盐度对哈氏仿对虾肌肉一般营养成分和氨基酸组成及含量的影响

通过调查不同盐度(12～36)环境下养殖的哈氏仿对虾(Parapenaeopsis hardwickii)肌肉一般营养成分和氨基酸组成及含量,研究了盐度对该虾肌肉营养品质的影响。结果显示,肌肉的水分随环境盐度升高出现显著的直线下降,而粗蛋白含量随环境盐度升高而直线升高;各盐度组的粗脂肪含量虽然没有明显差异,但其含量随盐度升高有一定的线性下降趋势;36盐度组的粗灰分含量比12、16、20和28盐度组的明显高,32盐度组的灰分含量比20和24盐度组的也明显高;所检测的肌肉干样16种氨基酸中,只有3种氨基酸的含量随盐度升高而升高,而其他13种氨基酸的含量随盐度升高明显降低,其中有10种氨基酸的含量在盐度12～24条件下的比盐度28～36条件下的明显高,而这些氨基酸含量在盐度12～24之间没有明显差异。各盐度组间氨基酸总量和鲜味氨基酸含量均没有明显差异;必需氨基酸和半必需氨基酸含量在盐度12～24条件下的均比盐度28～36条件下的明显高,而在12～24盐度组之间以及28～36盐度组之间均没有明显差异。必需氨基酸/氨基酸总量的比值和必需氨基酸/非必需氨基酸比值随盐度升高均明显线性降低;盐度12～24组的必需氨基酸指数(66.13～67.42)高于盐度28～36组的(62.56～64.46)。综上所述,盐度12～24环境下养殖的哈氏仿对虾肌肉营养价值相对较高,表现为低盐趋向,考虑到肌肉的水分含量和生长性能,哈氏仿对虾在养殖期间选择16～24盐度范围比较合适,同时也说明哈氏仿对虾适合大多数沿海地区环境的盐度条件。     

花生品种耐盐性指标筛选与综合评价

采用盆栽试验,设置不同盐胁迫浓度,通过萌发至幼苗期的出苗速度、植株形态和生物量等指标对200个花生品种(系)进行耐盐性评价.结果表明: 随盐胁迫浓度的增加,花生出苗时间延长,对植株形态建成抑制加重,物质积累减少.鉴定花生品种耐盐性强弱的适宜盐胁迫浓度为0.30%~0.45%.采用隶属函数值法将10个指标归结为平均隶属函数值,根据不同胁迫浓度下各指标与平均隶属函数值之间的相关性大小,植株鲜质量、地上部鲜质量、地下部鲜质量、地下部干质量、株高和主茎高均较大,可作为首选指标,植株干质量、地上部干质量、主根长和出苗速率均较小,可作为辅助指标综合判断品种的耐盐能力.200个品种(系)在不同盐胁迫浓度下均可分成高度耐盐型、耐盐型、盐敏感型和高度盐敏感型4组.随盐胁迫强度加大,耐盐品种数量下降,而盐敏感品种数量上升.部分品种在低、中、高盐胁迫强度下表现出统一性(均耐盐或均敏感);部分品种存在差异性,即低胁迫强度下表现耐盐性而在高胁迫强度下表现盐敏感性.     

Characteristics of bacteria showing high denitrification activity in saline wastewater

AIMS: Denitrification efficiency at 10% salinity was compared with that at 2% salinity. The characteristics of bacterial strains isolated from the denitrification system, where an improvement of denitrification efficiency was observed at a high salinity were investigated. METHODS AND RESULTS: Two continuous feeding denitrification systems for saline solutions of 2% and 10% salinity, were operated. Denitrification efficiency at 10% salinity was higher than that at 2% salinity. The bacterial strains were isolated using the trypticase soy agar (TSA) medium at 30 degrees C. The phylogenetic analysis of 16S rRNA gene sequences of isolates indicated that halophilic species were predominant at 10% salinity. CONCLUSIONS: The improvement of denitrification efficiency at a high salinity was demonstrated. The strains isolated from the denitrifying system with 10% salinity were halophilic bacteria, Halomonas sp. and Marinobacter sp., suggesting that these bacteria show a high denitrifying activity at 10% salinity. SIGNIFICANCE AND IMPACT OF THE STUDY: The long-term acclimated sludge used in this study resulted in high denitrification performance at a high salinity, indicating that the design of a high-performance denitrification system for saline wastewater will be possible.     

Implication of nutrient and salinity interaction on the productivity of <Emphasis Type="Italic">Spartina patens</Emphasis>

Reintroduction of fresh water to coastal systems with altered hydrologic regimes is a management option for restoring degraded wetland habitats. Plant production in these systems is believed to be enhanced by increased nutrient availability and reduced salinity. Although studies have documented nutrient limitation and salinity stress in coastal marshes, interpreting the effects of freshwater reintroduction on plant production is difficult because high nutrient availability often is confounded with low salinity. We tested the hypothesis that plant growth response to nutrients does not vary with salinity in a greenhouse study. Treatments consisted of four nutrient concentrations and four non-lethal salinity levels; plant response was measured as biomass accumulation after 144 days of exposure. The significant interaction between salinity and nutrient concentrations indicates that response of Spartina patens marshes to freshwater inflows would vary by site-specific soil conditions. Biomass decreased with increased salinity at all four nutrient concentrations with variation among the nutrient concentrations decreasing as salinity increased. We demonstrate the importance of considering ambient salinity and nutrient soil conditions in restoration planning involving freshwater inflow. We propose salinity should remain a primary concern in restoration plans targeted at improving degraded S. patens-dominated marsh habitat.     

红树植物秋茄和海莲幼苗过氧化物酶对栽培盐度条件的反应

本文探讨了系列海水盐度砂培的红树植物秋茄和海莲幼苗叶片、根尖的过氧化物酶活性及其同工酶对不同盐度条件的反应。结果表明：(1)秋茄苗：在低盐度0‰至10‰范围,叶过氧化物酶活性随盐度提高而略有增强,15‰以上则降低;根尖过氧化物酶活性则不同,随盐度(0—35‰)提高而降低。(2)海莲苗：随其生长基盐度(5—25‰)提高,叶过氧化物酶活性迅速降低,而根尖过氧化物酶活性在5‰至10‰盐度时略有提高,15‰以上迅速降低;而后高盐度(25一35‰)活性降低不明显。这表明,在盐度的影响下,秋茄苗过氧化物酶活性变化程度小而海莲大。(3)在同工酶谱表现上,两种植物幼苗(叶,根)均为主级酶带受盐度影响不明显,但次级酶带对盐度敏感。     

Mangrove Seedling Net Photosynthesis,Growth, and Survivorship are Interactively Affected by Salinity and Light1

We hypothesized that salinity and light interactively affect mangroves, such that net photosynthesis, growth, and survivorship rates increase more with increase in light availability at low than high salinity. Using greenhouse and field experiments, we determined that net photosynthesis, growth rates, and size increased more with light at low than high salinity. At high salinity, the ratio of leaf respiration to assimilation increased fourfold, suggesting that salinity may have contributed to declines in net photosynthesis. Stomatal conductance, leaf‐level transpiration, and internal CO₂ concentrations were lower at high salinity. Ratios of root mass to leaf mass were higher at high salinity. Stomatal limitations and increased respiratory costs may explain why at high salinity, the seedlings did not respond to increased light availability with increased net photosynthesis. Increased root mass relative to leaf mass suggests that at high salinity, either water or nutrient limitations may have prevented the seedlings from increasing growth with increasing light availability. At both low‐ and high‐salinity zones in the field, seedling survivorship increased with light availability, and the effect of light was stronger at low salinity. However, at low light, survivorship was higher at high than low salinity, indicating that there may be a trade‐off between survivorship and growth. The interactive effects observed in the greenhouse were robust in the field, despite the presence of other factors in the field such as inundation and nutrient gradients and herbivory. This study provides a robust test of the hypothesis that salinity and light interactively effect mangrove seedling performance.     

Salinity as a determinant of salt lake fauna: a question of scale

High and often variable salinity is an obvious feature of salt lakes. Correspondingly, salinity is usually assumed to be an important ecological determinant in such lakes. An investigation of the macroinvertebrate fauna of 79 lakes (salinities from 0.3 to 343 g 1^–1) in the Western District of Victoria, Australia, examined this assumption. Over the total range of salinity, species richness and composition are highly correlated with salinity. However, these relationships become nonsignificant over intermediate ranges of salinity. Furthermore, many taxa have very broad tolerances to salinity at these intermediate ranges, implying that factors other than salinity may determine their distribution. An appreciation of scale (that is, the range of salinity over which observations are considered) resolves the paradox that, despite these broad tolerances by most taxa, species richness and composition strongly reflect salinity over the entire salinity range.     

花生苗期耐盐性评价及耐盐指标筛选

评价鉴选耐盐品种对于盐碱地花生生产具有重要意义。采用盆栽试验,设置不同盐胁迫浓度,对200个花生品种(系)萌发至幼苗期通过出苗速度、植株形态和生物量等指标进行耐盐性系统评价。结果表明,随盐胁迫浓度的增加,出苗时间延长,植株形态建成抑制加重,物质积累减少。鉴选花生品种耐盐性强弱的适宜盐胁迫浓度为0.30%—0.45%,超过此浓度不能出苗。地上部形态和生物量可作为耐盐评价的首选指标,主根长和出苗速度可作为辅助指标用以判断花生品种的综合耐盐能力。200个品种(系)在不同盐胁迫浓度下均可分成高度耐盐型、耐盐型、盐敏感型和高度盐敏感型4组。耐盐品种数量随盐胁迫强度加大而下降,盐敏感品种数量则上升。0.15%浓度下200个品种全部出苗,4个类型品种数分别占供试材料的29.0%、39.0%、27.5%和4.5%;0.30%浓度下185个品种出苗,4个类型品种数分别占供试材料的5.5%、34.5%、23.5%和29.0%;0.45%浓度下107个品种出苗,4个类型品种数分别占供试材料的5.5%、5.5%、20.0%和22.5%。14个品种在各盐浓度胁迫下均表现耐性,10个品种在各盐浓度胁迫下均表现敏感,为花生耐盐机理研究及生产应用提供了不同类型材料。     

Interaction Effects of Citrus Rootstocks, Salinity and Tylenchulus semipenetrans Parasitism on Osmotically Active Ions

High densities of Tylenchulus semipenetrans and slow decline symptoms are dominant in citrus-producing areas with high salinity. Currently, no commercial citrus rootstock is both nematode-resistant and salt-tolerant. Interaction effects of citrus rootstocks, salinity and T. semipenetrans were evaluated for the partitioning of salinity ions (Cl and Na) and K in microplots. Treatments comprised six citrus rootstocks with wide ranges of salt tolerance, 0 and 3 mols NaCl + 0.25 mols CaCl₂ l⁻¹ water and 0 and 856 300 nematodes. At harvest, eight months after salinity treatments, the three–factor interaction was significant (P=0.05) for the alteration in the partitioning of salinity ions and K. Nematodes generally increased salinity ions in leaves and reduced salinity ions in roots and K in both leaves and roots. Thus, management of nematodes is critical in areas with salinity problems.     

Relationship of water transport to anatomical features in the mangrove Laguncularia racemosa grown under contrasting salinities

The purpose of this study was to investigate the xylem anatomy and hydraulic characteristics of the mangrove Laguncularia racemosa grown under contrasting salinities. The study addressed the hypothesis that, at high salinity, water transport capacity may decrease in association with higher water use efficiency. Plants were grown in media to which 0, 15 and 30 NaCl was added. Vessel density and diameter were determined in transverse sections of stem and midrib leaves in terminal shoots, and hydraulic parameters were measured. In stems, the vessel density increased with salinity, while the anatomical diameter (d(a)) and hydraulic diameter (d(h)) declined; in leaves, these parameters remained unchanged with salinity. Huber value and hydraulic and specific conductivities decreased with salinity. Leaf blade resistance increased with salinity and represented the largest fraction of twig resistance. Xylem anatomy and leaf tissue of L. racemosa appeared to be modulated by salinity, which led to a coordinated decline in hydraulic properties as salinity increased. Therefore, these structural changes would reflect functional water use characteristics of leaves under salinity.     

土壤盐度对加拿利海枣幼苗生长与生理指标的影响

将加拿利海枣(Phoenix canariensis Hort. ex Chab.)幼苗培养在不同盐度(1.2~14.5)的土壤中,探讨土壤含盐量对其生长及生理指标的影响。结果表明:随基质盐度的提高,幼苗新生叶片数降低且叶片死亡数增加。随基质盐度的提高,叶绿素含量增加,叶绿素a/b在低盐度时增加而当盐度超过5.1时下降。土壤盐度在1.2~5.1时,MDA含量约为4.30 μmol g^-1,以后随土壤盐度的升高而升高。SOD活性在低盐时升高,土壤盐度超过10.8时,SOD活性迅速下降。盐胁迫下叶片Na⁺和Cl^-含量升高,K⁺、Ca²⁺、Mg²⁺含量及K⁺/Na⁺下降。盐胁迫导致加拿利海枣生长下降的主要原因是叶片有效光合面积减少,离子平衡破坏。这些表明加拿利海枣具有很高的耐盐能力,其幼苗在土壤盐度5.1时生长正常,当土壤盐度为10.8时才开始出现受害症状,适宜在滨海地区推广应用。     

Responses to low salinity by the sea star Pisaster ochraceus from high‐ and low‐salinity populations

Abstract. In many coastal environments, variation in salinity and organismal responses to that variation are important determinants of the distribution and abundance of species. This study examined the effects of acute salinity changes on sea stars (Pisaster ochraceus) collected from a high‐salinity site (Bamfield, BC) and a low‐salinity site (Vancouver, BC). Sea stars from both sites were exposed to salinities ranging 15–30 psu. Following a 24‐h exposure, the osmolality, sodium concentrations, and chloride concentrations in the perivisceral fluid all varied directly with salinity and were very close to the treatment salinities in both the Bamfield and Vancouver sea stars. The righting response (measured as an activity coefficient) was salinity dependent, with the lowest activity levels at a salinity of 15 psu. Activity coefficients did not vary between the two source populations. Feeding rates on mussels were strongly salinity dependent, but the salinity pattern was population specific. Bamfield sea stars fed the most at 30 psu, whereas Vancouver sea stars fed the most at 20 psu. High post‐experimental mortalities were observed in Bamfield sea stars that had been exposed to a salinity of 15 psu; no such mortality was observed in Vancouver animals. This study provides evidence that the sea stars from the lower salinity environment had been able to acclimatize or adapt to low‐salinity conditions. However, the results also suggest that there are limits to this tolerance, and that future changes in salinity may have important consequences for marine communities via alteration of keystone predation.     

不同生境条件下中国柽柳空间分布点格局分析

通过聚类分析方法将黄河三角洲中国柽柳的生境划分为三种类型,即高盐干旱型生境,低盐干旱型生境和低盐湿润型生境;同时运用点格局分析方法,分析了不同生境中中国柽柳在不同尺度下空间分布规律,结果表明,高盐干旱和低盐干旱生境中龄级2的中国柽柳以及低盐湿润生境中龄级3的中国柽柳在所有尺度范围内都呈随机分布,而其它龄级在不同生境的空间分布规律具有较显著差异,说明黄河三角洲低龄级和高龄级中国柽柳能够通过调整空间分布模式来适应适应水盐平衡变化等生态过程;不同生境中的中国柽柳各龄级之间关系在不同尺度内呈正相关概率要大于呈负相关概率,个别尺度上某些龄级之间没有相关性.     

CYST–THECA RELATIONSHIP,LIFE CYCLE,AND EFFECTS OF TEMPERATURE AND SALINITY ON THE CYST MORPHOLOGY OF GONYAULAX BALTICA SP. NOV. (DINOPHYCEAE) FROM THE BALTIC SEA AREA1

A new species of Gonyaulax, here named Gonyaulax baltica sp. nov., has been isolated from sediment samples from the southeastern Baltic. Culture strains were established from individually isolated cysts, and cyst formation was induced in a nitrogen‐depleted medium. Although G. baltica cysts are similar to some forms attributed to Spiniferites bulloideus and the motile stage of G. baltica has affinities with G. spinifera, the combination of features of cyst and motile stage of G. baltica is unique. The culture strains were able to grow at salinity levels from 5 to 55 psu and formed cysts from 10 to 50 psu. Cultures at each salinity level were grown at 12, 16, and 20° C. Temperature‐ and salinity‐controlled morphological variability was found in the resting cysts. Central body size varied with temperature and salinity, and process length varied with salinity. Cysts that formed at extreme salinity levels displayed lower average process length than cysts formed at intermediate salinity levels, and central body length and width were lowest at higher temperature and lower salinity. Models for the relationship between central body size and temperature/salinity and process length and salinity have been developed and may be used to determine relative paleosalinity and paleotemperature levels. Our results on salinity‐dependent process length confirm earlier reports on short‐spined cysts of this species found in low salinity environments, and the model makes it possible to attempt to quantify past salinity levels.     

Effects of salinity on O₂ consumption, ROS generation and oxidative stress status of gill mitochondria of the mud crab Scylla serrata

Mitochondrial respiration, activities of electron transport chain enzymes and formation of oxidative stress parameters were investigated in mitochondria isolated from gill tissue of mud crabs (Scylla serrata) as a function of salinity (10 ppt, 17 ppt and 35 ppt). Mitochondrial oxygen consumption rate was higher for succinate as substrate compared with those of glutamate, malate and pyruvate. Complex I and complex II mediated respirations were higher at low salinity (10 ppt) than high salinity (17 ppt and 35 ppt). Although activities of electron transport chain enzymes particularly complexes I (EC 1.6.5.3), II (EC 1.3.99.1) and II-III (EC 1.3.2.1) were elevated linearly in response to salinity treatment, activity of complex V (ATPase, EC 3.6.1.34) was decreased at 35 ppt salinity. However, ATPase activity was higher at 17 ppt salinity in comparison to 10 ppt and 17 ppt salinity. Results of the experiment suggest that high salinity (35 ppt) causes hypoxic state in mitochondria of mud crabs. Hypoxic condition induced by high salinity was accompanied with increased hydrogen peroxide production resulting oxidative stress in mitochondria of crabs. A possible mechanism of hypoxia-induced reactive oxygen species generation and OS due to salinity stress in the crabs is discussed.     

Chlorophyll a biomass and growth of sea-ice microalgae along a salinity gradient (southeastern Hudson Bay,Canadian Arctic)

Summary The biomass of microalgae at the bottom of first-year sea ice, in southeastern Hudson Bay (Canadian Arctic), parallels an inshore-offshore salinity gradient caused by the under-ice plume of the Great Whale River. The present study was designed to test the hypothesis that the variation of ice-algal biomass (chlorophyll a) along the salinity gradient was mainly controlled by nutrient availability, with the alternative hypothesis of a direct control by ambient salinity. The approach was that of differential in situ bioassays, conducted at the ice-water interface of two stations, located in the plume of the Great Whale River (lower salinity) and in the offshore waters of Hudson Bay (higher salinity). The inoculum (collected at the higher salinity station) was diluted with three types of seawater, i.e. (1) from the higher salinity station, (2) from the lower salinity station, and (3) from the latter but with salinity artificially increased to the level of the higher salinity station. The three sets of cultures were differentially enriched. In situ incubations for the first set were at the higher salinity station and, for the other two, at the lower salinity station. Results indicate possible Si limitation of the algal biomass at the higher salinity station. First, concentrations of Si(OH)₄ observed at this station were lower than in the plume of the Great Whale River; in addition, the SiP molar ratios were lower than ca. 15; also, Si was the only nutrient whose addition (alone or combined with others) yielded biomasses higher than in the reference enrichment; finally, the highest growth rate for a singly added nutrient was with Si and subtraction of Si (single nutrient) was more detrimental to growth rate than that of N or P. In contrast, there was no strong indication of nutrient effects at the lower salinity station, so that nutrient limitation could not explain the lower ice-algal biomasses in lower salinity waters. At this same station, on the other hand, growth rates in water with artificially increased salinity were 2–3 times higher than those in unaltered water. These results are consistent with the hypothesis that salinity, and not nutrients, is the main factor that limits the development of ice algae in the lower salinity waters of southeastern Hudson Bay.Contribution to the programs of GIROQ (Groupe interuniversitaire de recherches océanographiques du Québec) and of the Maurice Lamontagne Institute (Biological Oceanography Division, Department of Fisheries and Oceans)     

Salinity and light interactively affect neotropical mangrove seedlings at the leaf and whole plant levels

We have studied the interactive effects of salinity and light on Avicennia germinans mangrove seedlings in greenhouse and field experiments. We hypothesized that net photosynthesis, growth, and survivorship rates should increase more with an increase in light availability for plants growing at low salinity than for those growing at high salinity. This hypothesis was supported by our results for net photosynthesis and growth. Net daily photosynthesis did increase more with increasing light for low-salinity plants than for high-salinity plants. Stomatal conductance, leaf-level transpiration, and internal CO₂ concentrations were lower at high than at low salinity. At high light, the ratio of leaf respiration to assimilation was 2.5 times greater at high than at low salinity. Stomatal limitations and increased respiratory costs may explain why, at high salinity, seedlings did not respond to increased light availability with increased net photosynthesis. Seedling mass and growth rates increased more with increasing light availability at low than at high salinity. Ratios of root mass to leaf mass were higher at high salinity, suggesting that either water or nutrient limitations may have limited seedling growth at high salinity in response to increasing light. The interactive effects of salinity and light on seedling size and growth rates observed in the greenhouse were robust in the field, despite the presence of other factors in the field—such as inundation, nutrient gradients, and herbivory. In the field, seedling survivorship was higher at low than at high salinity and increased with light availability. Interestingly, the positive effect of light on seedling survivorship was stronger at high salinity, indicating that growth and survivorship rates are decoupled. In general, this study demonstrates that environmental effects at the leaf-level also influence whole plant growth in mangroves.     

Growth and chemical composition of dry beans as affected by soil salinity and N fertilization

Summary The effects of three levels of N (0, 50 and 100 ppm) and four salinity regimes (0.5, 1.5, 2.5 and 3.5 mmhos/cm) on the growth and mineral composition of dry beans (Phaseolus vulgaris L.) were investigated in a greenhouse experiment. Bean plants treated with N produced more dry weight and contained higher N than the untreated check. Growth and N uptake by bean plants generally decreased with increasing irrigation water salinity at all N levels. High salinity caused severe burning of the margins of older leaves and stunting of growth. At the low salinity levels (0.5 and 1.5 mmhos/cm), N additions had no effect on growth; however, the suppressing effects of higher salinity were alleviated somewhat with N fertilization.The concentration and uptake of Cl and Na increased with increasing salinity; probably the relatively high accumulations of Cl and Na were responsible for growth reductions at high salinity.     

不同盐度预处理后Ⅰ龄暗纹东方鲀的摄食、生长和饲料利用

通过4周的生长实验,研究了Ⅰ龄暗纹东方(8235±297g)在不同盐度预处理后的摄食、生长和饲料利用情况。结果显示:35‰的预处理盐度对暗纹东方的生长有抑制作用,当这种盐度胁迫解除后,暗纹东方的生长表现出明显的补偿现象。本实验中摄食率随前处理盐度的升高而增加,变化范围为183%-251%,特定生长率亦随前处理盐度增加而增加,即由083%增加到128%,饵料系数则随前期盐度实验中盐度的增加而降低,由167降至147。在盐度预处理实验及淡化养殖条件下的特定生长率除8‰外有显著差异。       

Salinity tolerance in different life history stages of an invasive false mussel Mytilopsis sallei Recluz, 1849: implications for its restricted distribution

ABSTRACT

Although the false mussel Mytilopsis sallei Recluz, 1849 is recognised as an aggressive invasive species, its populations in several estuaries in Thailand are restricted to small areas. A salinity gradient is a major characteristic of its habitat, hence the effect of various salinity levels (0–40?ppt) on the mortality of larvae, juveniles and adults of M. sallei was investigated. Condition Indices of adults reared at different salinity levels for two months were measured. Spatial and temporal variations of salinity and false mussel abundance in a canal with a salinity gradient were also monitored. After an acute (48?h) test, survival of larvae was highest at salinity levels of 12.5 and 16.25?ppt and decreased at lower and higher levels. Juveniles survived at all salinity levels, but most adults died in the first 24?h at a salinity of 40?ppt, while condition indices were lowest at salinity levels of 30 and 35?ppt. In the field survey, highest false mussel abundance was consistently found at the middle part of the canal with mid-range salinity. The results suggested that salinity is a determinant of survival in M. sallei larvae and potentially regulates the dispersal success of false mussels. However, the importance of salinity was marginal in the later stages of its life history.