设施蔬菜连作障碍综合防治技术

在设施农业生产中,高肥栽培是非常普遍的现象,经过2～3年就会产生较严重的土壤次生盐渍化,产生土壤连作障碍,影响产量和经济效益,通过工程洗盐和土壤消毒可使土壤恢复原来的生产性能。     

Indirect changes associated with a selection program for increased seed-yield in wild species of Lesquerella (Brassicaceae): Are we developing a phenotype opposite to the expected ideotype?

Seed-yield stability, frequently associated with drought-tolerance strategies, is one of the main breeding objectives for the development of crops for semi-arid mediterranean-type environments. Since breeding of new industrial crops targeted for arid lands is not appreciably different from that of traditional crops, higher yield is achieved by increased harvest-index, at the cost of losing traits associated with drought-tolerance and reduced seed-yield stability. Using Lesquerella as a model we compared selected and unselected accessions of annual (L. gracilis and L. angustifolia) and perennial (L. pinetorum and L. mendocina) genotypes grown in field experiments in Patagonia, Argentina. Our objective was to assess the effects of breeding for increased seed-yield on traits related to the main characteristics that define the most common ideotype for mediterranean-type environments: early vigor, conservative growth strategy post-anthesis and reserves storage. Our specific question was: Have any of the attributes associated with seed-yield stability been indirectly selected during the domestication process? Our results show that these characteristics were reduced or lost, in selected lines compared to their wild relatives. Early vigor was lower in selected accessions and was associated mainly with reduced relative growth rate and CO₂ assimilation. During the reproductive period the growth strategy was changed by selection towards a non-conservative and more acquisitive resource use strategy. Traits associated with this strategy were linked to higher water use efficiency and growth capacity (higher CO₂ assimilation rate, specific leaf area, and leaf allocation), but also with loss of structural adaptation to low resource environments (i.e. low specific leaf area), an increase in nutrient and water demands, and reduced nutrient use efficiency. Carbohydrates accumulation pre-anthesis was lower in selected accessions of all four species, and also, just in perennials we found lower reserves storage post-anthesis. These changes in the pattern of carbohydrates accumulation could be associated to lower seed-yield stability due to the loss of buffer capacity linked with the use of pre-anthesis reserves for seed filling. On the other hand, in perennial species lower reserves storage after seed harvest could reduce plant longevity and survival. We conclude that indirect changes occurred during the preliminary domestication of both annual and perennial species of Lesquerella used in our experiment. These changes were against those required if these species were to be developed as crops for semi-arid, mediterranean environments and should result in low seed-yield stability.     

山东设施渔业发展现状及对策建议

设施渔业是通过科学的管理和先进的养殖设备,实现水产养殖优质、高产、高效的一种新的生产方式,是现代渔业发展的必然趋势。山东省是水产养殖大省,其设施渔业的发展也一直走在全国的前列。文章在描述了设施渔业的定义和产业特点之后,结合山东省发展设施渔业的条件,在现状描述的基础上,针对其在设施渔业发展中存在的问题,提出了相关对策建议。     

Perceptions and representations of biodiversity in Lausanne,Switzerland: Acknowledging the importance of residential environments

While the ecological mechanisms involved in biodiversity loss within urban environments are widely studied, the literature often overlooks its social-ecological drivers. One of these drivers is the relationship between perceptions and representations of ecosystems and species within specific residential contexts. This study therefore aims to address the following questions: how do residents perceive biodiversity in relation to their social representation of nature within specific residential environments? Are there differences in the social representation and perception of greenspace types and species based on residents' demographic attributes (gender and age) and characteristics of their place of residence (district and housing types)? Through a quantitative survey and the analysis of 148 responses from Lausanne residents using textometry, cartography, and inferential statistics, this research demonstrates two main findings. Firstly, it confirms that the perception of species remains limited, which aligns with previous scholarly work. Secondly, it reveals that the social representations of nature and biodiversity can either correlate with or be disconnected from the perceptual process at the ecosystem level, depending on the residents' living environments. The impact of residential environments on biodiversity perception and representations is discussed, along with the implications of iconic biodiversity traps for raising public awareness about biodiversity preservation in cities.     

奶水牛瘤胃大口径瘘管安装手术及术后护理

瘤胃瘘管是用于研究反刍动物消化代谢、瘤胃微生态环境、生理生化等指标试验的手段之一,可广泛应用于反刍动物营养科研实验中。试验采用外科手术方法对 4 头奶水牛进行人造瘤胃瘘管安装,经约4周的术后护理。结果表明：术牛精神状态、体温、食欲、大小便等指标均表现正常。术后15d经检查发现,术牛的瘤胃壁与腹膜、腹肌及皮肤愈合粘连在一起,形成自然瘘口,没有出现刀口或腹腔感染的现象。说明该手术方法可操作性强,过程简单,用时短,术后瘘管密闭性好,创口恢复快、无感染;奶水牛能正常存活。     

新疆绵羊及其环境中李氏杆菌的生态分布多样性调查

对新疆健康绵羊及其相关环境如青贮饲料、饮水、土壤、鸟粪中李氏杆菌(Listeria)种群采用改良国标法(4789.30-2010)进行生态分布多样性调查,并对分离的单核细胞增多性李氏杆菌(L.monocytogenes)采用PCR方法进行溶血素基因(hly)和血清型检测。结果:514份样本中,共检出阳性样本26份,平均阳性率为5.1%,其中羊体分离率为6.2%(22/353),饮水分离率为33%(2/6),鸟粪分离率为3.0%(2/67),其余样本均为阴性;26份阳性样品中,检出单核细胞增多性李氏杆菌5株,塞氏李氏杆菌(L.seeligeries)21株,且5株单核细胞增多性李氏杆菌均检出溶血素基因,血清型为1/2a。     

Antelope adaptations to counteract overheating and water deficit in arid environments

Many arid areas have very severe climates with extremely high summer temperatures, strong solar radiation, and a lack of drinking water during the driest season. Therefore, antelopes living in arid areas are forced to solve two main problems: avoiding overheating and maintaining water balance.Generally, there are physiological, morphological, and behavioral mechanisms for antelope adaptations to arid environments. Among the mechanisms, behavioral adjustments have a minimal cost and are activated...     

Deep-Sea Natural Products from Extreme Environments: Cold Seeps and Hydrothermal Vents

The deep sea has been proven to be a great treasure for structurally unique and biologically active natural products in the last two decades. Cold seeps and hydrothermal vents, as typical representatives of deep-sea extreme environments, have attracted more and more attention. This review mainly summarizes the natural products of marine animals, marine fungi, and marine bacteria derived from deep-sea cold seeps and hydrothermal vents as well as their biological activities. In general, there were 182 compounds reported, citing 132 references and covering the literature from the first report in 1984 up to March 2022. The sources of the compounds are represented by the genera Aspergillus sp., Penicillium sp., Streptomyces sp., and so on. It is worth mentioning that 90 of the 182 compounds are new and that almost 60% of the reported structures exhibited diverse bioactivities, which became attractive targets for relevant organic synthetic and biosynthetic studies.     

Changes in rainfall partitioning caused by the replacement of native dry forests of Lithraea molleoides by exotic plantations of Pinus elliottii in the dry Chaco mountain forests,central Argentina

The replacement of native dry forests by commercial (exotic) tree plantations could generate changes in rainfall partitioning, which further affects the water cycle. In this study, we determined (i) the rainfall partitioning into interception, throughfall and stemflow, (ii) the role of rainfall event size on rainfall partitioning, (iii) the pH of water channelized as throughfall and stemflow, and (iv) the runoff in Lithraea molleoides (a native species) and Pinus elliottii (an exotic species) stands in the dry Chaco mountain forests, central Argentina. On average, interception, throughfall and stemflow accounted for 19.3%, 79.5% and 1.2% of the gross rainfall in L. molleoides stand, and 32.6%, 66.7% and 0.7% of the gross rainfall in P. elliottii stand, respectively. Amounts of interception, throughfall and stemflow presented positive linear relationships with the increment of rainfall event size for both tree species (P<0.01 in all cases). Percentages of interception, throughfall and stemflow were all related to the increment of rainfall event size, showing different patterns. With increasing rainfall event size, interception exponentially decreased, throughfall asymptotically increased and stemflow linearly increased. Both P. elliottii and L. molleoides stands presented significant differences in the pH values of water channelized as throughfall (6.3 vs. 6.7, respectively; P<0.01) and stemflow (4.5 vs. 5.8, respectively; P<0.01). Runoff occupied only 0.3% of the gross rainfall in P. elliottii stand and was zero in L. molleoides stand. Our results showed that the native species L. molleoides presented 13.6% more water reaching the topsoil (i.e., net rainfall; net rainfall=gross rainfall-interception-runoff) than the exotic species P. elliottii. This study improves our understanding of the effects of native vegetation replacement on the local water balance in the dry forest ecosystems.     

Combined nitrogen input from legume residues and fertilizer improves early nitrogen supply and uptake by wheat

Soil nitrogen (N) supply for wheat N uptake can be manipulated through legume and fertilizer N inputs to achieve yield potential in low‐rainfall sandy soil environments. Field experiments over 2 years (2015–2016) were conducted at 2 different sites in a low‐rainfall sandy soil to determine the soil N supply capacity relative to wheat N uptake at key growth stages, after a combination of crop residue (removed, wheat or lupin) and fertilizer N (nil, low or high N) treatments were manipulated to improve wheat yield. We measured the temporal patterns of the soil profile mineral N and PAW to 100 cm depth, wheat aerial biomass and N uptake in both years. In 2016 we also measured the disease incidence as a key environmental variable. There was 35 kg ha^?1 more soil mineral N to 100 cm depth following lupin than wheat residues at the end of the fallow on average in both years. In a below average rainfall season, wheat biomass produced on lupin residues was responsive to N input with soil profile mineral N depleted by increased crop N uptake early in the season. In an above average rainfall season, a higher soil mineral N supply increased actual and potential grain yield, total biomass, N uptake, harvest index and water use efficiency of wheat, regardless of the source of N. Our study showed that the combination of lupin residues with high N rate increased soil profile mineral N at early growth stages, providing a greater soil N supply at the time of high wheat N demand, and the inclusion of a legume in the rotation is critical for improving the N supply to wheat, with added disease break benefits in a low‐rainfall sandy soil environment.