The role of a plant/fungal consortium in the degradation of bituminous hard coal

The sporadic growth of Cynodon dactylon was observed to occur directly on the surface of hard coal in dumps of the Witbank coal mining area of South Africa with the surface coal being broken down into a humic-like particulate material. Microorganism analysis of plants and rhizosphere material from the dumps revealed the presence of arbuscular mycorrhizal fungi and the coal solubilising fungus, Neosartorya fischeri. Studies established to replicate the dump environment revealed increased coal degradation in the form of humic acid production and an increase in small size particles as a result of Cynodon dactylon growth in association with arbuscular mycorrhizal fungi and Neosartorya fischeri. Results suggest that interactions between Cynodon dactylon, arbuscular mycorrhizal fungi, Neosartorya fischeri and other coal-degrading rhizosphere fungi could lead to the degradation of hard coal in situ and that the application of these organisms to discard dumps could be a novel method of coal dump rehabilitation.     

Chemical forms of plant and soil iron as influenced by soil moisture

Summary Experiments were conducted to determine whether soil moisture content has an effect on the chemical forms of plant and soil iron. Soybean plants, variety Lee, were grown on Adelanto loam soil under greenhouse conditions. Two different moisture levels, 75 per cent and 120 per cent of the moisture equivalent, were maintained in soil samples placed in individual containers. The same moisture treatments were used for separate soil samples on which the test plants were grown.Soil iron forms were determined in the moisture-treated soil by using different extracting agents. A significant decrease in soil iron extracted with 10^–4 M EDTA from soil at the high moisture level was attributed to a relative increase in the free calcium ion.Soybean plants grown under the high moisture level were chlorotic while those under the low moisture level were green in appearance. Plant samples were taken at two stages of growth for subsequent analysis.The chemical analysis of the leaf tissues have shown the presence of equal amounts of total iron and less amounts of water-soluble and active iron in chlorotic tissues as compared to non-chlorotic tissues. The difference found between chlorotic and non-chlorotic plants in the amount of iron in the water extract was in the trichloroacetic acid-soluble fraction. The water- and salt-soluble protein nitrogen was approximately the same in chlorotic and non-chlorotic leaves.     

Effect of Iron Deficiency Induced Changes on Photosynthetic Pigments,Ribulose-1,5-Bisphosphate Carboxylase,and Photosystem Activities in Field Grown Grapevine (Vitis Vinifera L. cv. Pinot Noir) Leaves

The effect of iron deficiency on photosynthetic pigments, ribulose-1,5-bisphosphate carboxylase (RuBPC), and photosystem activities were investigated in field grown grapevine (Vitis vinifera L. cv. Pinot noir) leaves. The contents of chlorophyll (Chl) (a+b) and carotenoids per unit fresh mass showed a progressive decrease upon increase in iron deficiency. Similar results were also observed in content of total soluble proteins and RuBPC activity. The marked loss of large (55 kDa) and small (15 kDa) subunits of RuBPC was also observed in severely chlorotic leaves. However, when various photosynthetic electron transport activities were analysed in isolated thylakoids, a major decrease in the rate of whole chain (H₂O methyl viologen) electron transport was observed in iron deficient leaves. Such reduction was mainly due to the loss of photosystem 2 (PS2) activity. The same results were obtained when F_v/F_m was evaluated by Chl fluorescence measurements in leaves. Smaller inhibition of photosystem 1 (PS1) activity was also observed in both mild and severely chlorotic leaves. The artificial electron donors, diphenyl carbazide and NH₂OH, markedly restored the loss of PS2 activity in severely chlorotic leaves. The marked loss of PS2 activity was evidently due to the loss of 33, 23, 28-25, and 17 kDa polypeptides in iron deficient leaves.     

The effect of calcium bicarbonate on iron absorption and distribution byChrysanthemum morifolium, (Ram.)

Summary Plants grown for two weeks in high-bicarbonate nutrient solution with iron became chlorotic, absorbed less iron, and translocated a lower percentage of absorbed iron than did green plants grown under low bicarbonate with iron. Chlorotic plants, pretreated in low-bicarbonate solutions lacking iron, absorbed more iron and translocated a higher percentage to leaves than the green plants. Plants induced to chlorosis by high bicarbonate absorbed less iron after transfer to low-bicarbonate solution containing iron than did chlorotic plants pretreated with low-carbonate solution lacking iron. Initial localization of iron occurred in the roots. A considerable amount of the iron initially found on the roots was translocated to developing shoots over a nine-week period unless the plants were grown in high bicarbonate solutions. More iron was translocated from roots of plants in minus-iron solutions following initial absorption than when iron was supplied in the nutrient solutions. Journal Series Paper736. University of Georgia, College of Agriculture Experiment Stations, College Station, Athens, Ga. 30601.     

Growth of maize plants in flowing medium with different levels of iron

The flow of the nutrient solution stimulates significantly the growth of maize plants and enhances the absorption of nitrogen, potassium, and phosphorus. Especially the content of phosphorus in the shoots and in the roots is significantly increased, but its incorporation into organic compounds is considerably decreased. The plants grown, in flowing nutrient solutions have an altered distribution of iron with a higher amount of it remaining in the roots. In the shoots there is an increase in the P/Fe ratio, the ratio between ions changes in all parts of the plants in disfavour of N, K, and Fe, the production of dry matter is higher and the synthesis of chlorophyll is inhibited.     

Responses of Arabidopsis thaliana to bicarbonate-induced iron deficiency

Morpho-physiological and biochemical responses of Arabidopsis thaliana (accession N1438) to bicarbonate-induced iron deficiency were investigated. Plants were grown in cabinet under controlled conditions, in a nutrient solution containing 5 μM Fe, added or not with 10 mM NaHCO₃. After 30 days, bicarbonate-treated plants displayed significantly lower biomass, leaf number and leaf surface area as compared to control plants, and slight yellowing of their younger leaves was observed. Potassium (K⁺) content was not modified by bicarbonate treatment in roots, whereas it was significantly diminished in shoots. Their content in ferrous iron (Fe²⁺) and in leaf total chlorophylls was noticeably lower than in control plants. Root Fe(III)-chelate reductase and phosphoenolpyruvate carboxylase (PEPC) activities were significantly enhanced, but leaf ribulose 1.5-bisphosphate carboxylase (Rubisco) activity was decreased.     

Photosynthetic carbon fixation in iron-chlorotic and recovered green sugarcane leaves

Summary Sugarcane var. Co 740 is grown in various parts of Maharashtra (India) and is susceptible to chlorosis due to physiological non-utilization of iron. The physiological disorder is seen over a large area and it results in poor yield. Low sucrose yield can be recovered by foliar sprays of ferrous sulphate. The nonchlorotic and chlorotic leaves were used for the photosynthetic studies. The leaves after ferrous sulphate treatment show an increase in total chlorophyll contents and at the same time show an improved chlorophylla to chlorophyllb ratio which is affected in the chlorotic ones. The recovered green leaves have higher uptake of nitrogen, phosphorus, potassium and iron.¹⁴CO₂ fixation studies for short- and long-term experiments reveal that recovered green leaves can synthesize malate more efficiently and also utilize it for sucrose synthesis more rapidly than in the chlorotic ones. On the contrary more amino acids, reducing sugars and sugar phosphates are synthesized in the chlorotic leaves. There is also an accumulation of citrate, glutamate, and tartrate in the chlorotic leaves. Our results indicate that sucrose synthesis is disturbed in the chlorotic leaves and can be corected byfolia: sprays of ferrous sulphate.     

Decomposition of Cynodon dactylon (L.) Pers. in the seasonally flooded areas of the Pongolo river floodplain: pattern and significance of dry matter and nutrient loss

Cynodon dactylon meadows occupying seasonally inundated areas of the Pongolo river floodplain, South Africa, decompose during periods of submergence. The loss of dry matter and nutrients from both fresh and dried material enclosed in litter bags was studied. The pattern of loss of dry matter was diphasic. Loss was more rapid from dried than from fresh material, half the mass being lost in 18 and 28 days respectively. Nutrient loss followed an exponential pattern. Nitrogen, phosphorus and magnesium were lost more rapidly from dried than from fresh material whilst rates of loss of sodium, potassium and calcium were similar. The significance of Cynodon decomposition in the functioning of the floodplain is assessed from estimates of the above- and below-ground standing crop around one small lake before and after submergence. It is concluded that decomposition of plants growing in seasonally inundated areas of the floodplain may contribute significantly to the productivity of the system, but that the extent of the contribution can be greatly influenced by the flooding regime. The completion of the Pongolapoort dam upstream of the floodplain will alter the natural flooding pattern, effecting a reduction in floodplain productivity, unless a programme for flood release can be initiated.     

Effect of excess water in an oxisol on ammonium,nitrate, iron and manganese availability and nutrient uptake of two tropical forage species

Summary A glasshouse experiment was conducted to determine how reduction conditions would affect plant nutrient availability and uptake in a red-yellow latosol (Acrustox). Soil analysis showed that the most important changes were a marked increase in extractable iron and an inhibition of nitrification. The grass andropogon (Andropogon gayanus Kunth var.bisquamulatus (Hoechst) Hack) and the legume stylo (Stylosanthes capitata (Vog)) responded differently to reducing conditions.Andropogon showed low P, Ca, Mg, Fe and Mn content in the shoots but an intense coating of oxidized iron was observed on the surface of roots. Stylo plants, on the other hand, showed no iron deposition on the root surfaces but a high iron content in the shoots. No decreased P, Ca or Mg content was observed in this case. It was concluded that in water saturated soil, reduction took place and plant performance was affected not only by restricted root development but by preventing P, Ca and Mg uptake in andropogon and increasing Fe uptake in stylo plants. It is suggested that restricted P, Ca and Mg uptake by andropogen would be the result of iron deposition on root surfaces.     

Study of the relationship between the content of the rare earth element Eu in rice plants and in Nilaparvata lugens (Hemiptera: Delphacidae)

Abstract The current study investigated changes in the content of the rare earth element Europium (Eu) in roots, shoots and leaves of rice plants and in Nilaparvata lugens Stål (Hemiptera: Delphacidae) using an Eu marker and hydroponic culture. The results showed that N. lugens infestation significantly reduced Eu content in roots, shoots and leaves of two rice varieties, Shenyou 1 and Xieyou 963. The Eu content in roots, shoots and leaves of the susceptible variety, Shenyou 1, was significantly higher than that in the resistant variety, Xieyou 963. The Eu content of N. lugens fed on Shenyou 1 was significantly higher than of those fed on Xieyou 963. In addition, the Eu level was elevated at a higher density of N. lugens infestation. Eu content in the bodies of N. lugens was related to their weight and honeydew excretion, with a significant positive correlation. Thus, Eu content in the bodies of N. lugens can be considered an index of the amount of phloem sap taken in by N. lugens because the amount of honeydew excretion is proportional to the amount of phloem sap consumed. The ratios of Eu content in N. lugens to that in roots, shoots and leaves of rice plants were elevated at a higher N. lugens infestation density. That ratio was maximal in leaves, was intermediate in shoots and was minimal in roots. There was no significant difference in ratios between the two plant varieties. An Eu marker may be useful in the screening of resistant varieties and in the study of the mechanisms of resistance.     

1-Aminocyclopropane-1-Carboxylic Acid Transported from Roots to Shoots Promotes Leaf Abscission in Cleopatra Mandarin (Citrus reshni Hort. ex Tan.) Seedlings Rehydrated after Water Stress

The effect of water stress and subsequent rehydration on 1-aminocyclopropane-1-carboxylic acid (ACC) content, ACC synthase activity, ethylene production, and leaf abscission was studied in Cleopatra mandarin (Citrus reshni Hort. ex Tan.) seedlings. Leaf abscission occurred when drought-stressed plants were allowed to rehydrate, whereas no abscission was observed in plants under water stress conditions. In roots of water-stressed plants, a high ACC accumulation and an increase in ACC synthase activity were observed. Neither increase in ACC content nor significant ethylene production were detected in leaves of water-stressed plants. After rehydration, a sharp rise in ACC content and ethylene production was observed in leaves of water-stressed plants. Content of ACC in xylem fluid was 10-fold higher in plants rehydrated for 2 h after water stress than in nonstressed plants. Leaf abscission induced by rehydration after drought stress was inhibited when roots or shoots were treated before water stress with aminooxyacetic acid (AOA, inhibitor of ACC synthase) or cobalt ion (inhibitor of ethylene-forming enzyme), respectively. However, AOA treatments to shoots did not suppress leaf abscission. The data indicate that water stress promotes ACC synthesis in roots of Cleopatra mandarin seedlings. Rehydration of plants results in ACC transport to the shoots, where it is oxidized to ethylene. Subsequently, this ethylene induces leaf abscission.     

三峡库区消落带4种典型草本植物的生态化学计量特征

为研究三峡水库消落带优势植物的养分利用特征及其对生境的适应策略,选择消落带分布最多的4种草本植物为研究对象,分析了植物根、茎、叶的碳(C)、氮(N)、磷(P)、钾(K)含量和化学计量比特征。结果表明:(1)相比陆地系统和自然湿地系统,消落带植物具有较低的C含量和较高的N、P、K含量,C/N、C/P、C/K均较低,表明植物具有低固碳和高养分积累、低养分利用效率和高生长速率的特征;(2)4种植物的养分含量和计量比存在一定差异,其中狗牙根具有较低的N、P、K含量和较高的C/N、C/P、C/K,且变异系数均低于其他3种植物,其低养分需求、高养分利用效率以及较强的内稳性可能是其在库区分布最广的重要机制;(3)4种植物在不同器官的养分分配策略相似,均表现为叶片C含量低于根和茎,而N、P、K含量则显著高于根、茎;同时,与根、茎相比,叶片C/N、C/P、C/K较低,N/P、N/K较高,且在不同生境条件下变异系数较小,表现出相对较高的稳定性;(4)落消带植物的养分含量及计量比从全库区上游至下游的空间变异性较强,其中N、C/N、N/P变异性较大,而C、P、K变异性较小,表明植物N含量受生境变化的影响较大,...     

Metabolic Changes Associated with the Sink-Source Transition During Sprouting of the Axillary Buds on the Sugarcane Culm

Sucrose, glucose and fructose concentrations, and sucrolytic enzyme activities were measured in the developing shoots and internodes of sprouting sugarcane setts (Saccharum spp, variety N19). The most striking change during the sink-source transition of the internode and germination of the axillary bud is a more than five-fold induction of cell wall invertase in the germinating bud. In contrast, soluble acid invertase is the main sucrose hydrolytic activity induced in the internodal tissue. A cycle of breakdown and synthesis of sucrose was evident in both the internodes and the shoots. During shoot establishment, the sucrose content decreased and the hexose content increased in the internodal tissues while both sucrose and hexoses continuously accumulated in the shoots. Over the sprouting period internode, dry mass was reduced by 25 and 30 % in plants incubated in a dark/light cycle or total darkness, respectively. Sucrose accounted for 90 % of the dry mass loss. The most significant changes in SuSy activity are in the synthesis direction in the shoots resulting in a decrease in the breakdown/synthesis ratio. In contrast the SuSy activity in the internodal tissue decrease and more so in the synthesis activity resulting in an increase in the breakdown to synthesis ratio.     

Studies in the Nutrition of Apple Rootstocks The Effect on Growth and Mineral Composition of Supplying Iron Through the Leaves

Apple rootstocks were grown with either 0.02 ppm Fe (Fe₀) or5 ppm (Fe₃), to give very chlorotic or dark-green plants. Toinvestigate whether iron can be supplied through leaves insteadof roots the shoots of half the plants in each treatment weredipped periodically in solutions of iron. This prevented chlorosisin Fe₀ plants and increased their growth, which did not, however,equal that of Fe₃ plants supplied with iron through the roots.Growth of Fe₃ plants was reduced by dipping. Iron was not translocated from leaves to roots, although theconcentration in leaves was greatly increased by dipping. Dippingreduced the amount of manganese in Fe₀ roots to one-quarterof that in roots of undipped Fe₀ plants. Effects of treatmentson nitrogen, potassium, calcium, magnesium, and copper levelsare also described.     

Spontaneous plant regeneration in transformed roots and calli from Tylophora indica: changes in morphological phenotype and tylophorine accumulation associated with transformation by Agrobacterium rhizogenes

We examined the effects of genetic transformation by Agrobacterium rhizogenes on the production of tylophorine, a phenanthroindolizidine alkaloid, in the Indian medicinal plant, Tylophora indica. Transformed roots induced by the bacterium grew in axenic culture and produced shoots or embryogenic calli in the absence of hormone treatments. However, hormonal treatment was required to regenerate shoots in root explants of wild type control plants. Transformed plants showed morphological features typically seen in transgenic plants produced by A. rhizogenes, which include, short internodes, small and wrinkled leaves, more branches and numerous plagiotropic roots. Plants regenerated from transformed roots showed increased biomass accumulation (350–510% in the roots and 200–320% in the whole plants) and augmented tylophorine content (20–60%) in the shoots, resulting in a 160–280% increase in tylophorine production in different clones grown in vitro.     

Overexpression of Arabidopsis phytochelatin synthase in tobacco plants enhances Cd2+ tolerance and accumulation but not translocation to the shoot

Phytochelatins (PCs) are metal binding peptides involved in heavy metal detoxification. To assess whether enhanced phytochelatin synthesis would increase heavy metal tolerance and accumulation in plants, we overexpressed the Arabidopsis phytochelatin synthase gene (AtPCS1) in the non-accumulator plant Nicotiana tabacum. Wild-type plants and plants harbouring the Agrobacterium rhizogenes rolB oncogene were transformed with a 35S AtPCS1 construct. Root cultures from rolB plants could be easily established and we demonstrated here that they represent a reliable system to study heavy metal tolerance. Cd²⁺ tolerance in cultured rolB roots was increased as a result of overexpression of AtPCS1, and further enhanced when reduced glutathione (GSH, the substrate of PCS1) was added to the culture medium. Accordingly, HPLC analysis showed that total PC production in PCS1-overexpressing rolB roots was higher than in rolB roots in the presence of GSH. Overexpression of AtPCS1 in whole seedlings led to a twofold increase in Cd²⁺ accumulation in the roots and shoots of both rolB and wild-type seedlings. Similarly, a significant increase in Cd²⁺ accumulation linked to a higher production of PCs in both roots and shoots was observed in adult plants. However, the percentage of Cd²⁺ translocated to the shoots of seedlings and adult overexpressing plants was unaffected. We conclude that the increase in Cd²⁺ tolerance and accumulation of PCS1 overexpressing plants is directly related to the availability of GSH, while overexpression of phytochelatin synthase does not enhance long distance root-to-shoot Cd²⁺ transport.     

Genetic evidence that induction of root Fe(III) chelate reductase activity is necessary for iron uptake under iron deficiency†

Reduction of Fe(III) to Fe(II) by Fe(III) chelate reductase is thought to be an obligatory step in iron uptake as well as the primary factor in making iron available for absorption by all plants except grasses. Fe(III) chelate reductase has also been suggested to play a more general role in the regulation of cation absorption. In order to experimentally address the importance of Fe(III) chelate reductase activity in the mineral nutrition of plants, three Arabidopsis thaliana mutants (frd1-1, frd1-2 and frd1-3), that do not show induction of Fe(III) chelate reductase activity under iron-deficient growth conditions, have been isolated and characterized. These mutants are still capable of acidifying the rhizosphere under iron-deficiency and accumulate more Zn and Mn in their shoots relative to wild-type plants regardless of iron status. frd1 mutants do not translocate radiolabeled iron to the shoots when roots are presented with a tightly chelated form of Fe(III). These results: (1) confirm that iron must be reduced before it can be transported, (2) show that Fe(III) reduction can be uncoupled from proton release, the other major iron-deficiency response, and (3) demonstrate that Fe(III) chelate reductase activity per se is not necessarily responsible for accumulation of cations previously observed in pea and tomato mutants with constitutively high levels of Fe(III) chelate reductase activity.     

Influence of Nitrogen Supply and Water Stress on Growth and Nitrogen, Phosphorus, Potassium and Calcium Contents in Pearl Millet

Influence of supra-optimal concentrations of N on growth and accumulation of N, K, P and Ca in the shoots and roots in Pennisetum glaucum (L.) R.Br. under water stress was assessed in a pot experiment under glasshouse conditions. Thirty four-day-old plants of two lines, ICMV94133 and WCA-78, were subjected to 224, 336, or 448 mg(N) kg^–1(soil) and soil moisture 100 or 30 % of field capacity for 30 d. Increasing soil N supply decreased growth of both lines under water deficit. Nitrogen content in the shoots of both lines was not affected by supra-optimal levels of N or different watering regimes, but in contrast, the root N content was increased consistently in WCA-78 with increase in soil N content. Shoot P content increased considerably in WCA-78 at the two higher N contents, but it was significantly lower at drought stress than at well-watered treatment. In contrast, shoot or root P content in ICMV94133 did not differ under both watering regimes. Potassium content in the shoots of WCA-78 was considerably increased at the two higher N contents under drought conditions. Root K content was increased in WCA-78 at the highest N content under well-watered conditions, whereas the reverse was true in ICMV94133. Calcium content in the shoots of ICMV94133 was higher under drought stress compared with that at well-watered conditions, but such pattern was not observed in WCA-78. However, root Ca content increased in both lines with increase in N supply.     

Effects of nitrogen and phosphorus deficiencies on levels of carbohydrates, respiratory enzymes and metabolites in seedlings of tobacco and their response to exogenous sucrose

A simple method of growing plants in agar was exploited to investigate the effect of long-term nitrogen (N) and phosphorus (P) deficiencies on respiratory metabolism and growth in shoots and roots of Nicotiana tabacum seedlings, and their interaction with exogenously supplied sucrose. Levels of hexose phosphates and 3-phosphoglyceric acid (3-PGA) were low in P-deficient shoots and roots and high in N-deficient shoots and roots. The ratio of hexose phosphates to 3-PGA and levels of fructose-2,6-bisphosphate were high in P-deficient plants and low in N-deficient plants. These data reflect differences in the way metabolism was perturbed, yet both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots. Enzymes for sucrose degradation (sucrose synthase, acid and alkaline invertase) and glycolysis (phosphofructokinase, pyrophosphate-dependent phospho-fructokinase and pyruvate kinase) remained unaltered or declined in the shoots and roots. The accumulation of hexoses in roots of N- and P-deficient plants may result from maintenance of high invertase activities relative to sucrose synthase and glycolytic enzymes in the roots. The possibility that hexose accumulation may drive preferential root growth osmotically in N and P deficiencies is discussed. The addition of sucrose to roots to further investigate the interaction of carbohydrates with growth and allocation in low N and low P produced clear effects even though endogenous levels of soluble carbohydrate were already high in the nutrient-deficient plants. In complete nutrition, growth was stimulated, protein content particularly of the roots was increased and there was a preferential increase in activity of sucrose synthase in roots. At low P, enzyme activities in roots were increased, including sucrose synthase, and protein content increased, particularly in the roots, but there was no increase in growth. In N-deficient plants, exogenous sucrose led to decreased protein, Rubisco and chlorophyll content in shoots, in contrast to the other conditions, and a higher protein content and a general increase of catabolic enzyme activities and growth in the roots.     

Fe2O3 nanoparticles induced biochemical responses and expression of genes involved in rosmarinic acid biosynthesis pathway in Moldavian balm under salinity stress

The effect of iron oxide nanoparticle (NP) at four concentrations (0, 30, 60 and 90 ppm) and salinity at three levels (0, 50 and 100 mM) were investigated on rosmarinic acid (RA) production in 5-week-old Moldavian balm (Dracocephalum moldavica L.) plants. Salinity and spraying iron oxide NPs significantly affected tyrosine (Tyr), phenylalanine (Phe) and proline (Pro) amino acids content, Phenylalanine Ammonia-Lyase (PAL), Tyrosine Aminotransferase (TAT) and Rosmarinic Acid Synthase (RAS) genes expression levels, RA content, Polyphenol Oxidase (PPO), PAL and Superoxide Dismutase (SOD) activities, malondialdehyde (MDA) content and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. PAL, TAT and RAS genes expression rate and content of RA were enhanced in Moldavian balm plants exposed by NaCl + NPs. The results of high performance liquid chromatography (HPLC) revealed that simultaneous application of 50 mM NaCl and 90 ppm NPs increases the RA content in leaf by 81.15% as compared to control plants. The Tyr and Phe contents decreased in Moldavian balm plants exposed to salt stress. Application of NPs had a positive effect on the content of these amino acids. Proline content increased under salinity stress and application of iron NPs induced a significant increase in the Pro content of leaf. The results revealed that PAL, PPO and SOD enzymes activities increased under salinity conditions. The highest activity of PPO and SOD was observed in 100 mM NaCl + 60 ppm NPs treatment. Simultaneous application of 100 mM NaCl + 90 ppm NPs increased the MDA content and DPPH radical scavenging activity compared to control plants. It can be concluded that the application of appropriate levels of NPs moderates the effect of salinity stress in D. moldavica L. and results in an increased amount of RA compared to control plants.