外源硝态氮对菊芋耐海水胁迫的影响

A hydroponic experiment with six treatments, i.e., 0% seawater （control）, 10% seawater, 25% seawater, 0% seawater ＋ N （7.5 mmol L-1 NaNO3）, 10% seawater ＋ N （7.5 mmol L-1 NaO3）, and 25% seawater ＋ N （7.5 mmol L-1 NaNO3）, was carried out to study the effect of nitrogen addition on the growth and physiological and biochemical characteristics of Jerusalem artichoke （Helianthus tuberosus） seedlings under seawater stress. The 10% seawater stress treatment had the least effect on plant growth while at 25% seawater growth was significantly inhibited. The malondialdehyde content and electrolyte leakage in leaves under 10% seawater were similar to those of the control, but significantly higher under the 25% seawater stress. The activities of superoxide dismutase, peroxidase and catalase in the leaves increased concomitantly with increasing seawater concentration and time. Proline and soluble-sugars in the leaves and Na^＋, K^＋, and Cl- contents in shoots and roots increased significantly with the concentration of seawater increasing. Nitrogen addition resulted in increasing fresh and dry weights of shoots and roots compared with seawater treatment without N. Nitrogen supplementation also significantly enhanced the activities of antioxidant enzymes in leaves. Addition of N to seawater enhanced the contents of proline and soluble-sugars in the leaves and K^＋ and total-N in the aerial parts and roots of H. tuberosus, but it resulted in declined concentrations of Na^＋ and Cl- in the aerial parts and roots. Nitrogen addition ameliorated the toxicity of seawater by improving the antioxidative enzymes, accumulating of proiine and soluble-sugars, and altering the distribution of inorganic ions in H. tuberosus.     

海水处理下长春花体内生物碱含量增加

A sand culture experiment was conducted to determine the effects of different seawater (5% and 10%) treatments on plant growth, inorganic ions, indole alkaloid concentrations and yields of Catharanthus roseus, in an effort to increase the alkaloid yield by artificial cultivation. The total fresh and dry weights and tissue K⁺ concentrations decreased, but Na⁺ concentrations increased in the plant roots, stems and leaves of C. roseus under seawater stress as compared to the control. The concentrations and yields of vindoline, catharanthine, vinblastine and vincristine increased under seawater stress. The concentrations and yields of these alkaloids were higher in 5% seawater-treated plants than those in the 10% seawater-treated plants. Considering the industrial production, 5% seawater treatments could reduce the cost of producing alkaloid. In the control plants, the highest alkaloid concentrations reached a peak at 100 days after planting, suggesting that plant harvest must be optimized in terms of growth duration.     

低氮胁迫下拟南芥低氮耐性突变体lnt1的氮代谢特征

A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen (N) metabolism of a low-N tolerant mutant (lnt1) of Arabidopsis thaliana under different N levels as compared with the wildtype (WT) Arabidopsis. On the agar medium, no apparent growth differences were observed between the lnt1 and WT plants under a normal N level of 9 mmol L^-1 NO₃^-. However, under a low N level of 0. 18 mmol L^-1 NO₃^-, the growth of the WT plants was greatly retarded, while the lnt1 plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lnt1 mutant had higher activities of glutamine synthetase (GS) and NADH-dependent glutamate synthase (NADH-GOGAT) in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium (NH₄⁺) but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.     

两种菊芋耐盐差异研究

To explore genetic variability for two Jerusalem artichoke (Helianthus tuberosus) cultivars, N1 (the sixth-generation cultivated with 75% seawater irrigation for six years) and N7 (a general variety), a experiment was conducted to study the changes in physiological attributes under different concentrations (0%, 10% and 25% of seawater concentration in greenhouse and 0%, 30% and 50% of seawater concentration in the field) of seawater salinity stress. In the greenhouse experiment, decreases of dry growth rate, but increases of dry matter percentage and membrane injury occurred in both the genotypes at 10% and 25% seawater treatments, although lesser cell membrane damage was observed in N1 than N7. N1 accumulated greater contents of Na⁺, Cl^-, soluble sugar and proline in leaves compared with N7. In the field experiment, the yields of shoot, root and tuber, and the contents of total-sugar and inulin in tubers of N1 were higher than those of N7. Lesser degree of salt injury in N1 indicated that the relatively salt-tolerant cultivar had higher K⁺/Na⁺ ratio, lower Na⁺/Ca²⁺ ratio, and the salt-induced enhancement of osmotic adjustment.     

缺锌和高锌胁迫下苹果根系有机酸对锌的内稳性的响应

To elucidate the mechanisms of tolerance to zinc (Zn) deficiency and Zn toxicity in the root of apple trees, the apple rootstock Malus hupehensis (Pamp.) Rehd seedlings were selected to study the responses of organic acids to Zn homeostasis in roots under low Zn (0 μmol L-1 ), adequate Zn (as control, 4 μmol L-1 ) and toxic Zn (100 μmol L-1 ) treatments. The differences of Zn concentrations and accumulations in the roots were highest, compared with those in the stems and leaves, when apple seedlings were subjected to low and toxic Zn treatments for 1 d. The concentrations and accumulations of oxalic and malic acids in the roots in the low and toxic Zn treatments increased by 20% to 60% compared with those of the control treatment. Significantly negative correlations were found between the total Zn concentrations and the concentrations of oxalic and malic acids in the roots under 1 d of low Zn treatment. However, contrary correlations were found for the toxic Zn treatment. Meanwhile, the maximum influx rates of Zn 2+ under low and toxic Zn treatments increased by 30% and 20%, respectively, compared with the rate of the control treatment. Both Zn deficiency and Zn toxicity increased the concentrations of organic acids in root after short-time Zn treatment, which could resist Zn stress through balanding Zn homeostasis in M. hupehensis Rehd.     

南亚热带三种不同土地利用历史的森林生态系统土壤可交换阳离子对模拟氮沉降的响应

The effects of simulated nitrogen (N)deposition on soil exchangeable cations were studied in three forest types of subtropical China. Four N treatments with three replications were designed for the monsoon evergreen broadleaf forest (mature forest):control (0 kg N ha^-1 year^-1), low N (50 kg N ha^-1 year^-1), medium N (100 kg N ha^-1 year^-1)and high N (150 kg N ha^-1 year^-1), and only three treatments (i.e., control, low N, medium N)were established for the pine and mixed forests. Nitrogen had been applied continuously for 26 months before the measurement. The mature forest responded more rapidly and intensively to N additions than the pine and mixed forests, and exhibited some significant negative symptoms, e.g., soil acidification, Al mobilization and leaching of base cations from soil. The pine and mixed forests responded slowly to N additions and exhibited no significant response of soil cations. Response of soil exchangeable cations to N deposition varied in the forests of subtropical China, depending on soil N status and land-use history.     

稀释海水灌溉的芦荟中矿质营养与有效成分分布情况研究

With increasing demand for irrigation water, agricultural scientists and planners pay more attention to the utilization of diluted seawater as an alternative source for irrigation of crops. A greenhouse pot experiment was conducted to study how seawater stress（SS） affects growth, water content, cationic accumulation, and active ingredients in leaves of Aloe vera after 30 d of growth in nutrient media with 0%（control）, 22%（22% SS）, and 42%（42% SS） seawater stress. Results indicated the SS did not change dry biomass of leaves and stems, but gradually decreased biomass allocation to roots with increasing seawater stress. Na^＋ and Cl^- in A. vera plant did not increase obviously with a big increase in seawater percentage due to low transpiration of Aloe vera. 42% SS decreased N concentration in most plant organs, but did not change or increased P concentration. Seawater stress tended to decrease concentrations of K^＋ and Ca^2＋ in A. vera. However, seawater salinity tended to increase the concentrations of aloin concentration in top（young） and middle leaves, and there was no significant effect of both stresses on aloin concentration in base（old） leaves. The 42% SS treatment decreased polysaccharide concentrations only in the base leaves, but not in top and middle leaves. In summary, supplying suitably diluted seawater for 30 d could increase the qualities and value of A. vera, without substantial effects on shoot dry biomass production.     

中国南方红壤上作物产量和土壤性质对长期施肥的响应

A 15-year fertilization experiment with different applications of inorganic N, P and K fertilizers and farmyard manure (M)was conducted to study the yield and soil responses to long-term fertilization at Qiyang, Hunan Province, China. Average grain yields of wheat and corn (1 672 and 5 111 kg ha^-1, respectively)for the treatment NPKM were significantly higher than those (405 and 310 kg ha^-1)of the unfertilized control and single inorganic fertilizer treatments. Compared with the corresponding initial values of the experiment, all treatments showed a yield decline of 9 to 111 kg ha^-1 year^-1 in wheat and 35 to 260 kg ha^-1 year^-1 in corn, respectively, and a significant pH decline of 0.07 to 0.12 pH year^-1, except for the treatments PK and NPKM. After long-term fertilization, the soil organic C, soil available P, exchangeable Ca²⁺ and Mg²⁺ and available Cu²⁺ and Zn²⁺ contents were higher in the treatment NPKM than in the treatments applied with inorganic fertilizer only. Compared to the treatment NPK, the treatment NPKM, where manure partially replaced inorganic N, had a positive impact on arresting the decline of soil pH. This improved grain yields of wheat and corn, suggesting that application of NPK fertilizer in combination with farmyard manure is important to maintain soil fertility and buffering capacity in red soil.     

黄土高原半干旱区不同土地利用下的土壤有机碳、碳组分和土壤营养

Cropland (CP), native grassland (NG) and two shrub land treatments which were converted from cropland in 1985:seabuckthorn (Hippophae rhamnoides L. ) (ST), and branchytamarisk (Tamarix ramosissima) (BT) were investigated to evaluate effects of land use conversion on soil organic carbon (SOC) and soil nutrients in the semi-arid region of the Loess Plateau of China. Total organic carbon (TOC), light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), total N (TN), nitrate nitrogen (NO₃^--N) and nitrite nitrogen (NO₂^--N), ammonium nitrogen (NH₄⁺-N), total P, and available P (AP) were measured. The results showed that SOC in NG, ST and BT were 12.7%, 27.7% and 34.8% higher than that of the cropland, respectively. LFOC, light fraction (LF) dry matter, ratio of TOC to TN (C/N) and the ratio of TOC to AP (C/P) were higher in the shrub land or native grassland than in the cropland. Cropland had the highest TN, the sum of NO₃^--N and NO₂^--N, TP and AP due to the use of chemical fertilizers. TOC significantly correlated with LFOC, HFOC and C/N. LFOC significantly correlated with dry matter of the LF and C/N. TN, the sum of NO₃^--N and NO₂^--N and AP were significantly negatively correlated with TOC and LFOC. Therefore, land use conversion from cropland to shrub land, or maybe grassland, contributed to SOC sequestration and improved soil nutrients stabilization.     

印度西高止和西海岸地区Arthrosphaera及相关土壤动物的分布

Seven sampling sites in each of three biomes (Western Ghats, foothills of Western Ghats and west coast) of southwestern India were investigated to study the distribution, abundance and ecology of pill millipedes (Arthrosphaera) and associated fauna in relation to edaphic features. Abundance and biomass of Arthrosphaera and other millipedes were the highest in Western Ghats, while earthworms were in foothills. Arthrosphaera magna and Arthrosphaera spp. were common in Western Ghats and foothills respectively, while no Arthrosphaera were found in the west coast. None of the sampling sites consisted of more than one species of Arthrosphaera. Biomass of Arthrosphaera, other millipedes and earthworms significantly differed in Western Ghats (P = 9.48 × 10^-7) and foothills (P = 1.35 × 10^-8), as did the biomass of species of Arthrosphaera (P = 2.76 × 10^-7) between Western Ghats and foothills. Correlation analysis revealed that biomass of Arthrosphaera was significantly (P = 0.01, r = 0.45) correlated with soil organic carbon rather than other edaphic features (pH, phosphate, calcium and magnesium). Distribution pattern, abundance, biomass and ecology of Arthrosphaera of Western Ghats in relation to soil qualities were compared with millipedes of other regions of the world.     

基于光谱稳定目标的经验线性大气校正方法研究

By using speetrally stable targets, the empirical line （EL） method was tested to correct the multispectral IKONOS imagery acquired over Putuo Mountain, Zhejiang, China. A series of calibration targets, which were spectrally stable over time, were selected to establish the linear predicted equation. Subsequently, a series of spectrally stable validation targets were selected to assess the accuracy of the equations. And, validation targets, which were speetrally unstable over time, were used to test the feasibility of using the EL method to calibrate the archival remotely sensed data. Ground reflectance measurements for each target were made using an ASD FieldSpec spectroradiometer. A Trimble GeoXTTM GPS unit with sub-meter accuracy was used to estimate the target position accurately. Linear regression equations for four tKONOS bands were derived. The coefficients of determination for the blue, green, and red bands were all greater than 0.9800 and it was 0.9697 for the near infrared band. It was concluded that reasonable results could be obtained by using speetrally stable targets.     

不同品种菊芋对海水处理响应的生理指标筛选

试验采用温室水培试验的方法，系统评价了7个典型品种菊芋对0.15％，30％海水的响应，并对不同品种菊芋对海水处理响应的生理指标进行了筛选。结果表明：在15％和30％海水处理下地上部和根鲜重、干重、含水率较对照降低，30％海水处理下更显著，而地上部和根Na^＋和Cl^-含量随海水浓度增加显著增加，在15％和30％海水处理下菊芋幼苗地上部和根K^＋含量均高于对照处理。菊芋幼苗地上部和根鲜重和干重与根部Na^＋含量呈极显著负相关，地上部和根鲜重与地上部和根部Cr含量呈显著负相关，地上部和根干重与地上部和根部K^＋含量呈显著正相关。根据菊芋在海水处理下的表现分为3种类型：高度耐海水型、中度耐海水型和低度耐海水型。在评价不同基因型菊芋对海水的响应时，地上部和根鲜重、干重及含水率的下降幅度和Na^＋、K^＋和Cl^-含量可作为主要的生理指标。     

半干旱地区海涂海水灌溉对不同品系菊芋产量构成及离子分布的影响

在半干旱海涂以不同品系菊芋（Helianthus tuberosusL．）为材料进行田间试验，研究了海水灌溉对不同品系菊芋产量构成及离子分布的影响。结果表明：（1）南芋2号根和地上部生物量较其他品系大，南芋5号和南芋3号株高在各浓度海水灌溉下均显著高于其他菊芋品系，而茎粗在各处理下变化不一致，在30％海水灌溉下，南芋1号根和地上部物质积累未受到抑制作用，其他各品系菊芋的根和地上部物质积累受到了一定抑制。（2）各菊芋品系块茎产量差异较显著，在30％海水灌溉下，南芋2号产量显著高于其他品系，各菊芋品系块茎单重在各处理下差异也较显著，南芋1号和2号块茎单重最大，各菊芋品系块茎总糖和菊糖含量差异较显著。（3）随海水浓度的增加，各品系菊芋根、茎和叶的C1-和Na^＋含量均增加，但品系间差异较显著，叶片的Na’含量显著低于根和茎的Na’含量。从生物积累量和块茎产量、总糖和菊糖含量及离子分布看，南芋1号和南芋2号较其他品系更适合在半干旱海涂利用适当浓度海水进行灌溉种植。     

莱州湾海涂海水灌溉菊芋的磷肥效应的研究

在连续3年莱州湾海涂海水灌溉试验的基础上,2003年就不同浓度海水灌溉菊芋的磷肥效应进行了田间试验研究。结果表明,在海水灌溉下,磷肥对菊芋的增加产量与增产幅度均高于淡水灌溉,在50%海水浓度范围内,随着灌溉海水浓度增加磷肥的增产效应也逐渐提高,以50%浓度海水灌溉磷肥增产效应最大;海水灌溉下,施磷肥能显著促进菊芋对K+、Ca2+和Mg2+等有益离子的吸收与运输,尤其是明显提高菊芋在海水灌溉下的SK,Na,而抑制菊芋对Na+及Cl-等有害离子的吸收;在75%的海水浓度范围内,灌溉的海水浓度越高,磷肥对上述离子的影响强度越大;海水灌溉下,施用磷肥明显促进菊芋根部氮的含量,P3(P2O560kg/hm2)与P1(P2O50kg/hm2)处理相比较,在淡水、25%海水、50%海水、75%海水灌溉处理下,菊芋根部含氮量增加0.43、0.64、0.64、0.51个百分点。     

钙对NaCl胁迫下马铃薯脱毒苗离子吸收、分布的影响

【目的】马铃薯是对盐分较敏感的农作物,土壤盐渍化会严重影响马铃薯的生长发育及其产量和品质。有关钙对Na Cl胁迫下马铃薯离子吸收、分布的研究较少。本文通过研究不同浓度Ca Cl2对Na Cl胁迫下马铃薯脱毒苗离子吸收、分布和运输的影响,探讨钙对Na Cl胁迫下马铃薯的调控机制,为盐渍土上马铃薯的生产提供理论依据与技术支持。【方法】以‘克新一号’马铃薯品种为试验材料,采用组织培养方法,将0、5、10、15和20 mmol/L Ca Cl2与0、25、50和75 mmol/L Na Cl分别添加到MS+2mg/L B9+3%蔗糖+0.9%琼脂培养基中,制成不同处理组合的培养基。将继代培养的脱毒苗按单节茎段剪切接种到培养基中进行培养。接种30天时调查脱毒苗生物量和Na+、Cl-、K+、Ca2+、Mg2+、P积累量,并分析Na+/K+、Na+/Ca2+、Na+/Mg2+比值及根系与茎叶的SK、Na、SMg、Na和SCa、Na值,探讨离子吸收、运输及分布情况。【结果】Na Cl胁迫抑制马铃薯脱毒苗的生长,随Na Cl胁迫浓度的增加,马铃薯脱毒苗鲜重、干重显著下降,各器官Na+和Cl-含量极显著增加,K+含量显著下降,Ca2+和Mg2+含量减少,茎、叶中P含量降低而根中P含量增加。Na+/K+、Na+/Ca2+、Na+/Mg2+比值随Na Cl胁迫浓度的增加而升高。随Na Cl胁迫浓度的增加,马铃薯脱毒苗根系与茎叶的SK、Na和SMg、Na值逐渐降低,SCa、Na值呈先升高后降低趋势。0、25和50 mmol/L Na Cl胁迫浓度下,以10 mmol/L Ca Cl2处理的马铃薯脱毒苗根、茎叶鲜重和干重最高,75 mmol/L Na Cl胁迫下以15 mmol/L Ca Cl2处理的马铃薯脱毒苗生物量最高。各Na Cl胁迫浓度下,添加Ca Cl2后,马铃薯脱毒苗各器官Na+含量明显降低,Cl-含量显著增加,K+、Ca2+、Mg2+含量升高,P含量先降低后升高。0、25、50和75 mmol/L Na Cl胁迫浓度下,添加适量Ca Cl2可明显降低马铃薯脱毒苗各器官Na+/K+、Na+/Ca2+、Na+/Mg2+比值,提高SK、Na、SMg、Na和SCa、Na值,增强K+、Ca2+、Mg2+向地上部的选择运输能力,抑制Na+向地上部的选择运输能力,维持细胞内离子平衡,缓解盐胁迫造成的营养亏缺。【结论】Na Cl胁迫下添加外源钙,能够有效改善马铃薯脱毒苗体内的离子平衡,促进营养吸收,Na+向叶片选择运输能力降低,K+、Ca2+、Mg2+向地上部的选择运输能力增强,离子在各器官水平上的区域化分布发生改变是钙缓解盐胁迫的重要生理机制之一。     

干旱胁迫下钾素对甘薯碳水化合物及内源激素含量的影响

【目的】研究干旱胁迫下施钾量对不同生长时期甘薯碳水化合物及内源激素含量的影响,为甘薯的抗旱高产栽培提供理论依据。【方法】选用食用型甘薯品种‘泰中6号’为材料,以硫酸钾（K₂SO₄）为供试肥料,水分处理设土壤最大持水量的60%～70%和30%～40%,依次代表正常供水（W1）和干旱胁迫（W0）;钾肥设K0、K1、K2、K3四个水平,K₂O用量分别为0、120、240和360 kg/hm2。分析了不同生长时期甘薯干物质含量、淀粉和可溶性糖含量、内源激素含量及收获期块根产量。【结果】干旱胁迫下甘薯植株干物质含量、块根和淀粉产量显著降低,施钾有利于甘薯植株干物质含量的提高、块根的膨大和淀粉的生成和积累,甘薯植株和块根干物质含量、块根淀粉含量和积累量最大均为K2处理,较K0提高幅度最大分别达到31.7%、43.6%、10.6%和50.6%。相同钾用量条件下,干旱胁迫下块根单薯重显著高于正常灌水,单株结薯数显著低于正常灌水。正常灌水条件下施钾后甘薯叶片可溶性糖含量降低,而块根可溶性糖含量升高,干旱胁迫下施钾使甘薯叶片和块根可溶性糖含量增大,较K0提高幅度最高分别达到31.4%和36.0%。干旱胁迫下施钾后甘薯叶片和块根IAA、ABA、ZR和GA含量显著增大,较K0提高幅度最高分别达到12.7%、15.7%、12.0%、10.4%和21.4%、15.6%、65.7%、13.0%,促进了甘薯植株碳水化合物含量和干重的提高,块根淀粉积累速率增大。【结论】干旱胁迫下施钾促进了干物质向块根的分配,提高了甘薯块根单薯重,从而增加了单位面积甘薯块根产量。干旱胁迫下钾素提高甘薯块根和叶片内源激素（ABA、IAA、ZR、GA）含量,块根内源激素含量的增加促进了块根淀粉的合成和积累,叶片内源激素含量的增加促进了地上部茎叶生长、茎叶干物质积累和叶片可溶性糖含量的增加,增强了甘薯的抗旱性。     

Alkaloid Accumulation in Catharanthus roseus Increases with Addition of Seawater Salts to the Nutrient Solution

A sand culture experiment was conducted to determine the effects of different seawater (5% and 10%) treatments on plant growth,inorganic ions,indole alkaloid concentrations and yields of Catharanthus roseus,in an effort to increase the alkaloid yield by artificial cultivation.The total fresh and dry weights and tissue K + concentrations decreased,but Na + concentrations increased in the plant roots,stems and leaves of C.roseus under seawater stress as compared to the control.The concentrations and yields of...     

不同浓度硒处理对彩叶草铅胁迫的EDXS和XRD分析

以彩叶草(Coleus blumei Benth.)为材料,用营养液培养方法,研究了不同浓度硒(Se)处理对浓度为1.0 mmol·L-1 Pb2+胁迫下彩叶草根、叶的形貌变化及其组分形态等变化,从光谱学角度初步探讨了硒对重金属铅毒害的缓解机制。结果表明:铅胁迫下的彩叶草根系C、K、Ca含量减少,O、Mg、Al、Si、Fe、Pb含量增加,叶片中的C、Mg、Al、Si、K、Ca、Fe含量减少,O、Cl含量增加。铅胁迫下硒处理的彩叶草根元素种类及其元素含量均发生了明显变化;根中晶体情况及其晶相也发生了相应变化。