Orange peel fragment improves antioxidant capacity and haematological profile of Nile tilapia subjected to heat/dissolved oxygen‐induced stress

This study evaluated the ability of orange peel fragment (OPF) to act as a functional feedstuff, influencing growth, haematological profile, and antioxidant enzyme activity of Nile tilapia subjected heat/dissolved oxygen‐induced stress (HDOIS). A group of 440 male Nile tilapia (31.7 g ± 0.34) was randomly distributed in 40 250‐L aquaria (11 fish/tank) and fed five practical diets with graded levels of OPF at 0%, 0.2%, 0.4%, 0.6%, and 0.8% for 70 days. The diets were formulated to contain 30% crude protein and 18 MJ/kg crude energy. After the feeding period, growth performance was evaluated and six fish per treatment were sampled for haematological profile and antioxidant enzyme activity, before and after HDOIS. Then, fish were subjected to HDOIS (32°C/2.3 mg/L dissolved oxygen) for three days and the same haematological profile and antioxidant enzyme activity were determined. There was no effect of OPF on the haematological profile, either before or after HDOIS. The polynomial regression model was used to express the relationship between antioxidant enzymes activity and OPF supplementation level. The maximum activity of superoxide dismutase, catalase, and glutathione peroxidase was reached at 0.66%, 0.63%, and 0.68% of OPF respectively. Results of the present study suggest that a dietary supplementation level of 0.63%–0.68% of orange peel fragment was appropriate to maintain Nile tilapia haematological profile and improve its antioxidant capacity under HDOIS.     

What can we learn by studying dead fish fry?

This study investigated the influence of temperature (4, 8 and 12°C) on development and survival of brown trout (Salmo trutta) fry. The three aims of this study were: (a) to propose a typology of malformations; (b) to compare malformation types between live and dead fry and (c) to establish relationships between temperature and malformation occurrences. It was found 20 single malformations and 39 combinations of two or more malformations. Comparison between dead and live fry at different development stages (hatching, emergence and first food intake) showed that malformations of yolk sac were predominant at hatching and then decreased, while malformations of skeleton or multiple malformations were higher thereafter. All dead fry, and only 14% of live fry were malformed. Dead fry were mainly characterized by yolk sac malformations and multiple malformations whatever the temperature. Live fry showed a higher rate of skeleton malformations at 12°C, and the different types of malformations were equally represented at two other temperatures (4 and 8°C). To conclude, it is suggested that some malformations (yolk sac at hatching, yolk sac associated with skeleton malformations at emergence and skeleton at first food intake or combinations of malformations at all stages)might be lethal as they were founding dead fry and that temperature influences differently the occurrence of malformations.     

四川省犍为县越冬代稻显纹纵卷叶螟冬后虫口密度和生物学特性

稻显纹纵卷叶螟Cnaphalocrocis exigua(Butler)是稻纵卷叶螟Cnaphalocrocis medinalis(Guenée)的近缘种,目前主要在我国西南稻区发生为害。为了明确稻显纹纵卷叶螟在四川省犍为县冬后的虫源状况,我们开展了稻显纹纵卷叶螟冬后虫源结构调查,观察了冬后种群的生物学特性,并研究了温度对其的影响。结果显示,犍为县舞雩乡和罗城镇稻显纹纵卷叶螟冬后虫源密度分别为7.09头/25丛和5.50头/25丛。调查时稻显纹纵卷叶螟主要以蛹为主,有少量幼虫。稻显纹纵卷叶螟越冬代雌雄蛹重分别为11.56 mg和11.82 mg,性比(雌∶雄)为1.29∶1,蛹被寄生率为16.5%。20℃、22℃、24℃和室温下稻显纹纵卷叶螟越冬代蛹羽化率分别为44%、38%、52%、43%。不同温度下,稻显纹纵卷叶螟产卵量及成虫寿命无显著差异。本研究结果对于开春稻显纹纵卷叶螟的防控具有指导意义。     

春季低温对小麦颖果发育的影响

为了探明春季低温（倒春寒）导致小麦减产的细胞学机理，以扬麦15为材料，在小麦幼穗处于雌雄蕊分化期至药隔期之间时，设置-3 ℃低温处理，通过树脂半薄切片对颖果不同发育时期的形态结构进行观察。结果表明：（1）在颖果发育早期，低温促进了颖果的长度生长，抑制了宽度生长；与对照相比，低温处理组小麦颖果发育进程缩短；（2）低温处理组颖果果皮发育早，中果皮降解速度快；（3）低温处理增加了胚乳淀粉体的积累量，降低了蛋白体的积累量，发育后期胚乳充实度显著低于对照组；（4）与对照相比，低温处理后颖果韧皮部面积和珠心突起传递细胞面积增大。以上结果表明，春季低温处理更有利于养分运输组织的发育，使得灌浆时间缩短，最终导致淀粉积累量增加及颖果早熟。     

海带孢子体光合活性对不同温度和光照的响应

为了从生理生态学角度解答温度和光照对海带孢子体生长过程的影响,探索海带孢子体对温度和光环境的生理响应机制,实验在测定养殖海域海带孢子体生长参数的基础上,设定了6、10、14和18°C 4个水温梯度的海带孢子体暂养实验,以及它们在0、25、70、133、230、317、421、582、786μmol photons/(m2·s) 9个光合有效辐射(PAR)梯度下的光合活性荧光参数测定。结果显示:①在6°C水温条件下,海带孢子体荧光参数Fv/Fm和Fv/F0最大,分别为0.71和2.40;在18°C水温条件下,其Fv/Fm和Fv/F0最小,分别为0.65和1.85;②暂养海带孢子体的光化学淬灭(qP)和非光化学淬灭(qN或NPQ)在18°C水温条件下达到最大,分别为0.92和3.29;③海带孢子体的快速光曲线随着光合有效辐射(PAR)的增强呈现先上升后下降的趋势;④海域养殖海带孢子体的最大叶长增长速率、叶宽增长速率和干重增重率分别为1.34 cm/d、0.33 cm/d和1.01 g/d。研究表明,海带孢子体干重生长率变化与不同水温条件下的快速光曲线变化一致,高温抑制了海带孢子体光合效率;当环境光合有效辐射大于样品光饱和点(Em)后,海带孢子体相对电子传递速率下降,光合作用受到抑制。     

Assessment of Vein Diameter and Body Surface Temperature after High-Intensity Laser Therapy (HILT) on the Tarsal Joint in Healthy Horses

The aim of the study was to assess the influence of high-intensity laser therapy (HILT) on vein diameter and on body surface temperature changes in the tarsal joint area in a group of clinically healthy racehorses. The hypothesis of the study was that HILT increases vein diameter and body surface temperature in healthy tissue. The study involved 16 Thoroughbreds being subjected to ultrasonographic examination to assess changes of diameter of the cranial branch of the medial saphenous vein and thermographic examination to indicate temperature change of the dorsal surface of the tarsal joint, just before and immediately after HILT treatment. Vein diameter and mean surface temperature of the tarsal joint significantly increased after HILT treatment. In addition, the study was the first to describe the photothermal effect of HILT in healthy horses. More studies are necessary to specify the parameters of the procedure, that is, wavelength, energy density, or time of the procedure, depending on the patient’s individual characteristics and type of tissue.     

海南岛西部橡胶人工林冠层温度变化及其与微气象要素的关系

冠层温度是表征植物生理生态过程及能量平衡状况的重要参数之一。为探讨热带森林冠层温度在不同时间尺度下的变化规律并且初步分析环境因素与冠层温度的关系,本研究利用红外温度传感器测定了海南岛西部橡胶人工林2017年全年的冠层温度数据以及同步得到的冠层微气象资料,对干季和湿季下海南岛西部橡胶人工林冠层温度（T_c）与大气温度（T_a）特征进行了分析,同时结合微气象因子进行了讨论。结果表明：橡胶人工林冠层温度全年各月日变化都为单峰曲线,相比T_a,T_c具有明显的位相前移、变化加剧的特点。白天林冠边界层处于不稳定状态,林冠为土壤-植物-大气连续体（Soil-Plant-Atmosphere Continuum,SPAC）的热源;夜晚林冠边界层为逆温层结,呈稳定状态,林冠为SPAC的冷源。湿季冠层温度高于干季。若仅考虑T_a,T_c与T_a之间具有很好的线性关系,其线性方程为T_c= 1.033T_a-0.656;若同时考虑大气温度（T_a）、净辐射（R_n）、相对湿度（RH）与风速（V）等微气象因子,其复相关系数表明全年均呈极显著相关,偏相关系数表明干季冠层温度变化主要受T_a、R_n和RH的影响,其次受V的影响;湿季主要受T_a与RH的共同作用,R_n与V对其的影响相比可忽略不计。此研究结果初步揭示了橡胶人工林冠层温度的全年变化规律及其与众多微气象因子之间的关系,为进一步探究冠层温度变化及其影响机制提供科学依据。     

外源5-氨基乙酰丙酸对低温胁迫下茶树叶片光合及生理特性的影响

通过对陕茶1号（耐低温型）和金牡丹（低温敏感型）2个茶树品种在冬季自然低温胁迫下喷施不同浓度（0、10、30、50 mg·L^-1）的外源5-氨基乙酰丙酸（5-aminolevulinic acid,ALA）,探究外源ALA对低温胁迫下茶树叶片光合荧光特性及生理特性的调控作用。结果表明,适宜浓度的外源ALA对低温胁迫下茶树叶片净光合速率、气孔导度、胞间CO₂浓度、蒸腾速率、PSⅡ最大光化学效率及PSⅡ潜在活性具有促进作用,能够提高水浸出物、咖啡碱、游离氨基酸、儿茶素类物质、茶氨酸、可溶性糖、可溶性蛋白等生理活性物质含量的累积;外源ALA能够提高低温胁迫下茶树光合作用的能力并改善茶叶品质,其中50 mg·L^-1的ALA处理能有效提高陕茶1号应对低温胁迫的能力,10 mg·L^-1和30 mg·L^-1的外源ALA对金牡丹应对低温胁迫具有较好的缓解效用。     

长江下游不同生态区双季优质晚稻生长特性和温光利用差异

【目的】研究在机插条件下长江下游不同生态区各类型优质晚稻产量、生长特性和温光利用的差异,为选择适宜在该地区作为双季种植的优质晚稻品种提供参考依据。【方法】以2016年和2017年筛选适合长江下游机插的双季优质晚稻为材料(常规籼稻、杂交籼稻、常规粳稻和常优杂粳共20个品种),比较在机插条件下浙江富阳(30.05°N, 119.95°E,海拔17.9 m)与安徽庐江(31.15ºN, 117.16ºE,海拔14 m)两个生态区在产量、生育期、干物质积累以及温光利用方面的差异。【结果】各类型晚稻产量高纬度试点均高于低纬度试验点。与浙江富阳点相比,安徽庐江点种植的常规籼稻、杂交籼稻、常规粳稻、常优杂粳稻产量分别高11.1%、12.9%、6.6%和12.4%。同一试点种植时,常优杂粳产量最高,常规籼稻最低。高纬度点种植时,生育期延长,干物质积累量增加。高纬度点生育期延长杂交籼稻最长(10.4 d),干物质积累量高纬度点增幅常规粳稻最大(齐穗期和成熟期分别增加11.93%和9.44%)。同一试点种植时,干物质积累量杂交稻大于常规稻。籼稻灌浆期和全生育期累积的有效积温两个纬度点差异不明显,但日照时数和太阳辐射及其利用率均是高纬度点显著高;粳稻灌浆期和全生育期累积的有效积温高纬度点明显较低,累积日照时数高纬度点变化不明显,而累积太阳辐射则显著增加;温光资源利用率的变化趋势与此一致;同一试点种植时,生育期、干物质积累量以及温光资源利用率均是粳稻大于籼稻。【结论】晚籼稻在安徽庐江点种植时能充分利用温光资源从而提高产量,晚粳稻对温光资源利用率差异不明显,安徽庐江点产量增加的原因是生育期延长和干物质增加。     

长期少免耕对中国东北玉米农田土壤呼吸及碳氮变化的影响

在黑土区37年不同耕作模式定位试验田，采用原位法比较常规旋耕灭茬起垄（CT）、旋耕留高茬行间深松-少耕（RT）、免耕（NT）和深翻（PT）4种耕作模式土壤呼吸速率及其与土壤温度和湿度的关系，测定土壤总碳氮、无机氮，微生物碳氮的变化。结果表明，玉米生育期间土壤呼吸呈单峰变化，开花期达最大值，生长季平均呼吸速率依次为RT > NT > CT > PT。4个处理土壤温度与土壤呼吸速率间存在显著指数关系。不同耕作模式0~10 cm土壤温度可解释土壤呼吸速率变异的38.3%~67.9%，温度敏感性系数Q10范围为2.1~5.3；RT和NT处理显著提高0~20 cm土壤碳氮含量；RT处理在0~20 cm土壤中微生物碳含量均高于CT、NT和PT处理。RT处理土壤呼吸对温度响应提高，RT和NT处理显著增加上层土壤总碳氮含量，利于土壤质量提升。