Studies on shoot regeneration of lupins (Lupinus spp.)

Tests have been made to regenerate plants from different lupin species using leaf, leaf petiole and hypocotyl tissue of L. polyphyllus, L. hartwegii, L. angustifolius and L. luteus. Callus induction rates have been high with all plant parts from all tested lupin species. Regeneration success has been rather limited. One plant could be regenerated from hypocotyl material of L. polyphyllus. Only shoots appeared when using leaf explants from L. luteus or L. hartwegii as well as from leaf petiole tissue of L. hartwegii. With L. angustifolius one regeneration of unknown character occurred.     

European yellow lupine, Lupinus luteus, and narrow-leaf lupine, Lupinus angustifolius, as hosts for the pea aphid, Acyrthosiphon pisum

The pea aphid, Acyrthosiphon pisum Harris (Homoptera: Aphididae), fed, developed, and reproduced on yellow lupine, Lupinus luteus L. (Fabaceae: Genisteae). No clear preferences for any variety within L. luteus were found. Acyrthosiphon pisum showed negative values of relative growth rate and no aphid completed development on any variety of narrow-leaf lupine Lupinus angustifolius L. Aphids did not ingest phloem sap while probing on L. angustifolius and the probes were very short. All varieties of L. angustifolius were rejected by aphids during an early stage of probing in peripheral tissues, that is, epidermis or mesophyll. There were qualitative and quantitative differences in alkaloid and soluble sugar content between the two lupine species. Within species, the relative content of individual compounds differed among the varieties. Lupinus angustifolius contained four quinolizidine alkaloids (13-hydroxylupanine, dehydrolupanine, lupanine, and angustifoline), while L. luteus contained two (lupanine and sparteine). Lupanine occurred in all varieties of both lupine species. The total content of soluble carbohydrates was similar in L. luteus and L. angustifolius . The following cyclitols were found in both lupine species: myo -inositol, D-ononitol, and D-pinitol. Lupinus angustifolius also contained D- chiro -inositol. The study of aphid probing behaviour, development, and reproduction demonstrated that L. luteus is a suitable host plant for A. pisum while L. angustifolius is not. It is likely that the rejection of L. angustifolius by A. pisum was caused by chemical factors detected by aphids at the epidermis and mesophyll level.     

Effects of salinity on ultrastructure and ion distributions in roots of Plantago coronopus

Root cell structure and ion distributions have been examined in Plantago coronopus L. grown in the absence or presence of 110–125 m M NaCl. In both salt-treated and control plants, the inner cortical cells often had membrane whorls projecting into the vacuoles. These structures appeared to be continuous with the endoplasmic reticulum. In roots grown in saline conditions, the parenchyma cells surrounding the xylem vessels showed very uneven wall thickenings and corrugations.
In control roots, X-ray microanalysis of frozen hydrated bulk specimens showed that there were three levels at which discrete reciprocal changes in Na/K levels occurred: the outer-middle cortex, the endodermis and the xylem vessels. The first two of these were associated with high Mg, and the last with high Ca percentages. In the salt-treated roots, the overall Cl percentages were much lower than in the culture medium, being severely limited at the epidermis. Na and, to a lesser extent, Cl percentages decreased radially inwards, while those of K increased. The Na:Cl ratio decreased radially inwards across the cortex. The analytical validity of the data is discussed in relation to differential elemental losses during analysis, specimen topography and analytical spatial resolution. The results are interpreted in terms of the proposed involvement of Mg²⁺- and Ca²⁺-ATPases in ion uptake and regulation of translocation in Plantago coronopus roots.     

盐胁迫对空心莲子草生长和光合作用的影响

用NaCl浓度为0(对照)、50、100、150、200、250、300、350mmol/L处理空心莲子草[Alternantheraphiloxeroides(Mart.)Griseb]。结果表明:盐胁迫下,植株鲜重、干重和根冠比都下降,含水量和肉质化程度先略高于对照,而后逐渐下降;根、茎和叶中Na 含量呈上升趋势,而K 含量呈下降趋势,且在同一浓度的盐处理下,叶的Na 和K 含量最高,茎的次之,根的最低;游离氨基酸(free amino acid,FAA)逐渐减少,脯氨酸(proline,Pro)含量先略低于对照,而后则急剧上升,可溶性糖含量(soluble sugar,SS)的变化正相反;净光合速率(net photosynthetic rate,Pn)、气孔导度(stomatal conductance,Gs)和蒸腾速率(transpirationrate,Tr)呈下降趋势,胞间CO2浓度(intercellular CO2concentration,Ci)呈上升趋势;膜稳定性呈下降趋势。因此,空心莲子草是一种盐生植物,且最适盐浓度较低;Na 主要积累在地上部的茎和叶中。推测它有可能向盐渍土壤蔓延。     

Influence of silicon on microdistribution of mineral ions in roots of salt-stressed barley as associated with salt tolerance in plants

Two contrasting barley (Hordeum vulgare L.) cultivars: Kepin No.7 (salt sensitive), and Jian 4 (salt tolerant) were grown hydroponically to investigate the microdistribution of mineral ions in roots as affected by silicon (Si) with respect to salt tolerance. The experiment was undertaken consisting of two treatments with 3 replicates: (i) 120 mmol · L-1 NaCl alone (referred to as Si-NaCl+), (ii) 120 mmol·L-1 NaCl + 1.0 mmol · L-1 Si (as potassium silicate) (referred to as Si+NaCl+). Plant root tips were harvested for microanalysis using an energy dispersive X-ray microanalyzer (EDX) 30 d after transplanting. Higher Cl and Na X-ray peaks were recorded in the root epidermal, cortical and stelar cells of roots for the treatment Si-NaCl+ with the majorities of Na and Cl being accumulated in epidermal and cortical cells, while relatively low K peaks were observed regardless of the barley cultivars used. By contrast, considerably higher K peaks were detected in the epidermal, cortical and stelar cells of th     

X-ray microanalysis of ion distribution within root cortical cells of the halophyte Suaeda maritima (L.) Dum.

The ion content of compartments within cortical cells of mature roots of the halophyte Suaeda maritima grown at 200 mol·m^-3 NaCl has been studied by X-ray microanalysis of freeze-substituted thin sections. Sodium and Cl were found in the vacuoles at about four-times the concentration in the cytoplasm or cell walls, whereas K was more concentrated in the cell walls and cytoplasm than in vacuoles. The vacuolar Na concentration was 12- to 13-times higher than that of K. The Na concentration of cell walls of cortical cells was about 95 mol·m^-3 of analysed volume. The cytoplasmic K concentration within the mature cortical cells was estimated to be 55 mol·m^-3 of analysed volume.     

硅改善盐胁迫下库拉索芦荟生长和离子吸收与分布

Si2．0mmol／L处理明显缓解NaCl 100、200mmol／L胁迫120d对库拉索芦荟（Aloevera）生长的抑制作用。Si可显著降低NaCl胁迫下芦荟植株中的Na^＋和Cl^-含量,提高K^＋含量,从而显著降低K^＋／Na^＋,促进根对K^＋的选择性吸收（ASK,Na）和K^＋向地上部的选择性运输（TSK,Na）,以维持植株体内的离子稳态。根系和叶片横切面的X-射线能谱微区分析结果进一步证实了这一结果。Si改善盐胁迫下芦荟对K^＋的选择性吸收和运输的机制之一是通过显著提高盐胁迫下芦荟根细胞质膜H^＋ATPase、液泡膜H^＋-ATPase和液泡膜H^＋-PPase的活性。     

X-Ray Micro-Analysis of Cells and Cell Compartments of Atripiex spongiosa: II. ROOTS

Atripiex spongiosa was grown in hydroponic culture with additionof 0, 50, 200, 400 and 600 mM NaCl. Frozen, hydrated cells ofthe roots were analysed by X-ray micro-analysis. Comparisonswere made of meristematic cells at the root apex and vacuolatedcells 5.0 mm from the apex. High selectivitiy for K relativeto Na was found for the cytoplasm of meristematic cells andthere was little effect of increasing salinity on the ratiosNa/K, Cl/K, Na/P and CI/P. In the cell vacuoles of the cortex,selective uptake of K relative to Na also occurred, but to alesser extent than in the meristematic cells. Gradients werefound of decreasing ratio of Na/K from the epidermis to thestele. Measurements of chemical content of the roots and shoots ofthese plants showed that the ratio of Na/K was higher in theshoot than in the cortical cell vacuoles and higher again thanin the stele or meristematic cytoplasm. It is suggested thattransport of ions to the shoot of Atripiex spongiosa involvesselective exclusion of Na from the xylem parenchyma into thexylem, and that this may be general to other halophytes. Key words: Micro-analysis, X-ray, Cells, Atripiex spongiosa     

Physiological responses of the mangrove Rhizophora mangle grown in the absence and presence of NaCl

Abstract. Propagules of the mangrove, Rhizophora mangle L., were precultivated for 9 months in a greenhouse. The young plants were transferred into unaerated nutrient solutions without and with 200 mol m ³ NaCl and subsequently their growth, their water relations and the photosynthetic properties of their leaves were studied. Growth of the salttreated plants was significantly increased, while the control plants gradually died off after finishing the experiments. The shoot water potential and the stomatal resistance of the leaves were lowered while the chlorophyll contents and the chlorophyll a/b ratio in the leaves of salt-treated plants were increased by NaCl, the net result being an enhanced rate of CO₂ assimilation. The leaves of both sets of plants showed diurnal fluctuations in malic acid concentration which were more pronounced in the leaves of salt treated plants which, additionally, were more succulent. However, the plants showed no net CO₂ fixation at night, indicating that Rhizophora mangle is a CAM-cycling plant. After 200 d of cultivation without or with NaCl, the Na⁺, Cl and K⁺ concentrations in tissues and vacuoles were measured. Energy-dispersive X-ray microprobe analyses on root vacuoles of control plants reveal Na⁺ preference, on those of salt treated plants a strong K⁺ preference. Vacuolar K⁺ concentrations are neither affected by NaCl nor do they vary across the root radius. High vacuolar Na⁺ and Cl concentrations are found in the hypodermis followed by a stepwise decrease towards the inner root cortex cells. Ion concentrations of the photosynthetically active leaf tissues seem to be regulated by (1) radial filtration across the root cortex: (2) ion exchange of the xlem parenchyma cells: and (3) sequestration of Na⁺ and Cl in the hypodermal water storage tissue of the leaves.     

X-Ray Micro-Analysis of Cells and Cell Compartments of A triplex spongiosa: I. LEAVES

Atriplex spongiosa was grown in hydroponic culture with additionsof 0, 200, 400 and 600 mM NaCl. Frozen, hydrated cells and cellcompartments of young and mature leaf tissue were analysed byX-ray micro-analysis. Evidence for low K + Na and Cl content,and high K selectivity in the bundle sheath cytoplasm was obtainedfrom data on X-ray count ratios and on total X-ray counts. Vacuolesof the major cell types of the mature leaf had either high Kor high Na and Cl contents when grown in the absence or presenceof NaCl. Comparison of K, Na and Cl content of different cell types inthe mature leaf showed gradients in selectivity for K. relativeto Na between the bundle sheath cells and the bladder cells.In the young expanding leaves salt was sequestered in the numeroussalt bladders on the leaf surface, while the cytoplasm and developingvacuoles of undifferentiated cells contained largely K and littleNa or Cl. The results support general views on the compartmentation ofsalt in plants cells in relation to osmotic or saline stress. Key words: Atriplex spongiosa, X-ray analysis, Salinity, Compartmentation, Leaf     

Intercellular Compartmentation of Ions in Barley Leaves in Relation to Potassium Nutrition and Salinity

X-ray microanalysis was used to determine the distributionsof several nutrient elements between vacuoles of epidermal andmesophyll cells in barley leaves and these distributions wererelated to shoot nutrient concentrations. Under the growth conditionsused, P was found only in mesophyll vacuoles, never in the epidermis.In contrast, Cl and Ca were located almost exclusively in theepidermis while K and Na were more evenly distributed betweenthe two cell types. The compartmentation of Ca and Cl in theepidermis was maintained over a wide range of tissue concentrationsof these ions. In particular, Cl was excluded from the mesophyllof salt-grown barley until the tissue concentration reachedabout 170 mol m^–3 and then it appeared in the vacuolesof these cells, but only at low concentrations. In contrast,Na was not excluded from the mesophyll of salt-grown or K-deficientbarley and there was evidence that this ion was preferentiallyaccumulated in the mesophyll. Nutrients were evenly distributedbetween the adaxial and abaxial epidermal layers, except K.which was at slightly higher concentrations in the adaxial epidermis.There was considerable variation in the concentrations of ionsin adjacent epidermal cells. The results indicate that intercellularcompartmentation of nutrients occurs in barley leaves and therole of this phenomenon in responses to nutrient deficienciesand salinity is discussed Key words: Compartmentation, barley, salinity, ions, potassium nutrition     

Cross compatibility between European and American Lupinus species

The results of attempted hybridization between European species of large-grained species of Lupinus, L. albus, L. angustifolius and L. luteus and between these and the South American species L. mutabilis are described. Pollen-tube growth in interspecific combinations differed significantly from those after self-pollination only when L. luteus , was the female parent. All combinations Involving L. mutabilis pollen exhibited unilateral compatible pollen-tube growth. Substantial evidence of ovule stimulation and enhanced pod retention was recorded in crosses between the European species and L. mutabilis , but viable seeds were not obtained. The indications, from pollen-tube growth and pod retention in certain crosses, are that genetical isolation between some of the species could be overcome.     

NaCl胁迫下野生和栽培大豆幼苗体内离子的再转运

采用NaCl根际处理和叶面饲喂^22Na方法,研究了野生大豆(Glycine soja)——耐盐的BB52、盐敏感的N23232和栽培大豆(Glycine max)——较耐盐的Lee68幼苗在盐胁迫及解除过程中对Na^ 、Cl^-的吸收和再转运。结果表明,在NaCl根际处理12h过程中,BB52和Lee68幼苗根对Na^ 、Cl^-吸收和向茎、叶的运输逐渐增加,10h时趋于稳定,Na^ 、Cl^-含量高低顺序是根＞茎＞叶。但N23232的Na^ 、Cl^-含量则是茎＞根＞叶。在用NaCl对根处理10h后再解除NaCl处理的0～36h内,BB52吸收的Na^ 、Cl^-较多地留于根部或转运至根茎过渡区,叶中较少。N23232吸收的Na^ 较多地转运至茎部,而Cl^-含量在幼苗各部分无差异。叶片饲喂^22Na 10h后,BB52吸收^22Na较N23232多,并较多地向根部运输。从离子再转运角度讨论了BB52的耐盐性。     

Influence of silicon on microdistribution of mineral ions in roots of salt-stressed barley as associated with salt tolerance in plants

Two contrasting barley (Hordeum vulgare L.) cultivars: Kepin No.7 (salt sensitive), and Jian 4 (salt tolerant) were grown hydroponically to investigate the microdistribution of mineral ions in roots as affected by silicon (Si) with respect to salt tolerance. The experiment was undertaken consisting of two treatments with 3 replicates: (i) 120 mmol · L⁻¹ NaCl alone (referred to as Si-NaCl+), (ii) 120 mmol · L⁻¹ NaCl + 1.0 mmol · L⁻¹ Si (as potassium silicate) (referred to as Si+NaCl+). Plant root tips were harvested for microanalysis using an energy dispersive X-ray microanalyzer (EDX) 30 d after transplanting. Higher Cl and Na X-ray peaks were recorded in the root epidermal, cortical and stelar cells of roots for the treatment Si-NaCl+ with the majorities of Na and Cl being accumulated in epidermal and cortical cells, while relatively low K peaks were observed regardless of the barley cultivars used. By contrast, considerably higher K peaks were detected in the epidermal, cortical and stelar cells of the roots for the treatment Si+NaCl+, but lower Cl and Na peaks were also observed for this treatment with both Na and Cl ions being evenly distributed in the epidermal, cortical and stelar cells. These findings directly support our previous finding, which showed that Si depressed the uptake of sodium but enhanced the uptake of potassium by salt-stressed barley. We believe that one of the possible mechanisms involved in Si-enhancement of salt tolerance in barley is attributed to the Si-induced changes in the uptake and microdistribution of mineral ions in plants.     

江苏野生大豆的耐盐性和离子在体内的分布及选择性运输

以相对发芽率和出苗率为指标比较了3个野生大豆(Glycine soja)种群的耐盐性,测定了NaCl胁迫下2个耐盐性不同的野生大豆种群(江苏野生大豆,JWS,耐盐;N23232,盐敏感)植株根、茎和叶片中Na^+、K^+和Cl^-含量的变化。结果表明,JWS的耐盐性最强,盐胁迫抑制野生大豆幼苗生长,使其干物质积累量减少,根冠比上升,对耐盐性弱的N23232抑制作用大于耐盐性强的JWS,不同器官离子含量测定结果表明,盐胁迫下野生大豆茎部Na^+含量最高,耐盐的JWS根系具有积累Na^+和Cl^-的能力,叶片Na^+、Cl含量较低,而盐敏感种群N23232根系中：Na^+、Cl^-含量低于耐盐种群JWS,叶片中Na^+、Cl^-含量则高于JWS,JWS根系对K^+、Na^+吸收的选择性(selectivity ratio,SK,Na)和N23232没有明显差异;但叶片和茎运输的SK,Na明显高于N23232,使地上部K^+／Na^+较高,因此认为野生大豆根系对Na^+、Cl^-的积累及K^+向地上部运输的选择性高是其耐盐性强的主要原因。     

Cell-specific localization of Na+ in roots of durum wheat and possible control points for salt exclusion

Sodium exclusion from leaves is an important mechanism for salt tolerance in durum wheat. To characterize possible control points for Na(+) exclusion, quantitative cryo-analytical scanning electron microscopy was used to determine cell-specific ion profiles across roots of two durum wheat genotypes with contrasting rates of Na(+) transport from root to shoot grown in 50 mm NaCl. The Na(+) concentration in Line 149 (low transport genotype) declined across the cortex, being highest in the epidermal and sub-epidermal cells (48 mm) and lowest in the inner cortical cells (22 mm). Na(+) was high in the pericycle (85 mm) and low in the xylem parenchyma (34 mm). The Na(+) profile in Tamaroi (high transport genotype) had a similar trend but with a high concentration (130 mm) in the xylem parenchyma. The K(+) profiles were generally inverse to those of Na(+). Chloride was only detected in the epidermis. These data suggest that the epidermal and cortical cells removed most of the Na(+) and Cl(-) from the transpiration stream before it reached the endodermis, and that the endodermis is not the control point for salt uptake by the plant. The pericycle as well as the xylem parenchyma may be important in the control of net Na(+) loading of the xylem.     

盐胁迫下沙棘的渗透调节效应

分别用含有0、100、200和300mmol LNaCl的Hoagland培养液处理1年生沙棘(HippophaerhamnoidesL.)苗30d后,测定其鲜重,干重,含水量,可溶性糖、脯氨酸和无机离子(Na 、Cl-)的含量及叶片渗透势和渗透调节能力。结果表明:100mmol LNaCl处理的沙棘地上部和根的鲜重和干重最大,其含水量也最大;NaCl浓度超过100mmol L时,沙棘地上部分和根的鲜重和干重随盐浓度增加而逐步下降,其下降的趋势为地上部大于根部。随NaCl浓度不断升高,沙棘体内Na 和Cl-浓度随之升高,茎叶和根系中Cl-含量明显高于Na ,对Na 的相对吸收量多于Cl-。沙棘对盐胁迫有一定的适应能力,随NaCl浓度的升高,沙棘叶内脯氨酸含量升高,可溶性糖含量增加,渗透势降低,渗透调节能力增强。本结果可为盐碱地营造沙棘林提供依据。     

REGULATION OF NaCl IN JAUMEA CARNOSA (ASTERACEAE), A SALT MARSH SPECIES,AND ITS EFFECT ON LEAF SUCCULENCE

A salt marsh species, Jaumea carnosa, was used in hydroponic experiments to test the effects of increasing NaCl concentrations on leaf succulence and plant accumulations of K, Ca, Mg, Na and Cl. A nested experimental design was used with four salinity levels. Plants were grown in full Hoagland's solution plus different amounts of NaCl (0.0–1.2 osmoles). Leaf succulence was measured as percent water content as well as vertical elongation of mesophyll cells. There were no corresponding increases in leaf succulence with increasing concentrations of NaCl in the root zone. Plants receiving aerosol spray (40 mg/dm²/day) did not show significant increases in leaf succulence. Leaf succulence was significantly increased when the plants were removed from the NaCl solutions and placed in non-salinized Hoagland's solution. Osmotic concentrations of cell sap in leaf tissues showed significant increases as NaCl concentrations increased in the root zone. The concentrations of K, Ca and Mg were higher in plants grown without NaCl than in those grown with NaCl. The accumulations of K in the root tissues were always higher than those of the shoot tissues. Although there was a two-fold difference in NaCl concentrations at the highest levels, the concentrations of Na in the shoot tissues were relatively similar. The results of the Cl analyses of shoot tissues showed a similar pattern of regulation of uptake. This regulation of salt uptake may be important in preventing injury by limiting accumulations of salt in plant tissues when growing in soils of high osmotic potentials.     

Salinity tolerance of citrus rootstocks: Effects of salt on root and leaf mineral concentrations

The effects of three concentrations of sodium chloride (NaCl) on seven citrus rootstocks were studied under greenhouse conditions. Leaf and root mineral concentrations and seedling growth were measured. Sodium chloride was added to the nutrient solution to achieve final osmotic potentials of –0.10, –0.20, and –0.35 MPa. Increasing the concentration of NaCl in the nutrition solution reduced growth proportionally and altered leaf and root mineral concentrations of all rootstocks. Significant differences in leaf and root mineral concentration among rootstocks were also found under stressed and non-stressed conditions. Salinity caused the greatest growth reduction in Milam lemon and trifoliate orange and the least reduction in sour orange and Cleopatra mandarin. No specific nutrient deficiency was the sole factor reducing growth and causing injury to citrus rootstocks. Sodium chloride sensitivity of citrus rootstocks in terms of leaf burn symptoms and growth reduction could be attributed more to Cl than to Na. Sodium and Cl concentrations were greater in the leaves than in the roots, particularly at the medium and high salinity levels. Root Cl was not useful for assessing injury because no differences were found in root Cl concentrations among rootstocks. Increasing salinity level did not affect the level of N and Ca in the roots but did reduce N and Ca levels in the leaves. No relationship in mineral concentration or accumulation seemed to exist between citrus leaves and roots. At the –0.10 MPa salinity level, sour orange, rough lemon, and Milam were not able to exclude either Na or Cl from their leaves. Trifoliate orange and its two hybrids (Swingle citrumelo and Carrizo citrange) excluded Na at the lowest salt level used, but were unable to exclude Na at the higher salinity levels. Similarly, Cleopatra mandarin excluded Cl at the lowest salt level, but was not able to exclude Cl at higher salt concentrations. Hence, the ability of citrus rootstocks to exclude Na or Cl breaks down at higher salt concentrations.Florida Agricultural Experiment Station Journal Series No. R-02276.