北京地区不同秋眠级苜蓿品种适应性评价

对14个紫花苜蓿Medicago sativa品种在北京地区的表现进行观测,并对主要性状指标进行分析.结果表明:参试各品种秋眠级不同其春季生长速度、秋季生长速度、产草量及越冬率都有明显的差异,秋眠级高的品种生长速度快、产草量高,但越冬率低、秋眠级低的品种与之相反;地温也影响苜蓿生长速度;茎叶比与鲜干比各品种之间无明显变化,但与茬次有显著变化.     

四种暖季型草坪草对长期盐胁迫的生长反应

通过盐水灌溉法,研究了长期盐胁迫对4种暖季型草坪草优良新品系沟叶结缕草'Z123'、结缕草'Z080'、狗牙根'C291'和海雀稗'P006'生长的影响,以评价其抗盐性及对长期盐胁迫的适应性生长反应.结果表明,根据绿叶盖度和植株总干重,这4种草坪草的抗盐性依次为'Z123'＞'P006'＞'C291'＞'Z080'.长期的盐胁迫显著抑制了'Z123,和'Z080'的叶重、枝条干重和枝条长度,而'P006'和'C291'在10～20 g/L以上的盐度下才受显著抑制.'Z123'、'C291'和'P006'可以分别在20,10和5 g/L以内的盐度下维持稳定的枝条数量,血'Z080'在5 g/L下显著降低.5～10 g/L左右的低盐度对4种草坪草地下茎和根系生长的影响不显著,较高盐度下才受显著抑制,但'P006'和'C291'在5 g/L下具有更稳定的根系干重.长期盐胁迫不同程度地提高了4种草坪草的地下部分地上部分干重比,但抗盐越弱的草比值增加越快.不同草坪草的同一器官对盐胁迫的反应不一致,反应了其抗盐机制的差异.     

Heart rate variability parameters as markers of the adaptation to a sealed environment (a hypoxic normobaric chamber) in the horse

Simulated hypoxic normobaric devices have been used in human beings in order to enhance endurance capacity. These devices are sealed chambers where the athletes are supposed to stay for at least 6–8 hr daily. The current research assesses the changes in time‐domain, spectral and non‐geometrical heart rate variability (HRV) parameters in 6 horses subjected to progressive duration periods inside of a hermetically sealed chamber. It was pursued, firstly to evaluate the intensity of the stress experienced by the animals and secondly to elucidate whether the horses might require an acclimation period before implementation of hypoxic conditions. HRV parameters were monitored for 6 days: day 0 (6‐hr duration; in paddocks; basal conditions), and days 1, 2, 3, 4 and 5 (1, 2, 3, 4 and 6 hr inside the chamber every day respectively). During day 1 and during the first hours of days 2 and 3, compared to day 0, horses presented increased HR and SDHR values and decreased RR interval duration. SD1 values decreased on some hours of days 2 and 3, but differences with day 0 were not found on day 1. Increased SDNN, RMSSD, SD1 and SD2 values were observed on days 4 and 5. These results showed an activation of the sympathetic activity together with an attenuation of the parasympathetic activity during the days 1 to 3. Increased parasympathetic activity was found only during the first hours of days 4 and 5. Spectral parameters experienced minor variations, with increased LF_peak and LF% during some hours of days 4 and 5. In conclusion, at least 3 days are needed to adapt the horse to a sealed environment before starting to subject the animals to hypoxic conditions. When the horses were acclimatized, however, a minor stress was detected with they spent more than 4 hr inside of the chamber.     

Study on Karyotype of Hobby (Falco subbuteo) and Kestrel (Falco tinnunculus)

IntroductionHobbiesandKestrelsaremiddleandsmallbirdsofpreyinFalconiformes,withverywidedistributioninChina,livingindifferenttypesofforests,shrubbery's,forestedges,waterareasornearinhabitants.Theylivesolitarilyorinpairs,flyveryrapidlyandpreyonsmallmammalssuchasrodents,youngbirdsandalsoinsects.Theirfoodhabitisverybeneficialtothepreservationofforestsandtheregulationoftherelativeequilibriumofforestecosystems,sothattheyarelistedintheprotectedanimalsClasslllilBirdsofFalconiformesinChinaareclassifi…     

Study on karyotype of Hobby (Falco subbuteo) and Kestrel (Falco tinnunculus)

This paper reported karyotypes of the Hobby and Kestrel collected from the suburb of Qiqihaer City. These karyotypes were compared and analyzed, on the basis of the study of karyotypes of nine birds species in Falconiformes by Bian Xiaozhuang and Li Qingwei. It was considered that differences in habits of birds and ecological environment not only cause falcons to differ from others, but also differences in a genus, even within a species. This difference may result from fusion of microchromosomes.     

Endophytic bacterial communities in the periderm of potato tubers and their potential to improve resistance to soil-borne plant pathogens

To evaluate whether the location of bacterial endophyte communities contributes to disease resistance in potato tubers ( Solanum tuberosum ), the population density, biodiversity and antibiotic activity of endophytic bacteria was examined from the tuber peel (periderm plus top 3 mm of tissue) of four cultivars (Russet Burbank, Kennebec, Butte and Shepody). There were no significant differences for population density of bacteria among the layers of peel examined and no cultivar × peel layer interaction. Endophytic bacteria from several layers of peel were challenged in in vitro bioassays to the soil-borne plant pathogens Fusarium sambucinum , Fusarium avenaceum , Fusarium oxysporum and Phytophthora infestans (mating types A1 and A2). In general, antibiosis of bacterial endophytes against these pathogens was significantly higher ( P  = 0.01) in isolates recovered from the outermost layer of tuber peel and decreased progressively toward the centre of the tuber. Antibiosis against P. infestans was variable, with a progressive decrease in antibiotic activity from outer to inner layers of peel occurring in cvs Russet Burbank and Kennebec only. For antibiosis there were significant cultivar × peel, and cultivar × pathogen interactions ( P  = 0.01). In all cases the inhibitory activity of endophytic bacteria was significantly greater ( P  = 0.01) against the A1 than the A2 mating type of P. infestans . In four of seven cases, where the same species of bacteria were recovered from all three peel layers, antibiosis to pathogens decreased significantly ( P  = 0.01) with depth of recovery (from the periderm to inside the tuber), indicating that in certain communities of endophytic bacteria, defence against pathogens may be related to bacterial adaptation to location within a host and may be tissue-type and tissue-site specific.     

Local adaptation studies and conservation: Parasite–host interactions between the endangered freshwater mussel Unio crassus and its host fish

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Settlement behavior of American lobster (Homarus americanus): effect of female origin and developmental temperature

The benthic settlement success of American lobster (Homarus americanus) postlarvae is a key factor in population dynamics, with the temperature being a key factor. Given the spatial distribution of the species, its pelagic larvae probably encounter various thermal zones during development. Little information is available on the ability of lobster larvae to acclimate to temperature or if this ability varies among geographic areas. The main objectives of this study were to characterize (i) the settlement behavior of the postlarvae in relation to (a) temperature during larval development and (b) the geographic origin of the maternal parent and (ii) the behavioral response of postlarvae with different thermal histories in the presence/absence of a thermocline. Results did not support the hypothesis of thermal adaptation among local populations, as settlement behavior of postlarvae did not differ among females from different geographic regions. In contrast, larval survival and settlement behavior and postlarval energetic conditions varied with development temperature. Behavioral plasticity in the benthic settlement was observed in relation to temperature structure of the experimental water column. This study suggests that there may be links between development temperature and the natural variability in survival and settlement of American lobsters. Findings emphasize the need for an integrated approach in lobster recruitment studies with the inclusion of behavior in dispersion models.     

An outbreak of Shewanella putrefaciens group in wild eels Anguilla anguilla L. favoured by hypoxic aquatic environments

Microbiological analyses were conducted on wild eels from the L′Albufera Lake (Spain). A total of 174 individuals were collected in two surveys (i.e. year 2008 and autumn–winter 2014) among those caught by local fishermen into the lagoon. The prevalence of Shewanella putrefaciens group was 1.7% in 2008 and rose above 32% in 2014. It was due to an outbreak of shewanellosis that presented a morbidity rate of 64%. S. putrefaciens group strains were isolated as pure cultures from the sick eels that showed white ulcers surrounded by a reddish inflammation, damage of the mouth, extensive skin discoloration, exophthalmia, ascites and bad odour. The S. putrefaciens group was recovered from freshwater samples taken at the L′Albufera system, along autumn–winter 2015. Its counts significantly increased in freshwater parallel to hypoxia and temperature rising. Shewanellae strains were identified as S. putrefaciens and S. xiamenensis by 16S rRNA gene sequencing. These isolates recovered from sick eels or freshwater were virulent for European eel by IP challenge (LD₅₀ 10⁶ CFU g^?1 body weight). They also caused 30–38% cumulative mortality, in European eels challenged by a 2‐h bath (10⁷ CFU mL^?1). These results suggest that shewanellosis could be transmitted through water highlighting the fact that hypoxic conditions increase this bacterium levels in water.     

通渭县生态放养鸡引进品种适应性试验

本试验基于甘肃省通渭县气候特点和生态资源优势,以该县永达碧林源养殖农民专业合作社为示范点,通过对引进芦花鸡、绿壳蛋鸡的适应性开展观测试验,继而筛选出成活率高、经济效益好、抗病能力强,适宜通渭县地区内放养环境的放养鸡品种,从而稳步推进通渭县养鸡业生产方式转变,发展节约型、健康型养鸡业,发展生态放养试验示范促进新技术在全县范围内推广。