In vivo localization of manganese in the hyperaccumulator Gossia bidwillii (Benth.) N. Snow & Guymer (Myrtaceae) by cryo-SEM/EDAX

Gossia bidwillii (Myrtaceae) is a manganese (Mn)-hyperaccumulating tree native to subtropical eastern Australia. It typically contains foliar Mn levels in excess of 1% dry weight. However, in G. bidwillii and other Mn-hyperaccumulating species, the cellular and subcellular localization of Mn has not been measured. Quantitative in vivo cryo-scanning electron microscopy (SEM)/energy dispersive X-ray analysis (EDAX) was used to localize Mn and other elements in tissue collected from mature trees growing in a natural population. Cryo-SEM showed that the leaf mesophyll is differentiated as a double-layer palisade mesophyll above spongy mesophyll. Transmission electron microscopy (TEM) revealed that the palisade and epidermal cells are highly vacuolated. EDAX data were used to estimate in situ vacuolar Mn concentrations of all cell types in fresh cryo-fixed leaf tissues. The highest average vacuolar Mn concentration of over 500 mM was found in the upper-layer palisade mesophyll, while the lowest concentration of around 100 mM was found in the spongy mesophyll. Qualitative in vivo cryo-SEM/EDAX was employed to further investigate the spatial distribution of Mn in fresh leaf tissues and young bark tissue, which was also found to have a high Mn concentration. It is concluded that Mn distribution in G. bidwillii is quantitatively different to metal distribution in other hyperaccumulating species where the highest localized concentrations of these elements occur in non-photosynthmetic tissues such as epidermal cells and associated dermal structures including trichomes and leaf hairs.     

Variability of Mn hyperaccumulation in the Australian rainforest tree Gossia bidwillii (Myrtaceae)

This study examines the heterogeneity of the Mn-hyperaccumulative trait in natural stands of the Australian rainforest tree species Gossia bidwillii (Myrtaceae). It is the only known Mn hyperaccumulator from Australia, and has an unusual spatial distribution of Mn in its leaves. G. bidwillii occurs naturally on a range of Mn-containing substrates including ultramafic soils. Leaf samples were collected from individual trees and four small stands, over a longitudinal range of ∼600 km. While no variation in the spatial distribution of foliar Mn was detected, considerable variation in Mn concentration was found. G. bidwillii was shown to accumulate Mn when growing on a variety of substrates, and dry weight (DW) foliar Mn concentrations of all trees sampled ranged between 2,740 and 27,470 μg g⁻¹. The majority of samples exceeded 10,000 μg g⁻¹, the threshold value for Mn hyperaccumulation. The overall frequency distribution of foliar Mn concentration was found to be bimodal, with a small outlier of extreme hyperaccumulators. Highest values were obtained from trees growing on a basaltic krasnozem clay, not ultramafic soil. Soil Mn concentrations were measured, and no relationship was found between foliar Mn concentrations and extractable Mn concentrations in host substrates. Some of the variation in the Mn-hyperaccumulative trait in G. bidwillii throughout its large natural distribution may reflect the unresolved taxonomy of this most widespread species in the genus Gossia. Ability to hyperaccumulate Mn may serve as an additional diagnostic tool for resolving this taxonomy.     

Manganese accumulation in the leaf mesophyll of four tree species: a PIXE/EDAX localization study

Little is known about the spatial distribution of excess manganese (Mn) in the leaves of tolerant plants. Recently, the first such study of a Mn hyperaccumulator showed that the highest localized Mn concentrations occur in the photosynthetic tissue. This is in contrast to reports based on localization of foliar accumulation of other heavy metals. Here, four tree species, Gossia bidwillii, Virotia neurophylla, Macadamia integrifolia and Macadamia tetraphylla, which hyperaccumulate or strongly accumulate Mn, were studied. Cross-sectional foliar Mn localization was carried out in situ using proton-induced X-ray emission/energy dispersive X-ray analysis (PIXE/EDAX). All four species contained photosynthetic tissues with multiple palisade layers. These were shown to be the primary sequestration sites for Mn. Mn was not detected in the epidermal tissues. The findings of this study demonstrate a concurrence of three traits in four tree species, that is, accumulation of excess Mn in the leaves, its primary sequestration in the photosynthetic tissues, and multiple-layer palisade mesophyll.     

Foliar nutrient allocation patterns in Banksia attenuata and Banksia sessilis differing in growth rate and adaptation to low-phosphorus habitats

Background and AimsPhosphorus (P) and nitrogen (N) are essential nutrients that frequently limit primary productivity in terrestrial ecosystems. Efficient use of these nutrients is important for plants growing in nutrient-poor environments. Plants generally reduce foliar P concentration in response to low soil P availability. We aimed to assess ecophysiological mechanisms and adaptive strategies for efficient use of P in Banksia attenuata (Proteaceae), naturally occurring on deep sand, and B. sessilis, occurring on shallow sand over laterite or limestone, by comparing the allocation of P among foliar P fractions.MethodsWe carried out pot experiments with slow-growing B. attenuata, which resprouts after fire, and faster growing opportunistic B. sessilis, which is killed by fire, on substrates with different P availability using a randomized complete block design. We measured leaf P and N concentrations, photosynthesis, leaf mass per area, relative growth rate and P allocated to major biochemical fractions in B. attenuata and B. sessilis.Key ResultsThe two species had similarly low foliar total P concentrations, but distinct patterns of P allocation to P-containing fractions. The foliar total N concentration of B. sessilis was greater than that of B. attenuata on all substrates. The foliar total P and N concentrations in both species decreased with decreasing P availability. The relative growth rate of both species was positively correlated with concentrations of both foliar nucleic acid P and total N, but there was no correlation with other P fractions. Faster growing B. sessilis allocated more P to nucleic acids than B. attenuata did, but other fractions were similar.ConclusionsThe nutrient allocation patterns in faster growing opportunistic B. sessilis and slower growing B. attenuata revealed different strategies in response to soil P availability which matched their contrasting growth strategy.     

Characteristics of foliar chemistry in a commerical spruce-fir stand of northern New England,USA

Monthly foliage samples were evaluated for elemental composition from red spruce and balsam fir trees in a commercial, low elevation spruce-fir stand at Howland, Maine during the 1987 growing season. Balsam fir showed consistently higher concentrations in A1 and to a lesser extent N, Ca, Mg, and Fe when compared to red spruce. Red spruce exhibited consistently higher Mn and K concentrations. Both species showed a marked seasonal trend in the foliar concentrations of N, P, K, and Ca in current year foliage. For N, P, and K current year foliar concentrations declined rapidly during the early part of the growing season. Calcium concentrations steadily increased during the growing season for both species and age class of needles. Foliar concentrations of N and P in both species suggests that the availability of these nutrients is limited for this site.     

Growth and physiological responses of trembling aspen (Populus tremuloides), white spruce (Picea glauca) and tamarack (Larix laricina) seedlings to root zone pH

Background and aims

Soil pH is among the major environmental factors affecting plant growth. Although the optimum range of soil pH for growth and the tolerance of pH extremes widely vary among plant species, the pH tolerance mechanisms in plants are still poorly understood. In this study, possible mechanisms were examined to explain the differences in tolerance of boreal plants to root zone pH.

Methods

In the controlled-environment solution culture experiments, we compared growth, physiological parameters and tissue nutrient concentrations in aspen, white spruce and tamarack seedlings that were subjected to 8 weeks of root zone pH treatments ranging from 5.0 to 9.0.

Results

The pH treatments had little effect on dry weights and net photosynthesis in white spruce seedlings despite reductions in transpiration rates at higher pH levels. In aspen and tamarack, both the growth and physiological parameters significantly decreased at pH higher than 6.0. The chlorosis of young tissues in aspen and tamarack was associated with the reductions in foliar concentrations of several of the examined essential nutrients including Fe and Mn. Although the plants varied in their ability to deliver essential nutrients to growing leaves, there was no direct correlation between tissue nutrient concentrations, chlorophyll concentrations and plant growth. The results also demonstrated strong inhibition of transpiration rates by high pH.

Conclusions

The results suggest that high root zone pH can upset water balance in pH sensitive species including aspen. Although the uptake and assimilation of essential elements such as Fe and Mn contribute to plant tolerance of high soil pH, we did not observe a direct relationship between growth and foliar nutrient concentrations to account for the observed differences in growth.     

Foliar and wood chemistry of sugar maple along a gradient of soil acidity and stand health

The decline of sugar maple (Acer saccharum Marsh.) in forest of north-eastern North America is an important environmental issue. In this study, relationships between, soil, wood and foliar chemistry were assessed for 17 stands distributed within a large area of the Quebec sugar maple forest and that were growing on soils with a strong gradient of acidity and base saturation. There were many significant relationships between variables describing the acid-base status of the top-B soil (Ca and Mg concentrations, exchangeable acidity and base saturation) and Ca and Mn concentrations and Ca/Mn and Mg/Mn in tree tissues. Manganese was the element that showed the strongest inverse non-linear relationships with top-B soil base saturation with variance explanation of 71 and 65%, for wood and foliage, respectively. The 17 sites were divided in two groups according to their level of decline. The declining stands had significantly higher wood Mn and Mg concentrations and lower Ca/Mn ratios and significantly higher foliar Mn and lower Ca and Al concentrations. It was impossible to determine if these differences were a cause or a symptom of sugar maple health. However, the increase in Mn concentrations in tree tissues with increasing soil acidity, as well as the higher Mn concentrations in declining as compared to healthy stands suggest that Mn, as well as low Ca availability, could be an important contributing factor in the sugar maple decline.     

东北羊草草地锰、铜、锌含量特征的研究

 本文研究了羊草(Aneurolepidium chinense)草地割草场3种植物必需的微量元素锰、铜、锌的含量特征。结果表明,在生长季各时期,优势种羊草各器官元素含量有很大变化,总的趋势是：根>根茎>茎>叶>穗(Zn：叶>茎),各器官之间元素含量差异显著(P<0.05)。其它种类植物根中锰、铜、锌含量也显著高于地上各器官。羊草地上部锰、铜、锌积累量在生长季中的变化近似于“S”型曲线,但各元素曲线最高点出现的时间不同。寸草苔(Carex duriuscula)和针蔺(Heleocharis acicularis)地上部锰、铜、锌积累量变化与生物量变化相似,基本为双峰型曲线。三种元素在群落中的分布规律是：根>茎>叶>穗,与生物量分布规律相同。但锰、铜在地上各器宫中积累量占植物总积累量的比率低于相应的生物量比率,而锌这两者的比率则与生物量比率相近。群落中锰、铜、锌积累量与根层土壤中锰、铜、锌总量之比分别为0.10%,0.33%和0.09%。     

长白山林线主要木本植物叶片养分的季节动态及回收效率

植物叶片养分含量的季节动态和回收效率对植被生态系统的养分循环和植物生长策略具有重要意义。以长白山高山林线上分布的3种主要木本植物——岳桦(Betula ermanii),牛皮杜鹃(Rhododendron aureum)和笃斯越橘(Vaccinium uliginosum)为研究对象,通过测定叶片中N、P、K、Ca、Mg、Fe等6种养分元素含量,分析在林线处植物叶片养分含量的季节动态及其与土壤养分含量的关系。结果表明岳桦和笃斯越橘叶片中养分元素的季节动态基本一致,即:N、P、K含量在生长季内逐渐降低,而Ca的含量逐渐增加;Mg在生长季旺盛期最低,而Fe含量却最高。牛皮杜鹃作为常绿灌木,叶片养分的季节动态与其余两种植物明显不同,表现为在生长季初期6种养分元素含量最低。岳桦和笃斯越橘植物叶片中N、P、K、Fe都有一定程度的回收,但笃斯越橘叶片的养分回收率更高,反映了笃斯越橘更能适应相对贫瘠的环境。3种林线植物叶片中养分含量与土壤养分并不存在显著的相关性,说明长白山林线上土壤中养分的分布没有对林线上3种主要的木本植物的生长和分布产生直接的影响。     

The absorption and transport of manganese by perennial ryegrass and white clover as affected by silicon

Summary The effects of added silicon on the absorption and transport of manganese in perennial ryegrass (an accumulator of Si) were determined and compared with those found in white clover (which has restricted Si uptake). The plants were grown in flowing solution culture in two experiments with Si in the nutrient solution maintained at 0, 10 or 20 mgl⁻¹ and Mn at 0.005 mgl⁻¹. By the final harvests, the plants contained concentrations of both Mn and Si that were comparable to those found in field-grown plants. In common with other findings, white clover had very much lower concentrations of Si in both shoots and roots than did ryegrass but there was no effect of Si treatment on the growth of either species. In both species, the concentrations of Mn were initially greater in roots than in shoots, but values in both plant parts decreased with time and by the final harvests, were similar. The rates of absorption of Mn by roots and its subsequent transport to shoots were also similar in both species. In contrast to findings for other species in other studies based on conventional solution culture, there was no effect of added Si on either absorption or transport of Mn in clover or ryegrass. It was therefore concluded that any effect of Si on the behaviour of Mn in plants must result from changes in distribution and partitioning within leaf tissues and cells.     

Soil influence on Cu and Co uptake and plant size in the cuprophytes Crepidorhopalon perennis and C. tenuis (Scrophulariaceae) in SC Africa

Cuprophytes are plants that mostly occur on Cu-rich soil in SC Africa. Crepidorhopalon perennis is endemic of a single site. C. tenuis has a broader niche, from normal to Cu-rich soil. Both have been considered as Cu-Co accumulators. We examined soil factors controlling heavy metal accumulation and plant fitness in natural populations. Plant mass and element concentrations in plants and soil were determined in 153 samples from five populations of C. tenuis on copper soil (CTC), two on normal soil (CTN) and the single population of C. perennis (CP). Soil in Cu-sites had higher concentrations of Ca, Mg, P, Mn, Zn, Cu, Co. Plants from Cu-sites were larger and had higher Cu and Co content, and lower Mg, Mn and Ca. Cu in shoots was influenced positively by Cu and Mn and negatively by Ca in the soil. Co in shoots was influenced positively by Co and negatively by Mn and Fe in the soil. Shoot mass was influenced positively by Cu and Mn (CT) or by Cu and Co (both species pooled) in the soil. The results suggest that C. tenuis and C. perennis are genuinely cuprophilous species. Large variation in metal accumulation in shoots can be accounted for by synergistic and antagonistic interactions among several heavy metals, yielding specific accumulation patterns in different populations.     

The resurrection flowering plant Ramonda nathaliae on serpentine soil – coping with extreme mineral element stress

Ramonda nathaliae (Gesneriaceae) is a rare desiccation tolerant flowering plant species of the Northern Hemisphere. This, mainly calcicole, preglacial relict species is endemic in the Balkan Peninsula, where it has survived in its refugial habitats of gorges and mountain slopes. At present, only two localities within its narrow range are known where it thrives in hostile serpentine habitats, and the adverse serpentine environment is bound to present further challenge to the adaptive capacity of R. nathaliae. In general, the occurrence of a resurrection flowering plant on serpentine soil is exceptional and the soil-plant relation of R. nathaliae in those circumstances is described here for the first time. The aim of this study was (i) to analyze mineral elements composition in soil from both serpentine and limestone habitats of the species and to compare the way peculiarities of the substrates are reflected in roots and leaves of plants from the respective soils; (ii) to evaluate the effect of heavy metal overload on the habit of serpentine R. nathaliae individuals. Serpentine soil, characterized by high levels of phytotoxic heavy metals (Ni, Cr, Co, Mn), hosts plants showing elevated metal contents in their organs. Ramonda plants from serpentine populations are able to maintain balance of Ca to Mg favourable to Ca (2.0 in roots, 2.7 in leaves) despite a strongly unfavourable Ca/Mg ratio in the soil (0.09). The greatest difference in concentrations was observed for the Ni content in plant tissues: serpentine plants had 57 and 20 times more Ni in their roots and leaves than the plants from limestone. Aluminium was present in similar concentrations in both soils, and was highly accumulated in plant tissues of the plants from both substrates. Metal-specific metabolic activity is demonstrated in bioaccumulation indices of several essential minerals (Ca, Mg, Cu, Zn). A significantly higher metal content found in roots in relation to leaves might indicate the plant's ability to immobilize the metals within the root tissues. Mycorrhizal fungi colonize plant roots from both substrates and apparently are important in improving the supply of nutrients, but they could also take part in toxic metal immobilization. The price of adaptation to the hostile environment is evident in the habit of R. nathaliae plants growing on serpentine: reduced size of rosettes and leaves, as well as chlorotic and necrotic leaf tips and margins.     

Ultrastructure of the integumental melanophores of the South American lungfish (Lepidosiren paradoxa) and the African lungfish (Protopterus sp.)

The integumental melanophores of two genera of lungfish, Lepidosiren paradoxa and Protopterus sp. were examined by light and electron microscopy. Both species possess both epidermal and dermal melanophores with fine structural characteristics basically similar to those of other vertebrates. The epidermal melanophores of both species are located in the intermediate epidermis, and possess thin perikarya containing round nuclei, and slender dendrites extending into the nearby intercellular spaces. The dermal melanophores occur immediately beneath the basement membrane, and possess flat perikarya and dendrites running horizontally between the collagen fibers of the dermis. The integument of both species does not possess an epidermal melanin unit or a dermal chromatophore unit. As in other vertebrates, each melanophore contains numerous oval, electron-opaque melanosomes, relatively large mitochondria, vacuolar endoplasmic reticula, and groups of RNP particles. Although micro filaments running randomly between other organelles occur regularly, microtubules were not demonstrated. Premelanosomes at various stages of differentiation were best illustrated in the dermal melanophores of Protopterus, and it is concluded from the observation of their fine structure that the morphological development of lungfish melanosomes closely parallels that of higher vertebrates. On the basis of melanophore morphology, Lepidosiren and Protopterus appear to be more closely related to each other than to Neoceratodus.     

Intraspecific variation and plasticity in growth and foliar morphology along a climate gradient in the Canary Island pine

Foliar plasticity in response to ontogeny, location within the plant and environmental changes is widespread among long-lived organisms. To quantify the phenotypic variation in needle morphology and anatomy in response to a climate gradient, we compared contrasted populations of Pinus canariensis grown in five sites inside and outside the natural distribution area of the species. Most needle and growth traits were strongly affected by site. In general, site xericity increased the relative area of the dermal and transfusion tissues and decreased mesophyll and endodermis. Within each site, provenances from less productive locations tended to show longer needles, less relative area of dermal tissues but higher relative area of mesophyll and transfusion tissue than provenances from fertile origins. Although sclerophylly increased with aridity, no genetic differences were found for this trait thus apparently the ontogenetic delay of some provenances in xeric environments was not related with the formation of tougher needles. Several patterns of phenotypic response to different environments were shown. In general, all traits were plastic but the degree of plasticity was higher in traits related with growth than foliar traits. These results, combined with formerly published research, suggest that highly plastic populations rather than narrowly specialized ones have been selected in this species to cope with the complex interaction of environmental factors in its habitat.     

Habitat‐specific differences in plasticity of foliar δ13C in temperate steppe grasses

A decrease in foliar δ¹³C with increasing precipitation is a common tendency in steppe plants. However, the rate of decrease has been reported to differ between different species or populations. We here hypothesized that plant populations in the same habitat of temperate steppes may not differ in foliar δ¹³C response patterns to precipitation, but could differ in the levels of plasticity of foliar δ¹³C across different habitats. In order to test this hypothesis, we conducted controlled watering experiments in northeast China at five sites along a west–east transect at latitude 44°N, which show substantial interannual fluctuations and intra‐annual changes in precipitation among them. In 2001, watering treatment (six levels, three replicates) was assigned to 18 plots at each site. The responses of foliar δ¹³C to precipitation (i.e., the sum of watering and rainfall) were determined in populations of several grass species that were common across all sites. Although similar linear regression slopes were observed for populations of different species growing at the same site, significantly different slopes were obtained for populations of the same species growing at different sites. Further, the slope of the line progressively decreased from Site I to Site V for all species in this study. These results suggest habitat‐specific differences in plasticity of foliar δ¹³C in temperate steppe grasses. This indicates that species' δ¹³C response to precipitation is conservative at the same site due to their long‐term acclimation, but the mechanism responsible behind this needs further investigations.     

不同季节亚热带常绿阔叶林6个树种凋落叶钙、镁、锰的释放特征

采用凋落物分解袋法,研究了亚热带常绿阔叶林区马尾松、柳杉、杉木、香樟、红椿、麻栎6个典型树种凋落叶的Ca、Mg、Mn在第一个分解年不同雨热季节的释放特征.结果表明：经历1年的分解,6种凋落叶Ca、Mg、Mn释放率分别为-13.8%～92.3%、4.0%～64.8%和41.6%～81.1%.马尾松和香樟凋落叶Ca释放动态呈现富集-释放模式,其余4种凋落叶整体上呈现释放的模式;香樟凋落叶Mg释放动态呈现富集-释放模式,其余5种凋落叶呈现直接释放模式;柳杉和红椿凋落叶Mn释放动态呈现富集-释放模式,其余4种凋落叶呈现直接释放模式.凋落叶Ca、Mg、Mn的释放明显受到季节性降雨的影响,且因凋落叶种类不同而有差异.Ca、Mg、Mn在雨季的释放率和释放量均高于旱季.初始养分含量和降雨量是影响凋落物分解过程元素释放的重要因子.     

Genotypic differences in manganese efficiency: field experiments with␣winter barley (Hordeum vulgare L.)

Eight different winter barley genotypes were grown in a plot experiment in northern Denmark, on soil where Mn deficiency had been previously demonstrated, to assess field performance and grain yield under two treatments: with foliar Mn fertilisation and without foliar Mn fertilisation. A high Mn efficiency was demonstrated for two of the genotypes and a low Mn efficiency was observed for one of the genotypes in three consecutive years; highly variable results were obtained for other genotypes. Mn efficiency based on grain yields could not be related to whole shoot Mn concentration, biomass or Mn uptake at various vegetative growth stages. Chlorophyll a fluorescence analysis was able to differentiate between the two Mn treatments up to 7weeks after the last Mn application, whereas Mn concentrations, shoot biomass and Mn accumulation could not. It was not possible to fully alleviate Mn deficiency by repeated foliar spraying on the control plots. Given the growing conditions at the trial site and the low Mn in plant tissue, it is possible that Mn deficiency was extreme enough that Mn efficiency mechanisms broke down.     

Diurnal patterns of gas‐exchange and metabolic pools in tundra plants during three phases of the arctic growing season

Arctic tundra plant communities are subject to a short growing season that is the primary period in which carbon is sequestered for growth and survival. This period is often characterized by 24‐h photoperiods for several months a year. To compensate for the short growing season tundra plants may extend their carbon uptake capacity on a diurnal basis, but whether this is true remains unknown. Here, we examined in situ diurnal patterns of physiological activity and foliar metabolites during the early, mid, and late growing season in seven arctic species under light‐saturated conditions. We found clear diurnal patterns in photosynthesis and respiration, with midday peaks and midnight lulls indicative of circadian regulation. Diurnal patterns in foliar metabolite concentrations were less distinct between the species and across seasons, suggesting that metabolic pools are likely governed by proximate external factors. This understanding of diurnal physiology will also enhance the parameterization of process‐based models, which will aid in better predicting future carbon dynamics for the tundra. This becomes even more critical considering the rapid changes that are occurring circumpolarly that are altering plant community structure, function, and ultimately regional and global carbon budgets.     

Effects of nitrogen and water addition on trace element stoichiometry in five grassland species

A 9-year manipulative experiment with nitrogen (N) and water addition, simulating increasing N deposition and changing precipitation regime, was conducted to investigate the bioavailability of trace elements, iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in soil, and their uptake by plants under the two environmental change factors in a semi-arid grassland of Inner Mongolia. We measured concentrations of trace elements in soil and in foliage of five common herbaceous species including 3 forbs and 2 grasses. In addition, bioaccumulation factors (BAF, the ratio of the chemical concentration in the organism and the chemical concentration in the growth substrate) and foliar Fe:Mn ratio in each plant was calculated. Our results showed that soil available Fe, Mn and Cu concentrations increased under N addition and were negatively correlated with both soil pH and cation exchange capacity. Water addition partly counteracted the positive effects of N addition on available trace element concentrations in the soil. Foliar Mn, Cu and Zn concentrations increased but Fe concentration decreased with N addition, resulting in foliar elemental imbalances among Fe and other selected trace elements. Water addition alleviated the effect of N addition. Forbs are more likely to suffer from Mn toxicity and Fe deficiency than grass species, indicating more sensitivity to changing elemental bioavailability in soil. Our results suggested that soil acidification due to N deposition may accelerate trace element cycling and lead to elemental imbalance in soil–plant systems of semi-arid grasslands and these impacts of N deposition on semi-arid grasslands were affected by water addition. These findings indicate an important role for soil trace elements in maintaining ecosystem functions associated with atmospheric N deposition and changing precipitation regimes in the future.     

Exploring nanoscale structure change of dermal tissues suffering injury by small angle X-ray scattering and transmission electron microscopy

Scar formation and wound non-healing often occur during wound repair after skin injury, which are still unresolved. Clinic indicated that the structure played an important role in the wound repair. Our previous research showed that the wound over-healed (scar formation) when the integrity and continuity of dermal tissues was destroyed by injury. Other evidences showed that wound healing was impaired in diabetes because the underlying alternation in their skin tissues occurred caused by advanced glycation end products (AGES) aggregation. In order to explore the changes of the structure of skin at nanoscale, the small angle X-ray scattering (SAXS), compared with transmission electron microscopy (TEM), was applied to observe the skin in different pathological status. The results showed that there were some regular patterns in the structure of dermal tissue. The patterns were changed by different pathological status, which would result in wound healing disorder. These will be beneficial for clarifying the pathological mechanisms of wound healing.