Stress modulation of cellular metabolic sensors: interaction of stress from temperature and rainfall on the intertidal limpet Cellana toreuma

In the natural environment, organisms are exposed to large variations in physical conditions. Quantifying such physiological responses is, however, often performed in laboratory acclimation studies, in which usually only a single factor is varied. In contrast, field acclimatization may expose organisms to concurrent changes in several environmental variables. The interactions of these factors may have strong effects on organismal function. In particular, rare events that occur stochastically and have relatively short duration may have strong effects. The present experiments studied levels of expression of several genes associated with cellular stress and metabolic regulation in a field population of limpet Cellana toreuma that encountered a wide range of temperatures plus periodic rain events. Physiological responses to these variable conditions were quantified by measuring levels of mRNA of genes encoding heat‐shock proteins (Hsps) and metabolic sensors (AMPKs and Sirtuin 1). Our results reveal high ratios of individuals in upregulation group of stress‐related gene expression at high temperature and rainy days, indicating the occurrence of stress from both prevailing high summer temperatures and occasional rainfall during periods of emersion. At high temperature, stress due to exposure to rainfall may be more challenging than heat stress alone. The highly variable physiological performances of limpets in their natural habitats indicate the possible differences in capability for physiological regulation among individuals. Our results emphasize the importance of studies of field acclimatization in unravelling the effects of environmental change on organisms, notably in the context of multiple changes in abiotic factors that are accompanying global change.     

不同膜下滴灌方式对设施黄瓜生理特性及水分利用效率的影响

为了探明黄瓜膜下分根交替滴灌的节水效果,为设施黄瓜节水灌溉提供理论依据和技术参数,以‘津优3号’黄瓜为试材,采用随机区组设计,以土壤田间持水量的65%为灌水下限,田间持水量的90%为灌水上限,研究了分根交替滴灌(APDI)、固定1/2根区滴灌(FPDI)和传统滴灌(CDI)3种灌溉模式对黄瓜生长、生理特性、产量与品质及水分利用效率的影响,结果表明:(1)随灌溉处理时间的延长,3种灌溉模式的单株叶面积和株高的差异越来越显著,而茎粗和叶片数差异不显著;(2)与传统滴灌相比,分根交替滴灌模式下黄瓜叶片净光合速率略有下降而蒸腾速率显著降低,水分利用效率显著提高;(3)分根交替滴灌处理下黄瓜可溶性蛋白、可溶性糖含量与传统滴灌相比差异不显著,Vc含量却显著增加;(4)分根交替滴灌模式下黄瓜产量比传统滴灌下降1.5%,而灌水量减少17%,水分利用效率提高18.6%,节水效果显著。综上所述,分根交替滴灌可以在保证设施黄瓜产量没有显著下降的前提下,改善品质和显著提高水分利用效率,可作为设施节水提质增效的一种灌溉模式,推广应用前景广阔。     

月季花发育过程中花色变化的生理生化研究

以月季‘仙境’为材料,观测其正面和反面花瓣在开花过程中6个阶段的颜色和其花色的L*、a*、b*、C*、h*值变化,花瓣组织结构,以及pH值、花色素含量、类黄酮含量、可溶性糖和可溶性蛋白含量,探讨月季花色的呈色机理。结果显示:(1)半开期时,花瓣正面红色最深,花色苷、类黄酮、可溶性糖含量最高,而可溶性蛋白含量则在盛开期时达到最高。(2)pH越小时,花瓣红色越深,而且pH值小范围内的变动,就能导致花色的改变。(3)花色素大部分集中分布在上表皮,并且上表皮呈圆锥形小突起、下表皮为扁平状,故上表皮花色深于下表皮,亮度小于下表皮。(4)a*正面与pH值、花色苷和可溶性糖含量呈正相关关系;a*反面与L*正面、L*反面、b*反面呈正相关关系;L*正面与b*正面、L*反面与b*反面呈极显著负相关关系。(5)众多影响花色呈现的因素中,正面(反面)花色主要是受到花色素苷(L*反面)的直接作用,其他因素则通过影响花色素苷(L*反面)间接影响花色的呈现。     

不同施氮水平下加工番茄植株生长和氮素积累与利用率的动态模拟

通过3年的大田试验,设置不同的氮素水平(0、75、150、300、450、600 kg·hm^-2)对不同施氮量下加工番茄地上部生物量、氮素累积及利用率的动态变化进行模拟.结果表明: 加工番茄地上部生物量、氮素累积量和氮素利用率随出苗后累积生理发育时间(PDT)的动态变化符合Logistic模型,氮素快速累积起始时间较地上部生物量快速累积起始时间早4～6 d(PDT);瞬时氮利用率随出苗后累积生理发育时间的动态变化呈先增加后降低的单峰曲线.不同施氮水平下,300 kg·hm^-2处理的氮累积量和地上部生物量最多,产量最高.根据Quadratic模型得出,北疆地区加工番茄滴灌栽培的理论适宜施氮量为349～382 kg·hm^-2.     

金黄地鼠与白化地鼠遗传生化基因位点概貌

目的建立金黄地鼠和白化地鼠遗传生化基因位点。方法选用小鼠和大鼠的遗传生化基因位点,采用蛋白质和同工酶醋酸纤维电泳的方法,对金黄地鼠和白化地鼠进行生化基因位点检测。结果建立了金黄地鼠和白化地鼠25个生化基因位点,分析金黄地鼠和白化地鼠遗传生化基因位点的多态性,为进一步研究金黄地鼠白化突变系的遗传机理奠定基础。结论金黄地鼠生化基因位点存在多态性,白化地鼠与金黄地鼠生化基因位点存在差异。     

Physiological responses and tolerance threshold to cadmium contamination in Eremochloa ophiuroides

Plant tolerance is one of the preconditions in soil phytoremediation. The physiological responses and tolerance threshold of centipedegrass (Eremochloa ophiuroides) were investigated under eight different Cd concentrations (0, 60, 120, 180, 240, 300, 360, and 420 mg Cd kg(-1)) in a sand culture system. The results showed that turf quality, leaf relative water content (RWC), leaf electrolyte leakage (EL), leaf osmotic potential did not show significant changes under 180 mg Cd kg(-1) compared with the control, and relative growth rate (RGR), turf density, leaf chlorophyll content, photochemical efficiency (Fv/Fm) did not show significant changes under 240 mg Cd kg(-1) compared with the control throughout the whole experiment. Regression analysis was used to determine the threshold Cd concentrations for each physiological parameter and the most sensitive parameter occurred by RWC of 197 mg Cd kg(-1) which was chose as Cd tolerance threshold in centipedegrass because under this concentration the plant did not show any significant difference with the control in all growth and physiological parameters measured in this experiment. The phytoextration rate of centipedegrass reached 0.87% in 36 d under 180 mg Cd kg(-10 treatment.     

The preimaginal stages of Pnigalio gyamiensis Myartseva & Kurashev, 1990 (Hymenoptera, Eulophidae), a parasitoid associated with Chrysoesthia sexguttella (Thunberg) (Lepidoptera, Gelechiidae)

The larval instars of Pnigalio gyamiensis Myartseva and Kurashev are described in detail for the first time. This species is a larval-pupal ectoparasitoid of Chrysoesthia sexguttella (Thunberg) (Lepidoptera, Gelechiidae), which forms leaf mines in the plant Chenopodium album L. (Caryophyllales: Amaranthaceae). The female of Pnigalio gyamiensis lays a single egg on the skin of the host larva or nearby it, without any significant preference for a particular variant. The presence of long hairs on its body provides the newly-hatched first larval instar with high mobility. Some peculiarities in this parasitoid-host relationship are described.     

Thermal thresholds as predictors of seed dormancy release and germination timing: altitude-related risks from climate warming for the wild grapevine Vitis vinifera subsp. sylvestris

Background and Aims

The importance of thermal thresholds for predicting seed dormancy release and germination timing under the present climate conditions and simulated climate change scenarios was investigated. In particular, Vitis vinifera subsp. sylvestris was investigated in four Sardinian populations over the full altitudinal range of the species (from approx. 100 to 800 m a.s.l).

Methods

Dried and fresh seeds from each population were incubated in the light at a range of temperatures (10–25 and 25/10 °C), without any pre-treatment and after a warm (3 months at 25 °C) or a cold (3 months at 5 °C) stratification. A thermal time approach was then applied to the germination results for dried seeds and the seed responses were modelled according to the present climate conditions and two simulated scenarios of the Intergovernmental Panel on Climate Change (IPCC): B1 (+1·8 °C) and A2 (+3·4 °C).

Key Results

Cold stratification released physiological dormancy, while very few seeds germinated without treatments or after warm stratification. Fresh, cold-stratified seeds germinated significantly better (>80 %) at temperatures ≥20 °C than at lower temperatures. A base temperature for germination (T_b) of 9·0–11·3 °C and a thermal time requirement for 50 % of germination (θ₅₀) ranging from 33·6 °Cd to 68·6 °Cd were identified for non-dormant cold-stratified seeds, depending on the populations. This complex combination of thermal requirements for dormancy release and germination allowed prediction of field emergence from March to May under the present climatic conditions for the investigated populations.

Conclusions

The thermal thresholds for seed germination identified in this study (T_b and θ₅₀) explained the differences in seed germination detected among populations. Under the two simulated IPCC scenarios, an altitude-related risk from climate warming is identified, with lowland populations being more threatened due to a compromised seed dormancy release and a narrowed seed germination window.     

Biofertilizers and/or some micronutrients role on wheat plants grown on newly reclaimed soil

Pot experiment was conducted to study the effect of biofertilizers (inoculation with different bacterial isolates), foliar spraying with some micronutrients (Mn, Zn, Fe and Mn+Zn+Fe) and their interaction on growth, physiological parameters and nutrients content of wheat plants grown on reclaimed soil. Pot experiment was conducted in the greenhouse of National Research center, The experimental design was split plot with four replicates. Four biofertilizer treatments (un‐inoculated, Bacillus polymyxa, Azotobacter chroococcum or Azosprillium barasilense) were used and randomly distributed in the main pots. The foliar treatments with micronutrients were randomly distributed in the sub plots. The growth parameters (plant height, leaf area, roots, shoots and whole plant dry weights and number of tillers & leaves per plant); some physiological parameters (soluble sugar %, protein %, polysaccharide %, chl. A+b μg cm^?1 leaf per plant, carotenoids μg g^?1, IAA mg kg^?1 and psll mol DCPIP reduced per mg chl. per h) and nutrient contents (N, P, K, Mg, Mn, Zn and Cu) of wheat plants were significantly increased by inoculating wheat grains with different bacteria as compared with un‐inoculated plants (control). The highest values of all the mentioned parameters were obtained by using Azospirillum brasilense followed by Azotobacter chroococcum and Bacillus polymyxa in decreasing order. Foliar spraying treatments significantly increased the growth parameters, physiological parameters as well as nutrients content of wheat plants as compared with control. Highest values were obtained by using (Mn+Fe+Zn) treatment followed by Zn, Fe and Mn in decreasing order. Micronutrients in wheat plants differed as the foliar treatments were differed, so application of any micronutrient individually significantly increased its content and enhanced the content of other micronutrients in wheat. Interaction between the used biofertilizers and foliar spraying with micronutrients significantly affected all the studied parameters of wheat plants, the highest were obtained by inoculating wheat grains with Azospirillum brasilense and spraying the plants with (Mn+Fe+Zn) treatment, while the lowest values were attained by un‐inoculated grains (control) and spraying the wheat plants with tap water (control). Effective microorganisms in combination with micronutrients could be recommended to farmers to lead higher wheat yield.     

人工饲料、转Bt水稻及其亲本稻苗饲养下二化螟种群适合度的比较研究

以人工饲料、转Bt水稻"克螟稻"(cry1Ab纯和基因型)及其对照亲本"秀水11"稻苗为供试寄主植物开展二化螟Chilo suppressalis(Walker)1～5龄幼虫的室内饲养试验,以明确不同龄期二化螟种群的生活史参数。试验结果表明:二化螟在低龄时死亡率最高。克螟稻对二化螟各个龄期表现出高抗性,其各个龄期在克螟稻上均不能化蛹,随着龄期的增加二化螟的耐受性增强。以秀水11和人工饲料饲养二化螟对其蛹期、成虫期、单雌产卵量、羽化率的影响无显著性差异,以人工饲料饲养的二化螟蛹重显著高于以秀水11饲养的二化螟的蛹重,蛹重与人工饲料饲养时间呈正相关。与秀水11幼苗相比,人工饲料饲养下有利于二化螟雌虫的分化。