NaCl胁迫下沙枣幼苗的离子代谢特性

[Objective]To further understand the ion metabolism characteristics of Elaeagnus angustifolia L. under NaCl stress.[Method]The seedlings of two E. angustifolia L. provenances, which were Alaer (salt tolerance provenance) and Yinchuan (salt sensitive provenance), were treated by three NaCl concentrations (0,150,300 mmol·L^-1) and sampled at the 7th day and the 30th day to measure the Na⁺ , K⁺, Ca²⁺, and Mg²⁺ contents, K⁺/Na⁺ ratio and selective absorption and transportation of K⁺ in tissues (roots, stems and leaves). [Result]The results showed that the Na⁺ content in the organizations of E. angustifolia L. sharply increased with the increase of NaCl concentration. With prolonging of stress time, the Na⁺ content increased in roots, and decreased in stems and leaves. After seedlings of the two provenances were treated with 150 mmol·L^-1 NaCl for 7 days, the Na⁺ content was 2.10 times and 2.23 times in leaves, respectively, compared with the control groups, and was 1.79 times and 1.57 times in root. Meanwhile, the difference between two provenances showed a expanding trend with the increase of NaCl concentration and stress time. With the increase of NaCl concentration and extension of stress time, the K⁺ content, Ca²⁺ content and K⁺/Na⁺ ratio in organizations decreased gradually. Meanwhile, the Alaer provenance seedlings accumulated more Na⁺ in roots and less Na⁺ in leaves than that of Yinchuan provenance, and the K⁺ content, Ca²⁺ content and K⁺/Na⁺ ratio decreased less in the Alaer provenance seedlings than those of Yinchuan provenance. With the increase of NaCl concentration, the Mg²⁺ content in leaf gradually decrease, but the Mg²⁺ content in root increased 22.8~64.4% after salt stress for 7 days, and Alaer provenance seedlings increased more than Yinchuan provenance. After 30 days, there was non-significant difference with the control group on the Mg²⁺ content of root. K⁺ selective absorption of E. angustifolia L. seedlings significantly increased with increasing salt concentration of the media at the 7th days, whereas not obvious at the 30th days. When the concentration of NaCl in the media increased, the change of K⁺ selective transportation was not significant. [Conclusion]E. angustifolia L. seedlings increase Mg²⁺ content and K⁺ selective absorption in the roots at the early stage of salt stress to adapt saline environment. The salt-tolerance E. angustifolia L. provenance can cut off more Na⁺ in roots and reduce Na⁺ content in leaves, which cause less K⁺, Ca²⁺ and Mg²⁺ contents loss, especially the roots and leaves, so as to ensure that all kinds of metabolisms can go well.     

Change in river water chemistry as affected by the confluence of forest drainage water in dairy farming area on Hokkaido Island, Northern Japan

We evaluated i) the difference in river water chemistry between a watershed mainly consisting of pasture and a watershed mainly consisting of forest, and ii) how the chemistry of river draining the pasture is influenced by that of the river draining the forest. We selected one river (designated as the T-river) draining the pasture (3,587 ha), and two rivers draining a forest (738 and 879 ha) in eastern Hokkaido, northern Japan. During higher river flow due to precipitation and thawing, the concentrations of NO ₃ ⁻ , SO ₄ ²⁻ , K⁺, Fe, and Al increased, suggesting the relative importance of the shallow soil layer as their source. On the other hand, Na⁺, Mg²⁺, Ca²⁺, and Si decreased, suggesting the relative importance of the source in a deep soil layer. The concentrations of NO ₃ ⁻ , Cl⁻, SO ₄ ²⁻ , K⁺, Na⁺, Mg²⁺, Ca²⁺, and Fe were higher in the T-river than in the forest drainage waters, suggesting the contribution of the excretion components from the milk cows. The Si concentration exhibited the opposite pattern. The concentrations of NO ₃ ⁻ , Cl⁻, SO ₄ ²⁻ , K⁺, Na⁺, Mg²⁺, Ca²⁺ (p<0.001), and Fe (p<0.05) in the T-river decreased after the confluence of the forest drainage waters, while Si concentration increased (p<0.001). The reason for the change in river chemistry was the confluence of the forest drainage waters. These findings suggested the environmental role of the forest in the dilution of the polluted river. Prof. S. Ohata, and Prof. H. Takeda, Graduate School of Agriculture, Kyoto University, facilitated this study. Prof. T. Sakai, Graduate School of Informatics, Kyoto University, offered this study some convenience. Dr. M. Sakimoto, and Dr. M. Katsuyama, Graduate School of Agriculture, Kyoto University, offered useful advise.     

短期NaCl胁迫对西伯利亚白刺幼苗Na~+、K~+分配和平衡的影响

[目的]为探究西伯利亚白刺盐适应机制。[方法]以1年生西伯利亚白刺水培幼苗为材料,研究不同浓度NaCl(0、200、300 mmol·L-1)胁迫24 h后根系Na~+、K~+离子流的动态变化(利用扫描离子选择微电极技术,SIET)及植株各器官中Na~+、K~+含量的静态变化(利用电感耦合等离子体光谱仪,ICP-OES)。[结果]表明:(1)短期NaCl胁迫显著提高了西伯利亚白刺根、茎、叶中Na~+含量,其中,叶中Na~+含量是根中的3倍以上;西伯利亚白刺根、茎、叶中K~+含量保持稳定或上升;(2)盐胁迫下,西伯利亚白刺根、茎、叶中K~+/Na~+呈下降趋势,其中,在200、300 mmol·L-1NaCl胁迫下,根中K~+/Na~+差异不显著;(3)离子流结果显示,NaCl胁迫显著提高了西伯利亚白刺根系Na~+的外流;对照和200 mmol·L-1NaCl胁迫下,K~+净流量分别为156、159 pmol·cm-2·s-1,差异不显著;300 mmol·L-1NaCl胁迫显著提高了K~+的内流,净流量为-370 pmol·cm-2·s-1。[结论]综合分析认为,西伯利亚白刺通过叶片对Na~+区隔,加强根系对Na~+的外排和K~+内流,进而维持植株根系K~+/Na~+的相对平衡,以此适应盐渍环境。     

Canopy leaching of subtropical mixed forests under acid rain

Leaching of major ions from acid precipitation in a subtropical forest was examined based on an experiment in four sample sites in Shaoshan City, Hunan Province, China, from January 2001 to June 2002. Results clearly show that when rain passed through the canopy, pH increased and the evidence of ion uptake was presented for SO₄ ²⁻, NO₃ ⁻, Mg²⁺ and NH₄ ⁺ ions, especially of NH₄ ⁺ and NO₃ ⁻. The percentages of dissolved SO₄ ²⁻, Ca²⁺ and Mg²⁺ show a decreasing trend with increasing rainfall. Percentages of leaching Ca²⁺, K⁺ and Cl⁻ ions show an increasing trend as a function of increased pH values. The forest canopy in Shaoshan City has a strong effect on the uptake of SO₄ ²⁻ and NO₃ ⁻ ions under acid rain conditions. The decreasing order of ions leaching in the forest canopy is as follows: K⁺ > Ca²⁺ > Cl⁻ > Mg²⁺ > SO₄ ²⁻ > NO₃ ⁻ > NH₄ ⁺ > Na⁺. __________ Translated from Scientia Silvae Sinicae, 2007, 43(7): 1–4 [译自: 林业科学]     

Transfer characteristics of nutrient elements through hydrological process of a Pinus tabulaeformis stand in the West Mountain of Beijing

Forest precipitation chemistry is a major issue in forest hydrology and forest ecology. Chemical contents in precipitation change significantly when different kinds of external chemical materials are added, removed, translocated and transformed to or in the forest ecosystem along with precipitation. The chemistry of precipitation was monitored and analyzed in a 31-year-old Pinus tabulaeformis forest in the West Mountain of Beijing. Movement patterns of nutrient elements in hydrological processes can be discovered by studying this monitored data. Also, the information is useful for diagnosing the function of ecosystems and evaluating the impact of the environment on the ecosystem. Samples of rainfall, throughfall and stemflow were collected on the site. In the lab, Ca²⁺ and Mg²⁺ were analyzed by flame atomic absorption and K⁺ and Na⁺ by flame emission. NH₄ ⁺-N was analyzed by indophenol blue colorimetry and NO₃ ⁻-N was analyzed by phenoldisulfonic acid colorimetry. The results showed that: 1) The concentration gradient of nutrient elements clearly changed except for Na⁺. The nutrients in stemflow were significantly higher than those of throughfall and rainfall as the precipitation passed through the P. tabulaeformis forest. The monthly patterns showed distinct differentiation. There are indications that a large amount of nutrients was leached from the canopy, which is a critical function of intra-ecosystem nutrient cycling to improve the efficiency of nutrient use. 2) The concentrations of NO₃ ⁻-N and K⁺ changed more than those of the other nutrient elements. The concentration of NO₃ ⁻-N in throughfall and stemflow was 4.4 times and 9.9 times higher than those in rainfall, respectively. The concentration of K⁺ in throughfall and stemflow was 4.1 times and 8.1 times higher than those in rainfall, respectively. 3) The leaching of nutrient elements from the stand was an important aspect of nutrient return to the P. tabulaeformis forest, which returned a total amount of nutrient of 54.1 kg/hm², with the contribution of Ca²⁺ and K⁺ much greater than that of other elements. Also, K⁺ was the most active element in leaching intensity. 4) Nutrient input through precipitation was the main source in the West Mountain of Beijing and the amount of nutrient added was 66.4 kg/hm², of which Ca²⁺ and N contributed much more than the other nutrient elements. When precipitation passes through the P. tabulaeformis forest, 121 kg/hm² of nutrient is added to the forest floor. Ca²⁺ recorded the greatest nutrient increase, with 61.2 kg/hm², followed by N (NH₄ ⁺-N and NO₃ ⁻-N), K⁺ and Mg²⁺, with 31.3 and 16.5, and 8.11 kg/hm², respectively. The least was Na⁺, 3.34 kg/hm². Translated from Acta Ecologica Sinica, 2006, 26(7): 2,101–2,107 [译自: 生态学报]     

Evaluation of the inorganic compound leakage and carbohydrates as indicator of physiological potential of <Emphasis Type="Italic">Ulmus parvifolia</Emphasis> seeds

Inorganic compound leakage and change of carbohydrate were measured in Ulmus parvifolia seeds throughout accelerated aging under 35°C and 75% relative humidity (RH) to investigate whether these indicators can be used as a rapid vigor test for efficient seed bank management. Accelerated aging seeds treated for 0–14 days exhibited loss of germinability in the longest aging treated seeds (11%, 14 days) compared to a good performance of 52% for control (0 day) seeds. Leachate electrical conductivity (EC) increase had strong negative correlation with seed vigor (−0.9). Magnesium ion concentration in electrolyte leakage from artificial aged seeds showed positive correlation (r = 0.94, P < 0.01). The ratios of inorganic ions showed that K⁺/Mg²⁺, Ca²⁺/Mg²⁺, and Na⁺/Mg²⁺ were inversely correlated with germination (−0.93, −0.82, and −0.91, respectively). Increases in starch and total soluble sugar content in aged seeds were associated with a decrease in seed vigor. In conclusion, EC, magnesium ion concentration, K⁺/Mg²⁺, Ca²⁺/Mg²⁺, and Na⁺/Mg²⁺ ratios and starch and total soluble sugar content could provide a sensitive and accurate index for the assessment of U. parvifolia seed vigor.     

Effect of NaCl on growth and ion relations in two salt-tolerant strains of Paxillus involutus

The effect of NaCl on growth, biomass and ion relations of two salt-tolerant isolates of Paxillus involutus, MAJ and NAU were investigated. The two Paxillus strains were exposed to the following concentrations of NaCl： 0, 100, 200 and 500 mmol·L^-1. Growth of MAJ and NAU was enhanced by 100 mmol·L^-1 NaCl but severely inhibited at the concentration of 500 mmol·L^-1. NAU exhibited a greater capacity to exclude Na^＋ and Cl^- under all salinity levels, whereas the salt-includer MAJ had a higher capacity in nutrient uptake under salt stress. The ratios Na^＋/K^＋, Na^＋/Ca^2＋ and Na^＋/Mg^2＋ in NaCl-treated MAJ and NAU did not increase at levels of 100 and 200 mmol·L^-1 NaCl but markedly increased at 500 mmol·L^-1. This suggests that the two strains, especially MAJ, enhanced nutrient uptake corresponding to the increased Na^＋ influx at moderate salinity. We conclude that both MAJ and NAU are able to tolerate 500 mmol·L^-1 NaCl but there are species-specific differences in retaining ionic homeostasis in the two Paxillus strains. NAU is a salt-excluder, MAJ is a salt-includer but retains a high capacity in nutrient selectivity under saline conditions. Their definite mechanisms to enhance salt tolerance of mycorrhizal hosts need further study.     

Cytochemical localization of H+-ATPase and sub-cellular variation in mesophyll cells of salt-treated Cyclocarya paliurus seedlings

Cyclocarya paliurus seedlings of three provenances were treated with three levels of salt (0, 51.0 and 85.0 mmol/L NaCl) in a hydroponic system of a phytotron. The ultrastructural distribution of H⁺-ATPase activity and ultrastructural variation were investigated in mesophyll cells of C. paliurus seedlings after 12 or 20 days of salt treatment. The results showed that under normal growing conditions, H⁺-ATPase activity was low and localized mainly in the nucleus. After 12 days of salt treatment and an increase in salinity, we found that the greater the H⁺-ATPase activity, the lighter the damage suffered by mesophyll subcells after 20 days of salt treatment and the stronger the salt-adaptation ability of seedlings. The location of H⁺-ATPase, largely in the nucleus, indicated that salt-damage suffered by the seedlings was light, whereas its presence, mainly in the vacuoles, showed that salt-damage was more serious. Our preliminary conclusion is that the salt-tolerance level of C. paliurus seedlings for the three kinds of provenances was in the following order, from high to low: Huangshan seedlings from Anhui Province > Kunming seedlings from Yunnan Province > Jiujiang seedlings from Jiangxi Province.     

Water quality of Kaptai reservoir in Chittagong Hill Tracts of Bangladesh

A study was conducted in Kaptai reservoir, one of the largest man-made freshwater lakes of South-east Asia, to determine present status of water quality and its suitability for fishing and other uses. Water samplings were from middle part of the reservoir at 0.2 and 0.8 fractional depths at five different locations from upstream to downstream viz. Burburichara, Maichchari, Subolong, Basanthakum, and Rangamati. Water analyses show that concentrations of NO3-N, K+ and total P, and suspended solid at all the sampling stations were beyond the recommended values for fish culture. Concentrations of Na+, Ca2+, Mg2+, SO42-, Cl-, total dissolved solid (TDS), dissolved oxygen (DO) and chemical oxygen demand (COD) were within the standards for aquaculture. Concentrations of NO3-N, SO42-, K+ and total P showed no definite trend with depths, locations as well as rainy and dry seasons. Water pH, conductivity, Na+ and HCO3- contents were lower in rainy season, and DO and COD higher at almost all the locations in both the depths, compared with dry season. Total solids and concentrations of TDS, DO, COD, Ca2+, Mg2+ and Na+ were higher in upstream and decreased gradually towards downstream in the reservoir. Concentrations of DO and Ca2+ and pH were higher and Mg2+ less at 0.2-fractional depth than those at 0.8-fractional depth at almost all the locations. The reservoir is in mesotrophic condition containing high concentration of NO3-N and total P, in alarming status with the presence of excessive suspended solids from urban pollution around the town. It is necessary to adopt measures for protecting water quality in the reservoir due to such deteriorations.     

Relationship between streamflow and nutrient and sediment losses from an oak-beech forest watershed during an 18-year long monitoring study in Turkey

The objectives of this study were to quantify the amount of the stream discharge, nutrient fluxes, suspended sediment loss, and to define the relationship between streamflow and these parameters in a forest-covered watershed. The study was carried out in an experimental watershed, which has been monitored since 1979 in the Belgrad forest in Istanbul. Significant linear regressions were obtained between streamflow and discharge of selected water quality parameters. Mean monthly losses were 10.01 kg/ha for HCO₃ ⁻, 5.92 kg/ha for CI⁻, 0.07 kg/ha for total N, 1.29 kg/ha for Mg²⁺, 3.59 kg/ha for Ca²⁺, 2.59 kg/ha for Na⁺, 1.82 kg/ha for K⁺, 0.0113 kg/ha for P-PO₄ ³⁻, and 35.82 kg/ha for suspended sediments. Among the monitored water quality parameters, HCO₃ ⁻, CI⁻, and Ca²⁺ had greater losses than the rest of the chemical parameters studied in the watershed. Net gains (influx exceeded outflux) calculated for total N, Mg²⁺, K⁺, and P-PO₄ ³⁻ in the annual basis can be considered as an addition to the ecosystem’s organic nutrient pool. In contrast, net losses occurred for HCO₃ ⁻, CI⁻, Ca²⁺, and Na⁺.     

Effects of Ca^2＋concentrations on accumulations of mineral elements in the components of Pteroceltis tatarinowii

The bark ofPteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca²⁺ concentrations on the accumulation of mineral elements in the bark, leaf and root ofPteroceltis tatarinowii were studied under controlled conditions. The types of Hoagland nutrient solution with three Ca²⁺ concentrations levels (200, 400 and 600 μg·g⁻¹) and a control (without Ca²⁺ were designed to culturePteroceltis tatarinowii. After 6 months, contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and bark were analyzed. The results indicated that Ca accumulations content in the root, leaf and bark had positively relation with Ca²⁺ concentrations (200, 400, 600 μg·g⁻¹), and the order of the Ca content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g⁻¹ Ca²⁺ concentrations was 5.5 times as high as that of the control, and about 1.4 times as high as that of the root treated in 200 and 400 μg/g Ca²⁺ concentrations respectively. On the contrary, K and Mg contents in the root, leaf and bark were negatively related to Ca²⁺ concentrations, especially in the bark, and their accumulation trend followed the order of leaf>root>bark. K content in the bark treated with 600 μg·g⁻¹ Ca²⁺ concentrations was 39.3% of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200μg·g⁻¹ and 400μg·g⁻¹ Ca²⁺ concentrations respectively; Mg content in the bark treated with 600μg·g⁻¹ Ca²⁺ concentrations was 23.4% of that of the control, and was 27.1% and 35.4% of that of the bark treated with 200 and 400 μg·g⁻¹ Ca²⁺ concentrations respectively. Compared with the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca²⁺ concentrations and their contents were in the order: root>leaf>bark. Based on the results of this study, the experiment has been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil. Foundation item: This paper is supported by National Natural Science Foundation of China (No. 39970608). Biography: Fang Shengzun (1963), male, Professor in Stiiviculture, Nanjing Forestry University, Nanjing 210027, P.R. China. Responsible editor: Zhu Hong     

Multiple modelling of water chemistry flows assessed in a mountain spruce catchment

The study was carried out over a period of 1999–2003 in the Dupniański Stream catchment located in Silesian Beskid Mts. Region (Southern Poland). Analysis of the chemical composition of bulk precipitation, throughfall, stemflow, surface flow, soil water (horizontal + vertical and vertical penetration) and outflow water samples was performed. The complex data matrix with more than 3,000 observations of water reaction, major anions (F⁻, Cl⁻, NO₃ ⁻, SO₄ ²⁻) and cations (NH₄ ⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe²⁺, Mn²⁺ and Zn²⁺) were treated by regression modelling. The modelling approach took into account seasonal variability according to winter and growing season, as well as chronosequence of spruce stands. The retention of considerable levels of contaminants by the canopy, and their removal or washout from needles by rainfall caused changes in the concentration of anions and cations reaching the soil surface compared to the concentrations in bulk precipitation. In the youngest stand, most elements except NH₄ ⁺, SO₄ ²⁻ and K⁺ were retained in the canopy, and even H⁺ ions were neutralized. In the older stands, most elements increased in net throughfall fluxes, and the acidity increased strongly. Soil water was slightly correlated with throughfall, while outflow water showed no correlations with the above ground water flows, and seemed to depend mostly of the bedrock.     

广州市酸雨对不同森林冠层淋溶规律的研究

１９９８年４月至１９９９年３月对广州市白云山马尾松林和常绿阔叶林、广州市龙眼洞马尾松林两试验点进行了酸雨的监测,并测定和分析了林内穿透雨物理量及化学量,旨在探讨酸雨对不同森林冠层养分淋溶规律的影响。结果表明：（１）广州市酸雨占次数的７９．７％或占降雨量的９５．１％。（２）酸雨通过林冠层后,ｐＨ值明显增加。（３）在马尾松林和常绿阔叶林中,某些单次降雨出现ＳＯ４＾２－、ＮＯ３＾－、ＮＨ４＾＋Ａｌ＾３＋、Ｎａ＾＋的负淋溶现象,说明森林对这些离子（特别是ＮＯ３＾－、Ａａ＾３＋）具有吸收作用;阔叶林全年的ＮＯ３＾－和Ａｌ＾３＋净淋溶为负值,说明阔叶林比马尾松林对这两种离子具有更强的吸收能力。（４）雨水酸度增加（即ｐＨ值减小）,明显提高阳离子Ｃａ＾２＋、Ｍｇ＾２＋、Ｋ＾＋和Ｎａ＾＋冠层淋溶面分率。（５）ＮＨ４＾＋、ＳＯ４＾     

Response of five tree species to salinity and waterlogging: shoot and root biomass and relationships with leaf and root ion concentrations

Unproductive saline and waterlogged (WT) wastelands could be beneficially transformed into agroforestry systems using trees tolerant to these stresses. We studied the salinity and waterlogging tolerance of five Australian tree species (Acacia salicina, Casuarina glauca, Casuarina obesa, Eucalyptus camaldulensis and Eucalyptus occidentalis) during seedling stage and their relationships with root and leaf ion concentrations. 8-month old plants were exposed for 5 months to five irrigation water salinity treatments (EC values between 2 and 22 dS m^?1) and two waterlogging treatments (drained or WT). The salinity tolerance of the five species was high, although decreased in WT conditions. Irrespective of salinity, the two Casuarina species were more tolerant and the other three species were less tolerant to WT than drained conditions. In all species, salinity and waterlogging increased leaf Cl^? and Na⁺ and decreased leaf Ca²⁺, but not leaf K⁺. Root Cl^? and Na⁺ increased with salinity but not with waterlogging. Salinity tolerance was negatively correlated with Cl^? and Na⁺ leaf accumulation rates per unit increase in salinity. Waterlogging reduced the ability of the seedlings to exclude Cl^? and Na⁺ from the leaves. The two most salt tolerant Casuarina species under both drained and WT conditions showed the highest leaf Cl^? and Na⁺ exclusion and the highest root Cl^? and Na⁺ accumulation, suggesting that sequestration of these toxic ions in their roots was a significant salt-tolerant mechanism. Revegetation of saline and WT wastelands with these tolerant Casuarina species could be profitably used for biomass, biofuel and renewable energy production.     

Chemical content and seasonal variation of throughfall and litterflow under individual trees in the Hyrcanian forests of Iran

We assessed the effect of seasons and the tree species velvet maple (Acer velutinum Boiss), Hainbuche hornbeam (Carpinus betulus L.) and chestnut-leaved oak (Quercus castanefolia C. A. Mey.; Fagaceae) on nutrient fluxes (Na⁺, K⁺ and Ca²⁺) in throughfall (TF) and litter flow (LF) from January 2012 to February 2013. Potassium (K⁺) and calcium (Ca²⁺) in total TF and LF over the measurement period significantly differed between 3 the species (p < 0.05). Maple and oak trees had significantly higher fluxes of K⁺ and Ca²⁺ in their TF, respectively. The average quantity of nutrients in LF was significantly higher in the leafy season than in the leafless season for all cations except for Na⁺. Under velvet maple trees, the average flux of nutrients (Na⁺, K⁺, and Ca²⁺) in TF was significantly higher than LF. Lastly, leaching of potassium (K⁺) and calcium (Ca²⁺) in LF during the measurement period was significantly lower than TF under the hornbeam trees. Our results suggest that different tree species may impact the nutrient availability and possibly the sustainability of Hyrcanian forests. Further research is needed to determine how managing different species will affect the long-term nutrient status of these forests.     

Nutrient element contents of cutting seedlings of hybrid species （ Liriodendron chinense x tulipifera）

The cutting seedlings ofLiriodendron chinense xtulipifera were treated with the different concentrations of auxin (treatment₁: IBA of 50 g·kg⁻¹+NAA of 300 g·kg⁻¹; treatment₂; IBA of 100 g·kg⁻¹+NAA of 300 g·kg⁻¹). The biomass nutrient element contents for different organs (root, stem, leaf) of cutting seedling ofLiriodendron chinense xtulipifera were measured by the dry method, Kjeldahl method and Atomic Absorption Spectroscopy method. The result showed that the biomass of root, stem, and leaf of the cutting seedling treated with auxin was all remarkably increased. The contents of element C in root, stem and leaf had no significant difference between the control and auxin treatments, while the contents of N, P, K and Ca in stem were much lower than that in leaf and root. Variance analysis showed that for the same organ with different concentration treatment of auxin, the four nutrient elements (N, P, K, and Ca) had no significant difference in contents, while there existed significant or very significant difference in contents of the four nutrient elements in different organs with the same concentration auxin treatment. The N, P, K and Ca contents were very low in cutting seedlings; as a result, additional fertilizer should be applied to the seedlings when they were planted in the field. Foundation item: This paper was supported by Jiangsu Province Science Foundation (BE96350). Biography: ZHANG Xiao-ping, (1972-), female, Ph. Doctor in Nanjing Forestry University. Nanjing 210037, P. R. China. Responsible editor: Zhu Hong     

重庆酸雨区缙云山典型林分冠层酸雨淋洗特征

选取重庆缙云山的针阔混交林、常绿阔叶林、毛竹林、灌木林4种典型林分,观测酸性降水过程中林外雨、穿透雨及干流等林内水分转换分量中的主要离子含量变化,分析林分冠层对雨水化学组成的影响,结果表明:(1)降雨中的离子当量浓度大小依次是SO42-＞Ca2+＞ NH4+＞Mg2+＞K+＞Na+＞NO3-;(2)降雨经过林冠层后pH值降低,干流的酸化程度增加最大;(3)降雨经林冠层后离子浓度明显增加(除灌木林),穿透雨中通量增加最大的阴离子和阳离子分别为SO42-(2.19×103～6.47×103 eq·hm-2)和Ca2+(1.41×103～3.39×103 eq-hm-2),离子来源主要为大气沉降和植物分泌物或淋出;(4)同一离子在不同林分的干流和穿透雨中的通量变化不同,反映出不同林分冠层的离子交换性差异.在针阔混交林中,林下降雨净淋溶量大小顺序为SO42-＞Ca2+＞ NO3-＞K+＞NH4+＞Mg2+＞ Na+;常绿阔叶林为SO42-＞ Ca2+＞ K+＞NO3-＞ NH4+＞ Mg2+ ＞Na+;毛竹林为Ca2+＞ SO42-＞ K+＞NO3-＞ NH4+＞Na+＞Mg2+;灌木林为Ca2+＞ NO3-＞ K+＞ Na+＞Mg2+＞ NH4+＞ SO42-.     

盐胁迫对柳树无性系SH31离子含量及光合作用的影响

以柳树无性系SH31为试材,研究了NaCl溶液半抑制浓度胁迫下根、茎、叶中Na⁺、K⁺、Ca²⁺ 的分布规律及叶片光合特性的变化。结果表明:在NaCl溶液半抑制浓度(0.6%)下,SH31耐盐性较强;在0.6% NaCl溶液胁迫下,根部在前16 d积累大量Na⁺并拦截部分Na⁺向地上部运输;盐胁迫降低了根、茎部对 K⁺ 的吸收,而叶部却保持较高的K⁺ 含量来维持离子平衡;Ca²⁺含量在根、茎、叶中与对照的相当。在NaCl溶液半抑制浓度盐胁迫下,SH31 的净光合速率前7 d降低之后保持稳定,而气孔导度、蒸腾速率、胞间CO₂先降后升,表明前7 d的蒸腾速率下降的主要原因在于气孔限制。SH31根部对Na⁺ 选择性吸收并维持K⁺、Ca²⁺的高含量及维持较高光合作用是其重要的耐盐机制。     

Calcium mineral nutrition increases the tolerance of Quercus ilex to Phytophthora root disease affecting oak rangeland ecosystems in Spain

Root rot caused by the soil-borne pathogen Phytophthora cinnamomi is leading to significant oak tree mortality in rangeland ecosystems in south western Spain. Susceptibility to P. cinnamomi infections of Q. ilex seedlings with a standard nutrition, deficient in K⁺, and deficient in Ca²⁺, was tested. Oaks deficient in K⁺ showed high values in Ca²⁺ content and were tolerant to the disease. Nutritional deficiency in Ca²⁺, however, did not lead to a higher K⁺ level in plants and induced poorer root development. In addition, K⁺ plant content does not appear to have any effect on pathogen tolerance. Based on these results, we conclude that satisfactory calcium nutrition may confer Holm oaks with a greater tolerance to root disease caused by P. cinnamomi. For this reason, limestone supplements are recommended as a measure against root rot caused by P. cinnamomi in rangelands in southern Spain, as a good option for control of oak root disease.     

钙浓度对马尾松幼苗生长和生理特征的影响

[目的]在不同供Ca2+水平下对马尾松幼苗生长及生理特性进行研究,以确定适宜马尾松生长的钙浓度,为马尾松人工林培育及合理施用钙肥提供参考。[方法]以半年生马尾松幼苗为试材,采用温室内砂培,研究不同供Ca2+水平(0.0、0.4、1.0、2.0、3.0、4.0 mmol·L~(-1)(CK))对马尾松生长及生理指标的影响。[结果]不同供Ca2+水平处理5个月后,在Ca2+水平为1.0、2.0 mmol·L~(-1)时,马尾松幼苗的株高增量和地径增量较高,其中,2.0 mmol·L~(-1)Ca2+水平的株高增量和地径增量最高。马尾松幼苗对Ca2+水平适应能力强弱顺序为2.01.00.43.00.04.0 mmol·L~(-1)(CK)。在不同生长期内,随着供Ca2+水平的增加,马尾松针叶中ROS(O2-产生速率、H2O2浓度)、MDA含量、抗氧化酶(SOD、POD、CAT和APX)活性、抗氧化物质(GSH、As A)含量、脯氨酸含量均先降低后增加,最小值均在1.0 mmol·L~(-1)或2.0 mmol·L~(-1)处理中;类胡萝卜素含量先增加后降低,其最高值均在2.0 mmol·L~(-1)处理中。马尾松幼苗的株高增量和地径增量与类胡萝卜素含量关系不明显,而与其他生理指标均呈显著负相关。[结论]马尾松幼苗适宜在1.0 2.0 mmol·L~(-1)Ca2+水平的环境中生长。在马尾松林地中,应对土壤有效钙含量进行测定,并结合植株的生长和生理特征进行综合评价后,科学合理施肥以提高生产力。