The influence of mycorrhizal inoculation and paclobutrazol on water and nutritional status of Arbutus unedo L.

The purpose of this study was to analyze morphological and physiological aspects of Arbutus unedo L. plants treated with paclobutrazol (PAC), compounds characterized by their double activity as plant growth regulators and fungicides, and the ectomycorrhizal fungus Pisolithus tinctorius (Pers.) Coker and Couch, which forms a special type of mycorrhizal colonization called arbutoid mycorrhiza. Native A. unedo L. seedlings were grown in a greenhouse and subjected to four treatments for 4 months: 0 or 60 mg of PAC and inoculated or not with P. tinctorius (Pers.). The arbutoid mycorrhizal inoculation increased in plants treated with PAC. Paclobutrazol reduced shoot and root biomass, plant height, internode length, stem diameter, leaf area, total root length and number of tips. P. tinctorius increased plant height and had a beneficial effect on the root system (increasing root diameter and the number of tips). PAC treatment led to an increase in ion levels in the leaf tissue, while mycorrhizal inoculation induced lower K and higher P contents in the roots. Leaf water potentials (at predawn and at midday) increased with the combined treatment. The absence of water deficit conditions meant there was no osmotic adjustment. Higher photosynthesis (P_n) values were associated with higher stomatal conductance (g_s) values in the mycorrhizal plants, which influenced water uptake from the roots. However, g_s decreased in the PAC-treated plants, reducing photosynthesis and, as a consequence, growth. The higher hydraulic conductivity (L_p) in the plants treated with PAC may have induced a better water energy status and good water transport. The combined treatment produced beneficial effects in the plants, improving their water and nutritional status.     

Growth rate, water relations and ion accumulation of soybean callus lines differing in salinity tolerance under salinity stress and its subsequent relief

A selected Glycine max (L.) salt-tolerant calluscell line (R100) was significantly more tolerant to salt than a salt-sensitiveline (S100) during exposure to salt stress. Growth (Fresh and Dry weights) ofthe R100 cell line declined significantly at NaCl concentrations greater than 75mM, while growth of the S100 cell line was already impaired at 25mM NaCl. Levels of Na⁺ and Cl^– inthe callus were elevated as the salt concentration increased, whileK⁺, Ca²⁺ and Mg²⁺ levels weremarkedly reduced. The lower s reduction and Na⁺accumulation found in the S100 callus corresponded with the higher callusdehydration during salinity. Calli grown on Miller's basal medium weresupplied with 100 mM NaCl for 12 days and then supplied with mediumwithout NaCl to relieve salinity stress. The Na⁺ andCl^– content decreased in both R100 and S100 cell lines duringthe first 24 h and reached normal levels four days after transferto the normal medium. This lower concentration was maintained until the end ofthe experiment. Concurrently, the K⁺ content andK⁺/Na⁺ ratio increased sharply and reached theirhighest levels within 24 h in both salt-sensitive and salt-tolerantcell lines. These data suggest that the inhibitory effects of salinization ongrowth and accumulation of potentially toxic ions (Na⁺,Cl^–) can be readily reversed when salinity is relieved.     

Growth and mineral accumulation in Eucalyptus camaldulensis seedlings irrigated with mixed industrial effluents

Effects of mixed industrial effluents on growth, dry matter accumulation and mineral nutrient in Eucalyptus camaldulensis seedlings were studied. The objective was to evaluate the adaptability of E. camaldulensis to effluent, tolerance to excess/deficiency of mineral elements and ultimately to determine suitable combinations of industrial/municipal effluent for their use in biomass production in dry areas. Different irrigation treatments were: T(1): good water; T(2): municipal effluent; T(3): textile effluent; T(4): steel effluent; T(5): textile effluent+municipal effluent in 1:1 ratio; T(6): steel effluent+municipal effluent in 1:2 ratio; T(7): steel+textile+municipal effluent in 1:2:2 ratio; and T(8): steel+textile effluent in 1:2 ratio. High concentrations of metal ions and low concentrations of Ca, Mg, K, Na, N and P in soil and seedlings of T(4) resulted in mortality of the seedlings within a few days. Addition of the textile/municipal effluent increased the survival time of the seedlings for two to three months in T(6), T(7) and T(8) treatments. Among the remaining treatments, the seedlings of T(2) attained 131 cm height, 1.97 cm collar diameter, 19 total branches and produced 158 g seedling(-1) of dry biomass at the age of 10 months. The seedling of T(3) produced the least growth and biomass. Growth equivalent to that of the seedlings of T(1) treatment was achieved when municipal effluent was mixed with textile effluent (T(5)). There was a decrease in soil pH, EC, SOC, NH(4)-N, NO(3)-N, PO(4)-P and basic cations and increase in the concentration of Cu, Fe, Mn and Zn with T(4) treatment. The reverse trend was observed in T(3) where a high concentration of Na might have reduced Mg and micronutrient concentration in seedlings potentially affecting root and leaf growth. Mixing of effluents may be useful in tree irrigation to increase biomass productivity, which is evidenced by improved growth in T(5) and survival in T(6), T(7) and T(8) treatments. Further, reduction of toxic concentration of metal ions in effluents may be helpful for a long-term field application.     

The control by atmospheric factors and water stress of midday stomatal closure in Arbutus unedo growing in a natural macchia

Summary Midday closure of stomata of well-watered ( between-10 and-25 bar) or moderately stressed ( between-25 and-35 bar) Arbutus unedo plants occurs when midday leaf temperatures increase above 30°C and vapor pressure difference between leaf air spaces and the external air increases above approximately 30 mbar/bar. Moderate water stress decreases maximum conductance and may result in greater sensitivity to high leaf temperature and vapor pressure dificit, which results in earlier closure and later reopening of stomata. Severe water stress ( of-50 bar) changes the form of the daily pattern observed for leaf conductance. A single morning peak in conductance occurs followed by decrease in conductance over the remainder of the day. Morning fog in Portugal during the dry season may facilitate stomatal opening and may allow improvement of carbon balances of the leaves for short periods, but contributes little to improvement of plant water balances over the longer term.     

Diurnal variations in abscisic acid content and stomatal response to applied abscisic acid in leaves of irrigated and non-irrigated Arbutus unedo plants under naturally fluctuating environmental conditions

Summary Endogenous abscisic acid content (ABA) of Arbutus unedo leaves growing under natural conditions in a macchia near Sobreda, Portugal, was very high (0.25 to 2.3 g g¹ fresh weight). Highest concentrations were found during the very early morning hours and at midday. During the late morning hours and in the late afternoon ABA concentrations decreased to between one-third and one-fourth of peak values. The samples for ABA content were obtained from both irrigated ( between-10 and-25 bar) and non-irrigated plants experiencing natural water stress during the dry season ( of-50 bar). During the course of the measurement day, stomatal conductance was relatively constant and conductance of watered plants was 50 to 100% greater than that of unwatered plants. No clear correlations between ABA content and stomatal conductance and/or xylem water potential were observed. Despite large differences in water potential and differences in degree of stomatal opening, absolute concentrations of ABA were not found to differ.Small quantities (8–14 pmoles cm² leaf area) of ABA were applied to leaves of irrigated and non-irrigated Arbutus unedo plants by injection into the petiole. These extremely small ABA doses resulted in transient reductions in stomatal conductance. The effectiveness with which injected ABA closed stomata was highest during the morning and decreased substantially at midday. Increased sensitivity to injected ABA may again occur in the late afternoon but recent measurements suggest that this may depend on long-term drought experience of the plants. The characteristics of the response to injected ABA were similar in irrigated and non-irrigated plants although irrigated plants responded in general more strongly.     

Effects of NaCl on growth, water status, N2 fixation, and ion distribution in Pterocarpus officinalis seedlings

Pterocarpus officinalis (Fabaceae) dominates in the swamp forests of the Lesser Antilles, submitted to strong variations of soil salinity (30–445 mM). This study aimed to assess the effect of salinity on growth, nodulation, N₂ fixation, water status and ions content in P. officinalis and to clarify the mechanisms involved. Seedlings inoculated or not with two strains from areas of contrasting salinity levels (< to 50 or 445 mM) were watered with 0, 171 and 342 mM solutions of NaCl in greenhouse conditions. Non-inoculated seedlings were tolerant to a salinity of 171 mM, with no significant effect on seedling biomass. Evapotranspiration per unit of leaf area (E/TLa) remained unchanged at 171 mM. Maintenance of a constant E/TLa and especially the control of ion transport to the upper parts of the plant could explain seedling salt tolerance up to intermediate salinity conditions (171 mM). The two strains have a 99.8% genetic identity in spite of differences in their original habitats, this explaining the similar response of the symbiosis to salinity. The higher salt sensitivity of inoculated seedlings was linked to the sensitivity of both Bradyrhizobium strains (reduction of free-living cells) and to that of the nodulation process (fewer nodules and inhibition of N₂-fixation) to intermediate salinity.     

Growth and ion accumulation in Salicornia europaea under saline field conditions

Summary The relationship between the distribution and growth of Salicornia europaea and soil conditions was studied on an inland saline marsh. Data were collected concerning plant growth, ion content, and water potential of S. europaea throughout the growing season to determine how these responses were related to soil-ionic content, electrical conductivity, and water potential. Soil salinity concentration was the factor most highly correlated with plant growth, survival and ionic content of organs of S. europaea.This research was supported in part by NSF research grant DEB 7927236. We thank the Morton Salt Company for allowing us to carry out these investigations at Rittman, Ohio     

Balanced Gene Losses,Duplications and Intensive Rearrangements Led to an Unusual Regularly Sized Genome in Arbutus unedo Chloroplasts

Completely sequenced plastomes provide a valuable source of information about the duplication, loss, and transfer events of chloroplast genes and phylogenetic data for resolving relationships among major groups of plants. Moreover, they can also be useful for exploiting chloroplast genetic engineering technology. Ericales account for approximately six per cent of eudicot diversity with 11,545 species from which only three complete plastome sequences are currently available. With the aim of increasing the number of ericalean complete plastome sequences, and to open new perspectives in understanding Mediterranean plant adaptations, a genomic study on the basis of the complete chloroplast genome sequencing of Arbutus unedo and an updated phylogenomic analysis of Asteridae was implemented. The chloroplast genome of A. unedo shows extensive rearrangements but a medium size (150,897 nt) in comparison to most of angiosperms. A number of remarkable distinct features characterize the plastome of A. unedo: five-fold dismissing of the SSC region in relation to most angiosperms; complete loss or pseudogenization of a number of essential genes; duplication of the ndhH-D operon and its location within the two IRs; presence of large tandem repeats located near highly re-arranged regions and pseudogenes. All these features outline the primary evolutionary split between Ericaceae and other ericalean families. The newly sequenced plastome of A. unedo with the available asterid sequences allowed the resolution of some uncertainties in previous phylogenies of Asteridae.     

盐胁迫对桑树幼苗生长、叶片水分状况和离子分布的影响

以黑龙江省两个桑树品种（秋雨桑和泰来桑）为试验材料,研究了不同盐浓度下桑树幼苗生长、叶片水分关系和不同器官中离子的分布.结果表明：盐胁迫明显降低了桑树幼苗的植株高度和每株干物质量,且对新生叶片干质量的影响大于老叶片.随着盐胁迫的加重,两个品种桑树的叶片水势、渗透势、压力势和相对含水量明显下降,根、茎中Na⁺浓度明显增加,当外界NaCl浓度达到或超过150 mmol·L^-1时,各器官中Na⁺浓度达到饱和.盐胁迫明显降低了两个品种桑树根、茎和叶片中K⁺ 和 Ca²⁺浓度,以及茎和叶片中Mg²⁺浓度,而对根中Mg²⁺浓度影响不大.Na⁺在根、茎和老叶中的区域化分布是两个品种桑树生长过程中表现出耐盐性的机理之一,而盐胁迫使叶片中的Ca²⁺、K⁺和Mg²⁺浓度降低,导致植株体内的离子亏缺,从而限制了植株的生长.     

Brief pre- and post-irrigation sprinkling with fresh water reduces foliar salt uptake in maize and barley sprinkler irrigated with saline water

Brief pre- and post-irrigation sprinkling treatments using freshwater were tested to determine if these practices could reduce the uptake of salts through leaves when saline water is used to sprinkler irrigate crops. Maize and barley were sprinkler irrigated 2 to 3 times per week for 30 min with saline water (4.2 dS m^–1, 30 mmol L^–1 NaCl and 2.8 mmoles L^–1 CaCl₂ for maize and 9.6 dS m^–1, 47 mmoles L^–1 NaCl and 23.5 mmoles L^–1 CaCl₂ for barley) in separate experiments with plants grown in pots outdoors. The soil surface of all pots was covered to prevent salinization of the soil by the sprinkling water. One half of the sprinkled plants was grown in nonsaline soil to study the effects of pre-wetting and post-washing when ion uptake was primarily through leaves. The other half of the sprinkled plants was grown in soil salinized by drip irrigation, in order to evaluate the effects of pre-wetting and post-washing when Na⁺ and Cl^- uptake was through both leaves and roots.Post-washing with freshwater (5 min) reduced the leaf sap concentrations of Cl^- in saline-sprinkled plants from 56 to 43 mmol L^–1 in maize and from 358 to 225 mmol L^–1 in barley (averages for plants grown in nonsaline and saline soil). Na⁺ concentrations in leaf sap were reduced from 93 to 65 mmoles L^–1 (maize) and from 177 to 97 mmoles L^–1 (barley) by the post-washing. Pre-wetting had a small effect on ion uptake through leaves, the only significant reduction in seasonal means being in leaf Na⁺ concentrations for plants grown in nonsaline soil. Pre-wetting and post-washing, when combined, reduced leaf Cl^- concentrations to levels similar to those of nonsprinkled plants grown in saline soil; however, Na⁺ concentrations in leaves remained 3.5 times (maize) and 1.5 times (barley) higher than those of nonsprinkled plants. When pre-wetting and post-washing were not applied, sprinkled barley plants grown in saline soil had grain yields which were 58% lower than nonsprinkled plants grown in saline soil, but the reduction in grain yield was only 17% when the freshwater treatments were given. We conclude that a brief period of post-washing with freshwater is essential when saline water is employed in sprinkler irrigation. By comparison, the benefits from pre-wetting were small in these experiments. ei]T J Flowers     

Growth, gas exchange and ion content in Olea europaea plants during salinity stress and subsequent relief

Olive ( Olea europaea L. cv. Frantoio) plants grown hydroponically in a glasshouse were supplied with half-strength Hoagland solutions containing 0, 50, 100, and 200 m M NaCl for 4 weeks and subsequently supplied with the standard solution without NaCl to relieve salinity stress. Two complete stress-relief cycles were repeated on the same plant material during one growing season. Growth was inhibited at all salt levels, but most growth parameters of plants treated with 50 or 100 m M NaCl returned to control levels after 4 weeks of relief. More severely stressed plants (200 m M NaCl) recovered to only 60% of the growth of the controls after 4 weeks. During relief, plants treated with 50 and 100 m M NaCl had net photosynthetic rates and stomatal conductances higher than the controls. Increasing the NaCl concentration of the external solution from 0 to 200 m M decreased both leaf pre-dawn water potential (from -0.3 to -1.0 MPa) and osmotic potential (from -2.1 to -2.7 MPa). The sodium concentration in the leaves of plants treated with 200 m M NaCl reached maximum levels of 211 and 388 m M (expressed on a tissue water basis) at the end of the first salinity and relief periods, respectively. Leaf chloride concentrations were 359 and 223 m M at the same sampling dates. These data indicate that the inhibitory effects of salinization on growth and gas exchange of the salt-tolerant olive cv. Frantoio can be readily reversed when salinity is relieved, despite the marked accumulation of potentially toxic ions (Na⁺. Cl) in the leaf.     

Arsenic uptake and accumulation in rice (Oryza sativa L.) irrigated with contaminated water

Long-term use of arsenic contaminated groundwater to irrigate crops, especially paddy rice (Oryza sativaL.) has resulted in elevated soil arsenic levels in Bangladesh. There is, therefore, concern regarding accumulation of arsenic in rice grown on these soils. A greenhouse pot experiment was conducted to evaluate the impact of arsenic-contaminated irrigation water on the growth and uptake of arsenic into rice grain, husk, straw and root. There were altogether 10 treatments which were a combination of five arsenate irrigation water concentrations (0–8 mg As l^–1) and two soil phosphate amendments. Use of arsenate containing irrigation water reduced plant height, decreased rice yield and affected development of root growth. Arsenic concentrations in all plant parts increased with increasing arsenate concentration in irrigation water. However, arsenic concentration in rice grain did not exceed the maximum permissible limit of 1.0 mg As kg^–1. Arsenic accumulation in rice straw at very high levels indicates that feeding cattle with such contaminated straw could be a direct threat for their health and also, indirectly, to human health via presumably contaminated bovine meat and milk. Phosphate application neither showed any significant difference in plant growth and development, nor in As concentrations in plant parts.     

Acclimatization and subsequent gas exchange, water relations, survival and growth of microcultured apple plantlets after transplanting them in soil

Wounded tuber tissue of potato ( Solanum tuberosum L. cv. Gloria) exposed to the monoterpene S-carvone did show neither suberization nor cambium layer formation, whereas these processes started after 2–4 days in control tissue. Suberized tissue was clearly visible 24 days after the start of the S-carvone treatment, when the concentrations of S-carvone and its bioconversion products in the tissue were almost zero and cambium layer formation had not yet started. The inhibition of wound healing coincided with a lack of induction of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR, EC 1.1.1.34). The wounded potato tissue used as control, showed a transient induction of HMGR activity.
In S-carvone treated tissue, the activities of GR (glutathione reductase, EC 1.6.4.2) and AP (ascorbate peroxidase, EC 1.11.1.11) were induced, and the level of glutathione increased four- to five-fold.     

咸水滴灌下塔里木沙漠公路防护林土壤生化作用强度及微生物生态特征

土壤生化作用强度是表征土壤生物学活性的重要指标。选择传统研究方法,从氨化作用、硝化作用、固氮作用、纤维素分解、呼吸作用以及酶活性6个方面,揭示了咸水滴灌下塔里木沙漠公路防护林地土壤生化作用强度的分异规律。结果表明,(1)随防护林定植年限的增大,土壤氨化作用、固氮作用、纤维素分解和呼吸作用的强度均明显增强,其中氨化作用和呼吸作用变化尤为明显;而硝化作用强度有所减弱。(2)0—50 cm土体内,随土壤深度增大,生化作用强度提高,氨化作用、硝化作用、固氮作用、纤维素分解和呼吸作用强度的垂直差异均达极显著水平(FF0.01)。(3)随防护林定植年限的增大,不同土壤酶活性的变化各异,其中,过氧化氢酶活性显著增大(FF0.01),纤维素酶和蔗糖酶的活性明显提高(FF0.05),而蛋白酶、磷酸酶和脲酶的活性变化不大(FF0.05)。(4)回归分析表明,不同生化强度因子与土壤环境因子的最优回归方程不同,但决定系数均大于0.95;全盐、全氮和速效氮进入了所有回归方程,是决定塔里木沙漠公路防护林地土壤生化强度的关键土壤环境因子。因此,咸水滴灌条件下,塔克拉玛干沙漠腹地防护林土壤生化作用强度不断提高的趋势,这对于防护林工程的科学管理有重要指示意义。     

Effect of salinisation of soil on growth, water status and general nutrient accumulation in seedlings of Delonix regia (Fabaceae)

Greenhouse experiments were conducted to assess the effect of salinisation of soil on emergence, growth, water content, proline content and mineral accumulation of seedlings of Delonix regia (Hook.) Raf. (Fabaceae). Sodium chloride (NaCl) was added to the soil and salinity was maintained at 0.3, 1.9, 3.9, 6.0 and 7.9 dS m⁻¹. A negative relationship between seedling emergence and salt concentration was obtained. Salinity caused reduction in water content and water potential of tissues (leaves, stems, tap roots and lateral roots) that resulted in internal water deficit to plants. Consequently, shoot and root elongation, leaf expansion and dry matter accumulation in leaves, stems, tap roots and lateral root tissues of seedlings significantly decreased in response to increasing concentration of salt. Proline content in tissues was very low. There were no effective mechanisms to control net uptake of Na on root plasma membrane and subsequently its transport to shoot tissues. Potassium content significantly decreased in tissues in response to salinisation of soil. This tree species is a moderate salt-tolerant glycophytic plant. Nitrogen and calcium content in tissues significantly decreased as soil salinity increased. Phosphors content in tissues exhibited a declining trend with increase in soil salinity. Changes in tissues and whole-plant accumulation pattern of other elements tested, as well as possible mechanisms for avoidance of Na toxicity in this tree species in response to salinisation, are discussed.     

Consecutive seasonal effect on yield and water productivity of drip deficit irrigated sorghum in saline soils

Drought stress destructively affects the growth and productivity of sorghum crop, especially under saline soils. Therefore, Field trials were performed to determine the influence of water stress on water productivity (water productivity for grain, (G-WP) and water productivity for forage, (F-WP), yield of sorghum and soil properties in salt-affected soil (8.20 dS m^?1) under different sowing dates and irrigation regimes. The summer sowing (SS) was performed on 1 April while fall sowing (FS) was established on 2 August. The irrigation regimes were; 100, 90, 80, and 70% of crop evapotranspiration (ETc). The findings displayed that the fodder and grain yields were increased by 23% and 26% under SS compared to FS over the two seasons 2017 and 2018, respectively. Among irrigation levels, the maximum values of grain and fodder yield were given by 100% of ETc, while a non-significant difference was observed between 100% and 90% of ETc. Moreover, the maximum values of G-WP (1.31%) and F-WP (9.00%) were recorded for 90% of ETc. Interestingly, the soil salinity was decreased in 0–0.6 m depth, and more decline was noted in 0–0.2 m depth using 90% of ETc. The highest salt accumulation withinside the soil profile was recorded under 70% of ETc in comparison to 100% of ETc. Thereupon, under water scarcity, application of 90% of ETc is recommended with SS to save 10% of the applied irrigation water without a significant decrease in grain yield (GY).     

Salinity effects on the leaf water relations components and ion accumulation patterns in Avicennia germinans (L.) L. seedlings

Physiological traits involved in leaf water relations were evaluated in Avicennia germinans (L.) L. seedlings growing at different salinities in the field. Analysis of pressure-volume (P-V) curves and sap osmometry were combined to evaluate osmotic adjustment and cell elasticity, and the contribution of accumulated inorganic ions to osmotic potential was estimated. Seedlings growing in soils with interstitial water salinity above that of normal sea water showed a modification of the relationship between water potential and relative water content. Thus, their leaf osmotic potential at maximum turgor (Ψ_{π( max )}) and at zero turgor (Ψ_π(0)) was 1.41 and 1.82 MPa lower respectively, than that of the seedlings from the low salinity site. Volumetric moduli of elasticity () were between 17 and 23 MPa. Thus, ɛ was about 6 MPa lower in high-salinity plants indicating that their cells were slightly more elastic. Ionic concentration analysis showed that Σ [anions] and Σ [cations] were higher in the high-salinity site (22–35%) while the water content per unit dry mass was only 12–17% lower. Reduction in water content was insufficient to explain the increase in ion concentration. Ion concentration explained 73 and 66% of the osmotic potential estimated by P-V curves for leaves from low- and high-salinity sites, respectively. In conclusion, this study provided evidence that leaves of A. germinans seedlings adapt to hypersaline soils by increasing solute concentration by 52% and cell elasticity by 26%. Both processes allow leaf water uptake and turgor maintenance over a large range of soil water potential. Received: 30 June 1997 / Accepted 26 November 1997     

Ionic relations and proline accumulation in shoots of two Chinese Iris germplasms during NaCl stress and subsequent relief

Adaptation to salinity in plant includes not only their response to stress, but also their ability to recover from it. Seeds of Chinese Iris (Iris lactea var. chinensis) collected randomly from an arid area in inland province of Xinjiang (Xj, E93°30^??, N42°48^??, 740?m), and a semi-arid coastal area in Beijing Municipality (Bj, N40°34^??, E116°10^??, 540?m) were studied. The objectives were to determine differences between germplasms in ionic relations or accumulation of proline in the shoots and establish how I. lactea adapts to salt stress and subsequent relief. Hydroponically-grown seedlings of the two germplasms were supplied with nutrient solutions containing 0.1 (control), 140 and 280?mM NaCl for 12?days, and supplied subsequently with a non-saline control solution for 12?days to relieve NaCl stress. Germplasm Xj had larger shoot mass and shoot/root ratio than Bj during stress and recovery periods. Salinity, even subsequent recovery, more adversely affected the water content in Bj than Xj. Under identical provision of treatments, the Xj maintained relatively higher K⁺/Na⁺ ratio and selectivity for transportation of K⁺ over Na⁺ than Bj. Additionally, we observed a slight proline accumulation in shoots of Bj, but its content was insufficient for lowering the solute potential. Germplasm Xj exhibits better adaptation to salinity and subsequent recovery. This is mainly due to its higher selectivity for transporting K⁺ over Na⁺. Proline accumulation did not play a key role the osmotic adjustment of the two I. lactea germplasms studied.     

Oil content and lipid composition of safflower (Carthamus tinctorius) irrigated with saline water under greenhouse and field conditions

An intensive process of land deterioration of some regions in Uzbekistan including the Aral Sea basin has led to a significant increase in soil salinity levels and consequently to a considerable reduction of total fertile soil area, as these lands are of little use for plant growth. The area is estimated to be more than 1.4 million ha of seabed. As a result, there was an immediate need to cultivate new crops capable of stopping the movement of sands and the enlargement of saline soils. Safflower (Carthamus tinctorius) is considered to be a moderately salt‐tolerant crop and, as such, one of a few crops well suited to the cropping systems of salt‐affected soils. It is used in Uzbekistan as a reserve crop when the culture of the main crop fails. In spite of the great economic importance of this oil, there is almost no available information in the literature on the effect of salinity on oil quality and its chemical ingredients. The purpose of the present study was to determine, in greenhouse and field experiments, how irrigation with saline water would influence content of oil, lipids and other lipophylic components in safflower. We found that irrigation of safflower with moderate concentrations of saline water seems feasible, as far as oil and lipid composition is concerned. Consequently, safflower might be a potential crop for lands of little use for plant growth in Uzbekistan or other similar sites in the world.     

Effect of salinisation of soil on growth, water status and general nutrient accumulation in seedlings .of Delonix regia (Fabaceae)

Greenhouse experiments were conducted to assess the effect of salinisation of soil on emergence, growth, water content, proline content and mineral accumulation of seedlings of Delonix regia (Hook.) Raf. (Fabaceae). Sodium chloride (NaCl) was added to the soil and salinity was maintained at 0.3, 1.9, 3.9, 6.0 and 7.9 dS m^?1. A negative relationship between seedling emergence and salt concentration was obtained. Salinity caused reduction in water content and water potential of tissues (leaves, stems, tap roots and lateral roots) that resulted in internal water deficit to plants. Consequently, shoot and root elongation, leaf expansion and dry matter accumulation in leaves, stems, tap roots and lateral root tissues of seedlings significantly decreased in response to increasing concentration of salt. Proline content in tissues was very low. There were no effective mechanisms to control net uptake of Na on root plasma membrane and subsequently its transport to shoot tissues. Potassium content significantly decreased in tissues in response to salinisation of soil. This tree species is a moderate salt-tolerant glycophytic plant. Nitrogen and calcium content in tissues significantly decreased as soil salinity increased. Phosphors content in tissues exhibited a declining trend with increase in soil salinity. Changes in tissues and whole-plant accumulation pattern of other elements tested, as well as possible mechanisms for avoidance of Na toxicity in this tree species in response to salinisation, are discussed.