Characteristics of plant calcium fractions for 25 species in Tengger Desert

Little attention has been paid to plant calcium fractions in the desert.To address the characteristic of the calcium fractions of desert plants,we collected 25 plant species in Tengger Desert,observed the calcium crystals using an optical microscope and determined water soluble calcium,acetic acid soluble calcium,and hydrochloric acid soluble calcium.To do so,we used sequential fractionation procedures to probe the relationships among different functional groups,different growth forms,or different successional stages.The results showed that the psammophyte,the late successional plants,and the drought-resistant shrub and semi-shrub all held considerable calcium oxalate crystal compared to the grassland plants,the early successional plants,and the perennial herb.With the proceeding succession,the acetic acid soluble calcium decreased gradually,and the hydrochloric acid soluble calcium increased gradually.The perennial herb had more water soluble calcium,while shrub held greater hydrochloric acid soluble calcium.The grassland plants held more water soluble calcium,while psammophyte had greater hydrochloric acid soluble calcium.This implies that the plants that are relatively sensitive to drought hold more calcium ion,while the drought-resistance plants hold more calcium oxalate.Thus,the plant calcium components are in close relation to plant drought-resistance,and of important significance in plant physiology of the desert.     

Addition of Phosphorus and Nitrogen Support the Invasiveness of Alternanthera Philoxeroides Under Water Stress

Coordination of plant functional traits with changes in the environment is helpful to understand the mechanisms underlying both invasiveness and adaptation of plants. Thus, to investigate the performance and functional traits in invasive Alternanthera philoxeroides (Mart.), an experiment of water stress is conducted with different nutrient concentrations. Alternanthera philoxeroides plants are grown under natural and nutrient soils and subjected to three levels of nitrogen (N) and phosphorus (P) solution: ambient P and N concentration (P?N?), P addition with an ambient N concentration (P+N?), and P addition with high N concentration (P+N+) in combination with three different irrigation water levels as 1) 100% irrigation, 2) 50% irrigation, and 3) 25% deficit irrigation. Based on results, A. philoxeroides produces significantly higher biomass in both soils under 100% irrigation with P+N? treatment and exhibits higher values of leaf area and root length. However, 25% irrigation with P?N? treatment in both soils exerts a significant negative effect on relative growth rate and root/shoot ratio of A. philoxeroides plants. Under 50% irrigation in soils with both P+N? and P+N+ treatments, high values of leaf nitrogen are recorded. Moreover, nutrient soil is more supportive to A. philoxeroides than natural soil.     

Metabolic activity throughout early development of dusky kob Argyrosomus japonicus (Sciaenidae)

The physiology of fishes in the early stages of development remains poorly assessed despite the importance of identifying energy bottlenecks in organisms faced with changing environmental conditions. This study describes the metabolic activity of dusky kob Argyrosomus japonicus throughout its early development, from hatchling to settlement stage. Standard, routine and active metabolic rates (SMR, RMR and AMR, respectively) were assessed to determine the species’ metabolic scope and identify how metabolism changes with growth and development. Distinct metabolic changes occurred in association with developmental changes during the early life stages, with flexion-stage larvae showing significantly reduced metabolic scope (approx. 0.30 µmol O₂ ind.^–1 h^–1), representing an energy bottleneck. Based on these findings, it is likely that larvae of A. japonicus are most susceptible to environmental perturbations during flexion. The variability of metabolic rates during the diel cycle was also assessed and revealed that the early-stage larvae showed no preference for daylight, although settlement-stage juveniles were more active during daylight hours (RMR = 12.78 µmol O₂ ind.^–1 h^–1) than at night (RMR = 5.87 µmol O₂ ind.^–1 h^–1). These results suggest that metabolic measurements of the SMR of A. japonicus larvae can be taken at any time of the diel cycle until the settlement phase, when readings should take place at night.     

异养营养对丛生盔形珊瑚代谢及共生藻光合生理的影响

本文以三亚鹿回头近岸海域内的优势种造礁石珊瑚——丛生盔形珊瑚(Galaxea fascicularis)为研究对象,以丰年虾(Artemia salina)无节幼体为饵料,研究了异养营养对丛生盔形珊瑚光合作用与呼吸代谢的影响。结果表明:异养营养的输入能够增加丛生盔形珊瑚的共生虫黄藻密度以及色素含量,并能够显著提升其光合作用与呼吸速率,然而单个虫黄藻的光合速率降低,这与虫黄藻密度增加引起的遮蔽效应有关。从营养角度来看,异养营养的输入能够使丛生盔形珊瑚有机碳的净积累速率提升约44.5%。本研究结果显示异养营养的输入能够促进丛生盔形珊瑚的光合与呼吸代谢,且这种情况下丛生盔形珊瑚的营养模式更为健康。     

差异蛋白质组学在水产动物环境生理学中的研究进展

随着蛋白质组学技术的发展,差异蛋白质组学的研究已引起国内外学者的广泛关注.差异蛋白质组学主要通过寻找、筛选和鉴定由某些因素引起的样本之间的差异蛋白质谱,揭示生物机体生理和病理过程以及对外界环境刺激的反应途径和调控机制,同时获得对某些关键蛋白的定性和功能分析,从分子水平上解析更多的生命现象本质.本文着重介绍了差异蛋白质组学在凝胶和非凝胶技术方面的最新技术方法,综述了差异蛋白质组学在水产动物养殖环境生理学与环境毒理学方面的研究进展,为从蛋白质水平上解析水产动物生理调控机制提供了技术支撑.     

Determination of element composition of three lichens and their distribution in King George Island, Antarctica

Cross-section slices of Usnea antarctica Du Rietz, Usnea aurantiaco-atra (Jacq.) Bory. and Cladonia sp. at upper, middle and basal positions were prepared, respectively. The element composition and relative content were determined by SEM and EDS at the surface, intermediate and inner layers in each slice, respectively. The result indicated that the composition of element is mostly same in these lichens. The relative content of Al, Si, K and Ca elements is high, and P is close at each position. The result is of benefit to study the structure and physiological characteristics of lichens, and to analyze geological environment in Antarctica.     

Age and hydrological significance of lichen limits on sandstone river channels near Sydney,Australia

Trimmed lichen communities (lichen limits) are abrupt changes from a lichen community to a scoured bare rock surface and have been used to determine bankfull channel capacity on bedrock channels and their response to the combined disturbances of flow regulation and climate change. They can also be used to set flushing flows in bedrock channels. In sandstone gorges of the Nepean River, Australia, the crustose lichen, Lecidea terrena Nyl, was common at both gorge and cemetery (sandstone headstones) sites, enabling construction of growth curves for above and below dam areas. Growth curves were used to date lichen colonisation of sandstone surfaces in rivers. The oldest, highest lichen limit at all sites represented the pre‐flow regulation lichen community because its characteristics above and below Nepean Dam were similar and were trimmed to a level that produced consistent discharges across a range of catchment areas. They corresponded to return periods of less than 2 years on the annual maximum series and was developed during the flood‐dominated regime (FDR) of 1857–1900. Lichen limits form by the phycobiont dominating the mycobiont and hence degrading lichen thalli due to water inundation causing weak or dead thalli to be scrubbed from the rock surface. Trimming to the unregulated lichen limit represents a small flood of frequent occurrence appropriate for flushing bedrock channels. A lower lichen limit was only found below a diversion weir and was formed by frequent dam spills between 1950 and 1952 during an extraordinary wet period at the start of the FDR between 1949 and 1990. Lichens colonised exposed sandstone between the level of frequent flows from 1949 to 1952, and the high lichen limit. On the Avon River, an additional lower limit reflected a massive downward shift in flow duration following the start of interbasin diversions to Wollongong in 1962.     

栽培羊栖菜(Sargassum fusiforme)成熟藻体不同器官的组织结构显微观察及其生理生态学功能剖析

为全面了解栽培羊栖菜(Sargassum fusiforme)成熟藻体假根、茎、叶(气囊)和生殖托(雌托和雄托)四类器官的组织形态特征,运用石蜡切片法,对栽培羊栖菜成熟藻体各器官进行了组织形态学观察和讨论分析。结果表明,不同器官横切组织的形态、结构和宽度差异显著;假根,茎,叶,雌、雄生殖托的横切面由外向内分别为表皮、近表皮、皮层和髓部组织,而气囊无髓部组织结构,但具有内皮层。此外,雌、雄生殖托还包括生殖窝、卵和精子结构。栽培羊栖菜各器官表皮细胞均呈栅栏状排列,宽度顺序为:雄生殖托茎雌生殖托气囊叶假根;表皮和近表皮细胞含淀粉粒最多,内含色素体;皮层和髓部细胞的淀粉粒含量相对较少;皮层组织的细胞腔最大,具有典型植物细胞形态和发达的胞间隙;髓部细胞致密,细胞腔多数较小。有关文献报道表明,羊栖菜不同器官响应光照、水温、干出与沉水及低盐胁迫等环境信号表达的生理生态学特征差异显著。研究结果可为深度解析栽培羊栖菜各器官之间的亚细胞结构差异,不同器官生理代谢响应环境信号表达差异,不同器官组织对微量元素或重金属离子的吸收、转运和储藏机制分析等研究提供基础数据和理论参考。