal treatments. Mares exposed to an artificial photoperiod are most often housed indoors where the ambient temperature is often higher than the outside temperature. Mares held in barns are also exposed to different daylight intensities than horses kept outside, depending on the architecture. In the current study, we evaluated the impact of ambient temperature, daylight intensity and changes in body condition score (BCS) on the timing of first ovulation after winter anestrus in mares exposed to an artificial photoperiod. Mares (n = 211) were housed in barns with different ambient temperature and daylight exposure but with the same artificial photoperiod exposure (except for a natural photoperiod control group). Artificial photoperiod as well as an increase in BCS over the winter significantly advanced the first spring ovulation. The BCS at the start and end of the anestrus period did not have an effect on the interval to first ovulation and neither did the modest increase in ambient temperature in the barn. However, a higher light intensity during the daytime significantly advanced the first spring ovulation. The results of this study suggest that exposure to more sunlight advances the onset of the breeding season. This effect is likely mediated through the biological effect of short wavelength blue light and its impact on melatonin suppression and biological rhythms. We suggest that greater/direct exposure to the blue light component of daylight improves the response to the artificial photoperiod. The results of the present study can further assist to optimize the conditions that lead to an efficient spring transition of breeding mares.  相似文献   

Conditioning alleviates reduced yield of smaller plugs of ‘Albion’ strawberry (Fragaria X ananassa Duch.) in off-season plasticulture production     

Edward F. Durner 《The Journal of Horticultural Science and Biotechnology》2018,93(4):433-440

The influences of plug size, planting density, and mulch colour on responses to photoperiod and nitrogen conditioning of ‘Albion’ strawberry (Fragaria x ananassa Duch.) plants were evaluated in off-season field production in New Jersey, USA. Three different sized plug plants (7.6 cm square pots, 24-cell plug trays, or 50-cell plug trays) were conditioned with natural days (ND, natural daylength) or long days (LD, natural daylength supplemented with 24 h incandescent radiation) for one week followed by ND plus 100 ppm nitrogen (N) for 4 weeks or LD plus 800 ppm N for 4 weeks. Plants were then established in plasticulture on black, white, or silver mulch. In a second experiment, plug plants (439 cm³) were conditioned with LD and nitrogen then established in plasticulture on black, white, or silver mulch at 3 planting densities (0.46, 0.23, and 0.16 m²?plant^?1 (2, 4, and 6 plants?m^?2)). Fruit were harvested from August through October in both experiments. Conditioning enhanced off-season fall production. White plastic enhanced survival, productivity, and fruit size and larger plugs were more productive than smaller ones. If smaller plugs are desired, conditioning prevents the reduction in yield observed with non-conditioned smaller plugs.  相似文献   

Characterization of the LH peak after short and long fixed‐time artificial insemination protocols in sheep raised in the tropics          下载免费PDF全文

Gabriela Azenha Milani Soriano  Felipe Rydygier de Ruediger  Marilice Zundt  Marco Aurélio da Cruz Nobre Gomes  Lilian Francisco Arantes de Souza  Ines Cristina Giometti  Guilherme de Paula Nogueira  Gustavo Ricci Zanelli  Fabiola Cristiane de Almeida Rego  Caliê Castilho 《Animal Science Journal》2018,89(9):1245-1252

The aim of this study was to evaluate the peak in luteinizing hormone (LH) and the pregnancy rate of sheep (Texel × Santa Inês) in the tropics using short‐ (6 days) and long‐term (12 days) progesterone protocols followed by artificial insemination (AI) both in and out of the breeding season. Experiment 1 was conducted within (IN) the breeding season (autumn, n = 36), and experiment 2 was conducted outside (OUT) of the breeding season (spring, n = 43). In each experiment, the sheep were divided into two groups (6 or 12 days) according to the duration of treatment with a single‐use progesterone release vaginal device (CIDR^®, Pfizer, São Paulo, SP, Brazil), and blood samples were collected from 10 animals per group every 4 hr to measure the LH and progesterone concentrations. In the spring, the characteristics of the LH peak did not differ between groups; but in the autumn, there were differences between groups at the beginning (G‐6 IN: 36.44 ± 5.46 hr; G‐12 IN: 26.57 ± 4.99 hr) and end of the LH peak (G‐6 IN: 46.22 ± 7.51 hr; G‐12 IN: 34.86 ± 8.86 hr). The results showed alterations in the LH peak during the breeding season only in the sheep undergoing the short‐term protocol.  相似文献   

Production and testing of plants regenerated from protoplasts of photoperiod sensitive genic male sterile rice (Oryza sativa L.)   总被引：1，自引：0，他引：1  

Qingzhong Xue  Kossi Edoh  Hong Li  Nengyi Zhang  Juqiang Yan  Susan McCouch  Elizabeth D. Earle 《Euphytica》1999,105(3):167-172

Plants were regenerated from protoplasts isolated from embryonic suspension cultures of N5047S, a photoperiod sensitive genic male sterile (PGMS) Japonica rice line. Flow cytometric analyses of nuclear DNA content identified some tetraploid regenerates whose agronomic traits could be distinguished from diploid regenerates. Pollen and female fertility of diploid protoplast-derived clones grown under different light and temperature conditions was compared. A promising PGMS protoplast clone, ZAU11S, was developed from these clones. Its male sterility was confirmed as a photoperiod × temperature interaction type. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献