Heat loss in sleeping garden warblers (Sylvia borin) during migration

For small songbirds, energy is often a limiting factor during migration and, for this reason, they are forced to alternate nocturnal flights with stopovers to rest and replenish energy stores. Stopover duration has a key role for a successful migration and may have an important impact on fitness. Thus, migrants need to optimize their energy consumption at this stage to reduce their permanence at the site. A recent study has shown that lean individuals reduce their metabolic rate when tucking the head in the feathers during sleep. The underlying mechanism is very likely a reduction in conductance, but the thermoregulatory benefit of the increased insulation has never been quantified yet. Here, we compared heat loss in individual migratory birds while sleeping in different postures. Using a thermal camera and a within-individual approach, we estimated that Garden Warblers can reduce their rate of heat loss by 54% by sleeping with the head tucked in the feathers. This energy saving has a relevant impact on the individual’s energy balance because it can account for up to 8.69% of daily energy expenditure during stopover. Our study provides novel and important information to understand the fundamental role of thermoregulatory strategies on bird’s energy management.     

Spring versus autumn leaf colours: Evidence for different selective agents and evolution in various species and floras

Red colouration is common in young and old leaves of broadleaf woody species. Assuming that leaf colours are adaptive, we examined, by comparing the colouration in young versus old leaves, the possibility that different selection agents may have operated on spring versus autumn leaf colouration. We observed spring versus autumn colouration in three very different woody floras (Finland, Japan and Israel) in order to allow for a broad ecological and evolutionary spectrum. The null hypothesis was that if the same selective agents operated in spring and autumn, it is expected that when spring leaves are red, they should always be red in autumn, and when spring leaves are green, they should be green or yellow in autumn. We found that green spring leaves are almost exclusively associated with yellow leaf colour at senescence in autumn. Species with red autumn leaves almost always have at least some red colouration in their spring leaves. However, about half of the species with red spring leaves have yellow autumn leaves. Brown autumn leaves were not common in the species we studied. As about half of the species with red spring leaves have yellow autumn leaves but not vice versa, we conclude that there are many cases in which the selecting agents for spring versus autumn leaf colour were not the same.     

Clinical use of dopamine antagonist sulpiride to advance first ovulation in transitional mares

Artificial photoperiod treatment is currently the best method to hasten the first ovulation of the breeding season in winter anoestrus mares. However, this is not easy to apply in large herds of mares and, to be effective, has to be planned in the northern hemisphere in December at the latest. Pharmacological treatments have been proposed as alternatives: GnRH agonists, progesterone or its synthetic agonist Altrenogest, and dopamino-antagonists, as pherphenazine, domperidone or sulpiride. Dopamino-antagonists protocols, beginning at a given day of the year, gave controversial results in terms of hastening ovulation. The aim of this study was to evaluate the efficacy of an up-to-21-d long dopamine antagonist (sulpiride) treatment on mares at the beginning of the spring transition for its ability to hasten estrous cyclicity. In Study 1, 49 seasonally-acyclic standardbred mares, maintained in paddocks under natural photoperiod, were treated with 1 mg/kg/d sulpiride at the evidence of the first follicle with of 25 mm in diameter until ovulation for a maximum of 21 d (Group S₁; n = 34) or left untreated (Group C₁; n = 15). Group S₁ and C₁ mares showed a follicle of 35 mm in diameter after 8 and 22 d (median; P < 0.05) and ovulated after 18 and 43 d, respectively (median; P < 0.05). Twenty-two/26 and 6/15 mares of the Group S₁ and C₁ ovulated within 30 d from the beginning of the treatment, respectively (P < 0.05). All the mares of the study cycled until Autumn, unless they became pregnant.In Study 2, pregnancy rates after the first ovulation of the year of 22 acyclic standardbred mares maintained in paddocks under natural photo-period, treated following the same protocol as Study 1 (S₂), and 47 untreated mares (C₂) were compared. In Groups S₂ and C_2, 63.6% and 61.7% of the mares became pregnant after the first cycle (P > 0.05) and 50.0% and 61.1% of the remaining became pregnant in the following cycles (P > 0.05), respectively.Beginning with sulpiride treatment when follicles were 25 mm in diameter resulted in a significant advancement of cyclicity in non-photo-stimulated mares. Pregnancy rates after artificial insemination of treated mares were similar to those of untreated animals.     

Confirmation of primitive chromosome structure in the hexaploid wheats

Summary Hybrids between Triticum aestivum cv Chinese Spring (CS) and T. dicoccoides of chromosome type E_1a showed only a few or no trivalents at meiosis, but both trivalents and quadrivalents were shown by hybrids with six other types. Since there is strong evidence that the E_1a type has the primitive chromosome structure of T. dicoccoides, Chinese Spring can be said to have the primitive chromosome structure of the hexaploid wheats in regard to reciprocal translocation.Contribution no. 51 from the Plant Germ-plasm Institute, Faculty of Agriculture, Kyoto University, Kyoto, Japan     

干旱、CO2和温度升高对春小麦光合、蒸发蒸腾及水分利用效率的影响

研究了干旱、CO₂浓度和温度升高对春小麦生育期、光合速率(P_n)、蒸发蒸腾(ET)及水分利用效率(WUE)的影响.结果表明,大气CO₂浓度升高(550、700μmol·mol^-1)虽可延长抽穗成熟期,但高温(日平均温度高于正常日平均温度约4.8℃)对生育期的影响远大于高CO₂影响,使得高CO₂、高温下抽穗成熟期缩短,且种子提前萌发;CO₂浓度升高和高温共同作用使各水分处理的小麦光合增强、气孔阻力增加、叶片水平的水分利用效率(WUEl)和群体水平的水分利用效率(WUE)增大,但对蒸腾速率影响不显著.对蒸发蒸腾的影响因不同的土壤水分而不同,在高(田间持水量的75%～85%)、中(田间持水量的55%～65%)水分条件下,高温和高CO₂使蒸发蒸腾增加,而在低水分条件(田间持水量的35%～45%)下,高温和高CO₂使蒸发蒸腾减少.     

春冬两季贺兰山岩羊集群特征的比较

20 0 3年 1 1～ 1 2月和 2 0 0 4年 4～ 6月在贺兰山国家级自然保护区对岩羊 (Pseudoisnayaur)春冬两季集群行为进行了初步研究。春季观察到的 2 1 8群 1 3 70只岩羊样本和冬季观察到的 3 1 0群 1 3 3 6只岩羊样本进行了比较 ,发现春季平均岩羊群大小为 (5. 5 7± 5 .3 8)只 ,冬季平均岩羊群大小为 (4. 2 9± 5 . 48)只 ,春冬两季岩羊集群大小季节性变化不显著 (P >0. 0 5 )。贺兰山岩羊在春冬两季 2～ 8只的群所占比例均居多 (春季 :85 . 3 % ;冬季 94 8% )。春季贺兰山岩羊群以雌性群 (4 0 . 3 % ,n =88)为主 ,冬季以混合群(4 9 7% ,n =1 5 4)和雌性群 (4 8 4% ,n=1 5 0 )为主。春冬两季雌性群平均大小间 (P >0 . 0 5 ) ,雄性群平均大小间 (P >0 . 0 5 )和混合群平均大小间 (P >0 . 0 5 )均无显著性差异。将春季和冬季贺兰山岩羊的雌雄比与雌幼比相比 ,春季观察到的雄性个体偏多 ,冬季观察到的幼体较春季多。     

Associations among spring-dependent aquatic assemblages and environmental and land use gradients in a Mojave Desert mountain range

In many arid landscapes, springs provide the only reliable source of water. Accordingly, both native species and human land uses, including diversion of water, livestock grazing, and recreation, tend to concentrate around springs and spring‐fed riparian areas. We examined whether species richness and composition of aquatic macroinvertebrates at 45 springs in the Spring Mountains, an isolated mountain range in the eastern Mojave Desert (Nevada, USA), could be predicted using readily measured environmental gradients and estimates of disturbance intensity. The Spring Mountains is a focus of regional conservation planning, and managers are charged with prioritizing its springs for conservation and rehabilitation. Our results suggested that species richness of aquatic macroinvertebrates in the Spring Mountains system may be greatest at intermediate levels of natural and human disturbance. Discharge and springbrook length appeared to be only weakly correlated with species richness, whereas neither elevation, nor water temperature, nor electrical conductance was significantly associated with species richness. Nestedness analyses demonstrated that species present in relatively depauperate locations tended to be subsets of the species present in locations that were richer in species, but that pattern did not appear to be driven by either disturbance intensity or by the environmental variables we measured. Disturbance intensity was not associated with the extent to which species presences and absences were predictable. Although our results should not be interpreted to mean that major environmental gradients and disturbance intensity have no effect on distributional patterns of aquatic invertebrates in the Spring Mountains, the ability of these variables to serve as predictors of species richness and composition may be relatively low. Springs and other wetlands in arid landscapes are characterized by isolation and unpredictable disturbances, and faunal responses to environmental gradients may tend to be individualistic and taxon‐specific.     

Nouveaux sites paléolithiques de l’oasis de Djizak

The present paper is devoted to the study of Paleolithic settlements recently discovered in the territory of the Djizak Oasis. Some Paleolithic settlements such as Yangikichlak, Azimboulak, Gourdara 1, 2 and Shachmai-Doston were discovered at the roof of the Nourata mountain range in the Farich district. Their cultural layers are not conserved but the single discoveries testify to the presence of prehistoric human camps in the Upper Paleolithic period. The lithic assemblage from the sites of the Djizak Oasis has some similarities with the material coming from the Tachkent site complex and from the Samarkand drainage basin. The discovery of the settlements and their later studies fill gaps on the Paleolithic map of the region.     

不同基因型春蚕豆对磷胁迫的适应性反应

利用不同作物或品种吸收利用土壤磷能力的差异提高磷素营养效率,是解决磷资源短缺的重要生物学途径.选择西北地区重要经济作物春蚕豆作为研究对象,选用3个不同春蚕豆品种(系),采用严重缺磷的碱性灌淤土,利用盆栽法研究了在不同供磷水平下不同基因型蚕豆的根系形态特征、酸性磷酸酶活性(APase)及产量的表现, 探讨不同基因型蚕豆对低磷胁迫的适应性反应.结果表明在整个生长过程中根长、根半径、根比表面积和根冠比变动最明显的是临蚕5号,分别为36.40%,65.10%、65.27%和13. 46%;缺磷条件下,蚕豆主要通过减小根半径,增加根长、根表面积,提高根冠比及体内酸性磷酸酶活性来实现对低磷胁迫的适应;不同基因型对低磷胁迫的适应能力不同;缺磷胁迫明显诱导各基因型蚕豆体内酸性磷酸酶活性的上升,临蚕5号增加最快为24.9%,8409为7. 79%,8354为7.29%;同一基因型的不同器官中酸性磷酸酶活性大小表现为根系>茎部>叶片 .根系酸性磷酸酶和根系形态参数可分别作为蚕豆耐低磷品种筛选的选择指标;缺磷导致作物减产,并且不同的基因型作物减产的幅度不同,临蚕5号缺磷比施磷减产30.98%,而8354 的产量在两个磷水平下变化不明显,说明临蚕5号对磷素的反应最强烈,为磷低效基因型,而 8354反应比较迟钝,为磷高效基因型.     

Spring cabbage peroxidases--potential tool in biocatalysis and bioelectrocatalysis

Two fractions of peroxidase activity, cationic Px-cat and anionic Px-ani, were isolated and partially purified (143.5- and 5.49-fold, respectively) from homogenate of spring cabbage heads. Optimum pH for both fractions is 6.0; however, Px-cat is almost equally active at neutral pH (7.0) while Px-ani reveals high activity in more acidic pHs (with 60% of maximum activity at pH 3.0). Optimal temperature for both fractions was 40 degrees C. Px-ani possessed much higher thermal stability at 40-50 degrees C (60% of remaining activity after 144h of incubation) than Px-cat. The peroxidases remained fully active during 4 weeks of storage at 4 degrees C. Kinetic studies revealed that Px-cat and Px-ani had lower apparent Km values for ABTS (0.0377 and 0.0625mM) and o-dianisidine (0.357 and 0.286mM) than for guaiacol (6.41 and 13.89mM). The best substrate for Px-cat was pyrogallol and for Px-ani-o-dianisidine. Px-cat immobilized on polyanionic PyBA-modified carbon electrode was found to produce linear repetitive signals upon consecutive additions of hydrogen peroxide during at least 1-week period and to work effectively under buffered and non-buffered conditions. These properties were comparable with those of commercially available horseradish peroxidase. Stability of the hybrid bioelectrocatalytic film and low costs of extraction and partial purification of Px-cat make it a highly promising enzyme for practical applications, including construction of bioelectrodes.