Grain filling pattern of Hordeum vulgare as affected by salicylic acid and salt stress

Although application of salicylic acid (SA) to various plants grown on saline soils has been examined adequately, the effect of SA on changes during grain filling period has not been studied in details. In this 2-year field study, the grain-filling pattern of barley has been monitored as affected by different SA concentrations (0, 0.5, 1.0, 1.5, and 2.0?mM) under varied irrigation salinity levels (2 and 12?dSm^?1) during 2012–2013 and 2013–2014 growing seasons. In both years, total soluble carbohydrates (TSC) increased up to 15?days after anthesis (DAA) and then decreased until the end of the grain-filling period. However, starch content (SC) and the mean grain weight (MGW) increased form the first sampling, and such increase was substantial between 15 and 25 DAA. The grain growth rate (GGR) and the absolute grain growth rate (AGGR) were enhanced up to 20 DAA and then were reduced until 30 DAA. The grain-filling pattern changed by salt stress, so that TSC was greater for the salt stressed plants from 15 or 10 DAA in the first and the second years, respectively. Throughout the grain-filling period, SC, MGW, and AGGR were lower under saline conditions in both years. Application of SA increased TSC, SC, MGW, GGR, and AGGR from 15 to 20 DAA, however, the effect of SA was obvious earlier under saline than the non-saline conditions. Generally, it can be concluded that SA foliar application might increase grain weight through modulating the negative impact of salt stress on carbohydrate and starch contents. It also appeared that the effect of SA was obvious earlier under salt stress conditions.     

Barley growth,yield, antioxidant enzymes,and ion accumulation affected by PGRs under salinity stress conditions

Application of plant growth regulator (PGR) may alleviate some negative effects of environmental stresses such as salinity. A controlled environment experiment was conducted to study barley (Hordeum vulgare L. cv. Reyhane) growth, yield, antioxidant enzymes and ions accumulation affected by PGRs under salinity stress conditions at Shiraz University during 2012. The treatments were PGRs at four levels—water (as control), cycocel (CCC, 19 mM), salicylic acid (SA, 1 mM), and jasmonic acid (JA, 0.5 mM)—and four salinity levels—no stress (0.67 dS m^?1, as control), 5, 10, and 15 dS m^?1, which were arranged in a factorial experiment based on completely randomized design with four replicates. The results showed that salinity stress significantly decreased plant height, peduncle length, leaf area, ear length, grain number, dry weight, grain yield, harvest index, potassium (K⁺) accumulation, and potassium/sodium (K⁺/Na⁺) concentration ratio, which were closely associated with stress severity. However, PGRs compensated some of these negative effects, so that SA foliar application had the most ameliorative effect. Salt stress also increased Na⁺ accumulation as well as the activity of peroxidase, catalase, and superoxide dismutase (SOD). Since ion discrimination and enhanced antioxidant enzymes are associated with salt tolerance, in this experiment PGRs application might have enhanced K⁺ accumulation and antioxidant enzyme activity. The activity of SOD and K⁺/Na⁺ ratio were found to be useful in salt tolerance manipulation in barley plants.     

Silicon-induced changes in growth,ionic composition,water relations,chlorophyll contents and membrane permeability in two salt-stressed wheat genotypes

We investigated the effect of exogenously applied silicon (Si) on the growth and physiological attributes of wheat grown under sodium chloride salinity stress in two independent experiments. In the first experiment, two wheat genotypes SARC-3 (salt tolerant) and Auqab 2000 (salt sensitive) were grown in nutrient solution containing 0 and 100 mM sodium chloride supplemented with 2 mM Si or not. Salinity stress substantially reduced shoot and root dry matter in both genotypes; nonetheless, reduction in shoot dry weight was (2.6-fold) lower in SARC-3 than in Auqab 2000 (5-fold). Application of Si increased shoot and root dry weight and plant water contents in both normal and saline conditions. Shoot Na⁺ and Na⁺:K⁺ ratio also decreased with Si application under stress conditions. In the second experiment, both genotypes were grown in normal nutrient solution with and without 2 mM Si. After 12 days, seedlings were transferred to 1-l plastic pots and 150 mM sodium chloride salinity stress was imposed for 10 days to all pots. Shoot growth, chlorophyll content and membrane permeability were improved by Si application. Improved growth of salt-stressed wheat by Si application was mainly attributed to improved plant water contents in shoots, chlorophyll content, decreased Na⁺ and increased K⁺ concentrations in shoots as well as maintained membrane permeability.     

The role of potassium and zinc in reducing salinity and alkalinity stress conditions in two wheat genotypes

Soil salinity may reduce potassium (K) uptake due to strong competition with sodium cations at the root surface. In calcareous soils, zinc (Zn) precipitates in forms unavailable to plants. This study evaluated the responses of two wheat genotypes (C), Baccrosroshan and salinity-tolerant Line No. 4, to K and Zn fertilizers in both greenhouse and farm experiments with similar soil and water conditions. A factorial experiment with four K levels (K0 = 0, K1 = 72, K2 = 144 and K3 = 216 kg K₂O ha^?1) and three Zn levels (Zn0 = 0, Zn1 = 20 and Zn2 = 40 kg ha^?1) based on a randomized complete block design was employed. Analysis of variance results showed significant Zn × K × C interactions on all measured traits. Despite sufficient available potassium and illite clay in the root-growing medium, plants responded to K application. Yield components, grain yield and protein content of the two genotypes increased linearly as Zn × K increased. Considering Zn2K2 and Zn2K3, Line No. 4 produced 17% higher 1000-grain weight, 30% higher weight of grains per ear and 23% higher grain yield than Baccrosroshan in the farm experiment, and 10, 50, 16% higher values, respectively, in the greenhouse experiment. Results showed a significant relationship between grain weight per ear and grain yield. The achieved results highlight the importance of K and Zn nutrition under salt-stress conditions.     

Assessment of salinity tolerance threshold for two wheat genotypes in response to zinc

Plants’ tolerance to salt stress is different among species, nevertheless, mineral nutrition might also affect it. A greenhouse experiment was conducted to evaluate the effect of Zinc (Zn) on salinity tolerance using a sigmoid response model in two wheat (Triticum aestivum L.) genotypes ‘Falat’ and ‘Bam’ with different salinity tolerances. The treatments consisted of three Zn rates (0, 5 and 10 mg Zn kg^?1) and five levels of soil salinity (1.1, 6.5, 12.3, 18.7 and 25.1 dS m^?1). The results showed that dry weight of straw and grain decreased, as salinity increased in both genotypes although this decrease in ‘Falat’ genotype was higher than that of ‘Bam’ genotype. Application of 10 mg kg^?1 Zn increased the dry weight by 25% (straw) and 32% (grain) in ‘Falat’ but 67% (straw) and 60% (grain) in ‘Bam’ as compared with the absence of added Zn. According to the fitted function, in the absence of Zn, grain production began to decline at EC_e-values of 4.7 dS m^?1 in ‘Falat’ genotype, and 7.5 dS m^?1 in ‘Bam’ genotype. Application of Zn led to a decrease of salinity tolerance in ‘Falat’ genotype, but an increase in ‘Bam’ genotype. The study found that Zn application under saline conditions, depending on genetic differences of wheat genotypes, would have different effects on their tolerance to salinity.     

Seed priming and soil incorporation with silicon influence growth and yield of maize under water-deficit stress

Silicon (Si) has been known to enhance plant tolerance against biotic and abiotic stresses besides its beneficial effects on plant growth and yield. Two experiments were conducted to evaluate the effect of Si against water-deficit stress in maize (Zea mays) applied through seed priming and soil incorporation methods, and to find out the optimum dose of Si under each method. In the seed priming experiment, seeds were exposed to different Si levels, up to 2 mM l^–1, germinating under three soil moisture regimes (100%, 75% and 50% field capacity-FC). In the soil incorporation study, the treatments included were six Si doses from 0 to 600 kg ha^–1 under the same soil moisture regimes. Grain yield was reduced by 59% and 69% in the seed priming and soil incorporation study, respectively, at 50% FC. Si application was effective irrespective of the application methods with higher cob length, 100-kernel weight and grain yield than the control. Application of Si at 1 mM l^–1 as seed priming and 300 kg ha^–1 as soil incorporation was more effective than other doses and could be recommended as optimum dose for Nakhon Sawan 3 hybrid maize variety under water-deficit stress.     

Silicon-Induced Growth and Yield Enhancement in Two Wheat Genotypes Differing in Salinity Tolerance

Silicon (Si) is known to alleviate a number of abiotic stresses in higher plants including salinity stress. Two independent experiments were conducted to evaluate the role of Si in alleviating salinity stress in two contrasting wheat (Triticum aestivum L.) genotypes, Auqab-2000' (salt sensitive) and SARC-3 (salt tolerant). In the first experiment, genotypes were grown in hydroponics with two levels of salinity (0 and 60 mM NaCl) with and without 2 mM Si in a completely randomized design with four replications. Salinity stress significantly (P < 0.01) decreased all of the growth parameters, increased sodium (Na⁺) concentration, and decreased potassium (K⁺) concentration in shoots of both genotypes grown in hydroponics. Silicon significantly improved growth of both genotypes. The increase in growth was more prominent under salt stress (75%) than under normal condition (15%). In the second experiment, both genotypes were grown in normal [electrical conductivity (EC) = 1.23 d Sm^–1] and natural saline field (EC = 11.92 d Sm^–1) conditions with three levels of Si (0, 75, and 150 g g^–1 Si) with three replications in a randomized complete block design. Silicon significantly (P < 0.05) decreased growth reduction in both genotypes caused by salinity stress. The grain yield under salt stress decreased from 62% to 33% and from 44% to 20% of the maximum potential in Auqab-2000 and SARC-3, respectively, when 150 g g^–1 Si was used. Auqab-2000 performed better in normal field conditions, but SARC-3 produced more straw and grain yield in saline field conditions. Addition of Si significantly (P < 0.05) improved K uptake and reduced Na⁺ uptake in both of wheat genotypes and increased the K⁺/Na⁺ ratio in shoot. Enhanced salinity tolerance and improved growth in wheat by Si application was attributed to decreased Na⁺ uptake, its restricted translocation toward shoots, and enhanced K⁺ uptake.     

Salicylic Acid–Induced Salinity Redressal in Hydroponically Grown Strawberry

The present study was conducted to evaluate shoot and root mineral composition of salt-stressed Selva strawberry under application timing of salicylic acid (SA). Treatments included plants sprayed with 0.5 or 1 mM SA, plants exposed to 40 mM sodium chloride (NaCl), and plants sprayed with 0.5 or 1 mM SA 1 week before, simultaneously, or after initiation of 40 mM salinity. Results indicated that under saline conditions, sodium (Na) and chloride (Cl) contents increased along with decrease in nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and zinc (Zn) in shoot and root of plants. In plants treated with SA at 1 mM concentration, 1 week before salinity application, root Mg and shoot Ca were greater in comparison to salt-stressed plants treated with the same SA concentration 1 week after their exposure to salt stress. Thus, earlier SA application appears to be a better strategy for optimized protection against deleterious influence of salinity.     

Phosphorous and beneficial microorganism influence yield and yield components of wheat under full and limited irrigated conditions

Field experiment was conducted to investigate the impact of phosphorus (P) and beneficial microorganism (BM) on the yield and yield components wheat (Triticum aestivum L., cv. Siren-2010). The experiment was conducted under full (five irrigations) and limited (two) irrigation conditions at the Research Farm of The University of Agriculture Peshawar during winter 2012–13. The experiment under both full and limited irrigated conditions was laid out in randomized complete block design using three replications. The results showed that irrigated plots produced more spikes m^?2 (254), grains spike^?1 (55.5), heavier thousand grains weight (39.4 g), and higher grain yield (3612 kg ha^?1 than limited irrigated condition. Application of P at the highest rate (90 kg P ha^?1) produced more spikes m^?2 (260) and grains spike^?1 (52.4), and increased maximum thousand grain weight (39.1 g) and grain yield (3617 kg ha^?1). Application of BM at the highest rate (30 L ha^?1) resulted in maximum number of spikes m^?2 (257) and grains spike^?1(51.7), highest thousand grains weight (39.1 g) and grain yield (3765 kg ha^?1). The results confirmed that under full irrigated condition the increase in both P and BM levels (90 kg P ha^?1 and 30 L ha^?1, respectively) and under limited irrigated condition the intermediate levels of both P and BM (60 kg P ha^?1 and 20 L ha^?1, respectively) could increase wheat productivity under semi-arid conditions.     

Interactive effects of salinity and two phosphorus fertilizers on growth and grain yield of Cicer arietinum L.

Chickpea is considered among the most sensitive grain legumes to salinity. The improvement of tolerance of lines in combination with tolerant rhizobial strains depends on various environmental and cultural conditions such as soil properties. This investigation was undertaken to evaluate the effect of phosphorus fertilization (0, 90 and 200 kg ha^?1 of P₂O₅) on biomass, nodular traits and grain yield (GY) of chickpea (cv. Flip 84-79C) growing under salinity (0 and 150 mM NaCl). The trial was laid out following a randomized block design with three replicates during 2010–2012, at the experimental farm of Oued Smar (Algiers). Salinity did not significantly decrease the dry biomass of the plants but the relative shoot growth was more affected than control, P and SP1 treatments. Besides, salinity significantly reduced GY (?20%) and nodulation traits compared to the control plants while an inversely proportional relationship was found between protein, leghemoglobin and MDA content, K/Na ratio and the increase in salt concentration. Application of two P levels to saline soil enhanced growing conditions of plants. Particularly, the (90?kg?ha^–1 of P ×?150?mM?NaCl) combination significantly increased leghemoglobin (92%), reduced proline content (?69%) and protected membranes against peroxydation compared to saline conditions. A significant increase was observed in the GY (about 30%) of plants at both P doses combined with salt stress compared to other cases. Statistically, the low P level combined with salinity induced similar responses of plants and sometimes better responses to control plants. Finally, our results support the roles of phosphorus fertilizer in the alleviation of salt stress and enhancing the soil quality for better symbiosis efficiency and yield of chickpea.     

Interactive effects of Si and NaCl on growth,yield, photosynthesis,and ions content in strawberry (Fragaria × ananassa var Camarosa)

The effects of silicon (Si) (0, 1, and 2 mM) and sodium chloride (NaCl) salinity (0, 20, and 40 mM) on the yield, photosynthesis, and ion content in strawberry grown in hydroponics were investigated. Salinity caused a reduction in leaf area and plant biomass, regardless of Si supplement. Leaf area in Si₁Na₂₀ treatment was 37% higher than that of Si₀Na₂₀ treatment. Salinity at 20 mM concentration had a 25% yield reduction in absence of Si, corresponding to no reduction in the yield in the presence of Si compared with the Si treatment without salinity. The highest reduction of photosynthetic rate (Pn) was observed in Si₁Na₄₀ treatment; however, in the presence of Si, there was no reduction in the Pn rate at 20 mM NaCl concentration. An obvious positive relationship was found between potassium/sodium (K/Na) and Pn rate. Within each Si concentration, the increased salinity increased Na concentration in the leaf tissue. However, when Si was supplied to the salinity treatments Na concentration was significantly lower than that of the similar treatments without Si. Supplement of Si to the nutrient solution increased the Si concentration in the roots, and old and young leaves. A clear negative relationship (r² = 0.71) was found between Si and Na concentration in the leaves. Salinity (NaCl₄₀) increased the proline level 2.5-fold in the absence of Si, corresponding to no changes the proline level in the presence of 1 mM Si concentration compared with the Si treatment without salinity. The salinity (40 mM) increased the electroleakage by 50% compared with 0 mM NaCl treatment in the absence of Si supplement. Findings from this study lead to the conclusion that Si supplement to the nutrient solution ameliorated the deleterious effect of salinity on the strawberry growth; these effects were attributed to an enhanced K/Na ratio and the reduction in Na content and electroleakage ability in the leaf tissue.     

Effectiveness of salicylic acid in mitigating salt-induced adverse effects on different physio-biochemical attributes in sweet basil (Ocimum basilicum L.)

The objective of this study was to determine the effects of foliar salicylic acid (SA) on salt tolerance of sweet basil seedlings by examining growth, photosynthetic activity, total osmoregulators, and mineral content under salinity. Salinity treatments were established by adding 0, 60, and 120 mM sodium chloride (NaCl) to a base nutrient solution. The addition of 60 and 120 mM NaCl inhibited the growth, photosynthetic activity, and nutrient uptake of sweet basil seedlings, and increased the electrolyte leakage and the plant contents of proline and Na. Sweet basil seedlings were treated with foliar SA application at different concentrations (0.0, 0.50, and 1.00 mM). Foliar applications of SA led to an increase in the growth, chlorophyll content, and gas exchange attributes. With regard to nutrient content, it can be inferred that foliar SA applications increased almost all nutrient content in leaves of sweet basil plants under salt stress. Generally, the greatest values were obtained from 1.00 mM SA application.     

Investigation of soil compaction on yield and agronomic traits of wheat under saline and non-saline soils

Inappropriate crop management and long-term use of heavy agricultural equipment can lead to soil compaction. On the other hand, soil and water salinity causes reduction in the plant yield in addition to adverse effects on plants tolerance to the various stresses. The aim of this study was to investigate the interaction between soil compaction and salinity on the macronutrients uptake and wheat yield as well as its agronomic traits. The pot experiment was carried out on the loamy soil in a completely randomized block design with three replications. The treatments consisted of two salinity types (saline, EC = 6 dS/m and non-saline soil) and five levels of compaction; control, 5%, 10%, 15% and 20%. The results showed that soil compaction had significant effect on the amount of N, P and K in wheat grain, so that the uptake of N, P and K by grain has been decreased by increasing the compaction level of soil. Soil salinity had significant effect on N, P and K content in grain that the content of N, P and K has been diminished in the saline treatments compared to non-saline treatments. Results on the agronomic traits and yield of wheat also revealed that soil compaction and salinity had significant effect (p < 0.01) on straw weight, number of ears, number of grain, and thousand grain weight which caused reduction in these parameters. The interaction between compaction and salinity had only significant correlation (p < 0.01) with thousand grain weight leading to the decrement of thousand grain weight with increasing compaction levels, particularly in the saline treatment.     

Effect of exogenous application of salicylic acid on salt-stressed sorghum growth and nutrient contents

This study was conducted to investigate the effect of salinity and foliar application of salicylic acid (SA) on sorghum biomass and nutrient contents. Treatments were comprised of salinity levels (0 and 100?mM NaCl) and SA concentrations (0.3, 0.7, 1.1 and 1.5?mM). Salinity increased sodium (Na), chlorine (Cl) and copper (Cu) but decreased nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), sulfur (S), iron (Fe), zinc (Zn) and manganese (Mn) contents and the root and shoot dry matter. Fe and Zn were the most affected nutrients by salinity. However, SA reduced Na and Cl but increased plant dry matter and nutrient content. SA had greater positive effects on root than on shoot dry matter. Maximum increases through SA were achieved in N, K, Fe, Mn, Cu, and shoot weight under salt stress but in Zn and root weight under non-saline condition. In most cases 1.1?mM was the most effective SA concentration in reducing the negative effects of salinity.     

Efficiency of Potassium Fertilization and Salicylic Acid on Yield and Nutrient Accumulation of Sugar Beet Grown on Saline Soil

Rising soil salinity has been a major problem in the soils of Egypt in recent decades. Potassium fertilization and salicylic acid (SA) play an important role in promoting plants to tolerate salt stress and increased the yield of sugar beet crop. A field experiment on sugar beet (Beta vulgaris L.) grown on saline soil was carried out during 2014 growing season in Port Said Governorate, Egypt, to study the effect of potassium fertilization of the soil at applications of 0, 100, 150, and 200 kg potassium (K) ha^?1 and foliar spray of SA by solution of 1000 mg L^?1, twice (1200 L ha^?1 each time) on yield and nutrient uptake. Application of 200 kg K ha^?1 in combination with salicylic foliar spray gave the highest root length, root diameter, shoot and root yield, sucrose, juice purity percentage, gross sugar yield, and white possible extractable sugar, nitrogen (N), phosphorus (P), and potassium (K) content, and uptake of sugar beet. The highest increase in sucrose (20%) as well as white possible extractable sugar (184%) was obtained by 200 kg K ha^?1 in combination with salicylic foliar spray compared with untreated soil with potassium fertilization and without salicylic foliar spray.     

Shift in physiological and biochemical processes in wheat supplied with zinc and potassium under saline condition

Soil salinity is a serious abiotic factor affecting the production of crops by reducing potassium (K) uptake due to strong competition with sodium (Na) cations in the root regions. In calcareous soils, most of the nutrients precipitate in unavailable forms for plants. This study investigated the physiological and biochemical response of two wheat genotypes salt tolerant Abadghar and salt sensitive Pari-73 supplemented with K and zinc (Zn) nutrition. A factorial experiment with three levels of K (0, 50 and 100 kg ha^?1) and three levels of Zn (0, 25 and 50 kg ha^?1) based on a complete randomized design was employed. The results showed significant effect of treatments on chlorophyll (Chl) contents, water relations, nitrogen metabolism and yield attributes. The treatment K+Zn (100, 25 kg ha^?1) was the most effective in increasing grain yield. The results achieved highlight the importance of K and Zn nutrition in salt-stress conditions.     

Response of Wheat Plants to Zinc,Iron, and Manganese Applications and Uptake and Concentration of Zinc,Iron, and Manganese in Wheat Grains

This experiment was conducted at Zahak Agricultural Research Station in the Sistan region in southeast Iran. A factorial design with three replications was used to determine the effects of zinc (Zn), iron (Fe), and manganese (Mn) applications on wheat yield, Zn, Fe, and Mn uptakes and concentrations in grains. Four levels of Zn [soil applications of 0, 40, and 80 kg ha^?1 and foliar application of 0.5% zinc sulfate (ZnSO₄) solution], two levels of iron sulfate (FeSO₄; 0 and 1%) as foliar application, and two levels of Mn (0 and 0.5%) also as foliar application were used in this study. Results showed that the interactive effects of Zn and Mn were significant on the number of grains in each spike. The highest number of grains resulted from the application of 80 kg ZnSO₄ ha^?1 and foliar Mn. The interactive effects of Zn and Fe were significant on weight of 1000 grains. The highest weight of 1000 grains resulted from application of 80 kg Zn and foliar Fe. Application of 80 kg ZnSO₄ ha^?1 alone and 80 kg ZnSO₄ ha^?1 with foliar application of Mn significantly increased grain yield in 2003. The 2‐year results showed that foliar application of Zn increased Zn concentration and Fe concentration in grains 99% and 8%, respectively. Foliar application of Fe resulted in a 21% increase in Fe concentration and a 13% increase in Zn concentration in grains. The foliar application of Mn resulted in a 7% increased in Mn concentration in grains.     

Effect of Foliar Salicylic Acid Applications on Growth,Chlorophyll, and Mineral Content of Cucumber Grown Under Salt Stress

The objective of this study was to determine the effect of foliar salicylic acid (SA) applications on growth, chlorophyll, and mineral content of cucumber grown under salt stress. The study was conducted in pot experiments under greenhouse conditions. Cucumber seedlings were treated with foliar SA applications at different concentrations (0.0, 0.25, 0.50, and 1.00 mM). Salinity treatments were established by adding 0, 60, and 120 mM of sodium chloride (NaCl) to a base complete nutrient solution. The SA was applied with spraying two times as before and after transplanting. Salt stress negatively affected the growth, chlorophyll content and mineral uptake of cucumber plants. However, foliar applications of SA resulted in greater shoot fresh weight, shoot dry weight, root fresh weight, and root dry weight as well as higher plants under salt stress. Shoot diameter and leaf number per plant increased with SA treatments under salt stress. The greatest chlorophyll content was obtained with 1.00 mM SA treatment in both saline and non-saline conditions. Leaf water relative content (LWRC) reduced in response to salt stress while SA raised LWRC of salt stressed cucumber plants. Salinity treatments induced significant increases in electrolyte leakage. Plants treated with foliar SA had lower values of electrolyte leakage than non-treated ones. In regard to nutrient content, it can be interfered that foliar SA applications increased almost all nutrient content in leaves and roots of cucumber plants under salt stress. Generally, the greatest values were obtained from 1.00 mM SA application. Based on these findings, the SA treatments may help alleviate the negative effect of salinity on the growth of cucumber.     

稻田土壤铜含量对水稻籽粒灌浆特性与产量的影响

为探究稻田土壤铜含量对水稻产量及籽粒灌浆特性的影响,于2019和2021年通过盆栽试验分析24.32(对照,CK)、100(Cu100)和200 mg·kg^-1(Cu200)稻田土壤铜含量下水稻的产量差异,并通过Richards方程对籽粒灌浆过程进行拟合,比较籽粒灌浆参数之间的差异,探讨铜含量对不同粒位籽粒灌浆特性的影响。结果表明,2019和2021年Cu200处理水稻产量较CK分别减少31.18%和39.50%(P<0.05);而Cu100处理水稻产量较CK分别表现为减少12.94%(P<0.05)和增加10.07%(P>0.05)。土壤不同铜含量处理下水稻籽粒灌浆特性表明,与对照相比,Cu100处理强势粒延长了活跃灌浆期(D)和到达最大灌浆速率的时间(T_max),最终生长量A值提高,而弱势粒D值及T_max明显缩短,A值明显降低;Cu200处理强、弱势粒D值及T_max明显减小,A值显著降低。总体而言,各处理对弱势粒灌浆影响大于强势粒。进一步分析不同土壤铜含量下水稻产量变化规律发现...     

Silicon modulates the activity of antioxidant enzymes and nitrogen compounds in sunflower plants under salt stress

Sunflower (Helianthus annuus L.) is an important oilseed crop with clear sensibility to salt stress. In this study, we evaluated silicon (Si) effect on the nitrogen metabolism and antioxidant enzyme activity in sunflower plants subjected to salinity. A 4 × 4 factorial arrangement of treatments in a completely randomized design with four replicates was used, consisting of four concentrations of Si (0.0; 1.0; 1.5; and 2.0 mM) and four concentrations of NaCl (0; 50; 100; and 150 mM) in the nutrient solution. The salinity reduced the nitrate content, but the increasing Si concentration in the medium improved the nitrate uptake, leading this ion to accumulate in salt-stressed plants, particularly in the roots. The nitrate reductase activity and the proline and soluble N-amino contents were also significantly increased by Si in salt conditions. The salinity increased electrolyte leakage and reduced the activity of enzymes superoxide dismutase, ascorbate peroxidase and catalase in sunflower plants, but these decreases were reversed by Si at 2 mM, thus alleviating the effects of salinity on these variables. We conclude that Si is able to positively modulate nitrogen metabolism and antioxidant enzyme activities in sunflower plants in order to alleviate the harmful effects of salinity.