Exploring the genetic basis of pre-harvest sprouting in rice through a genome-wide association study-based haplotype analysis

Pre-harvest sprouting(PHS)poses a significant global challenge to cereal production,impacting both yield and quality.In this study,we employed genome-wide association studies(GWAS)on diverse rice accessions to identify novel PHS-associated haplotypes.An assessment of 127 cultivated accessions for panicle germination(PHS)and detached grain germination(germination rate of detached grains at the 14th day(D14))revealed considerable phenotypic variation among rice ecotypes.GWAS analysis identified 91 significant signals at–log10(P-value)>5,including 15SNPs for PHS and 76 SNPs for D14.A subsequent linkage disequilibrium(LD)block-based GWAS analysis detected 227 significant SNPs for both traits,consisting of 18 nonsynonymous substitutions located on the coding regions of nine genes.Further haplotype analysis identified 32 haplotypes,with 10 specific to cultivated accessions,19 specific to the wild type,and three shared between them.A phenotypic assessment of major haplotypes revealed significant differences between resistant(Hap1 and Hap2)and susceptible haplotypes(Hap5,Hap27,and Hap28),distinguished by a G/A SNP within a novel gene,Os04g0545200.The identified haplotypes offer promising prospects for haplotypebased breeding aimed at enhancing PHS resistance in rice.

Arginine promotes seed energy metabolism,increasing wheat seed germination at low temperature

Low temperatures during germination inhibit seed growth,lead to small and weak seedlings,and significantly reduce the wheat yield.Alleviating the adverse effects of low temperature on wheat seed germination is highly important for achieving high and stable wheat yields.In this study,Tongmai 6(insensitive)and Zhengmai 113(sensitive),which have different low-temperature sensitivities during germination were treated with low temperature during germination.The transcriptome,metabolome and physiological data revealed that low temperature decreased the germination rate,downregulated the expression of a large number of genes involved in regulating glycometabolism,and inhibited carbon,nitrogen(especially amino acids)and energy metabolism in the seeds.Arginine content increased at low temperature,and its increase in the low-temperature-tolerant variety was significantly greater than that in the sensitive variety.Arginine priming experiment showed that treatment with an appropriate concentration of arginine improved the seed germination rate.The conversion of starch to soluble sugar significantly increased under exogenous arginine conditions,the content of key metabolites in energy metabolism increased,and the utilization of ATP in the seeds increased.Taken together,arginine priming increased seed germination at low temperature by relieving inhibition of seed carbon and nitrogen metabolism and improving seed energy metabolism.

Genome-wide association study reveals that JASMONATE ZIM-DOMAIN 5 regulates seed germination in rice

Seed germination is a complex trait regulated by multiple genes in rice.However,the regulators of rice seed germination have yet to be sufficiently determined.Here,a quantitative trait locus(QTL)for rice seed germination was identified in a genome-wide association study.The candidate gene JASMONATE ZIM-DOMAIN 5(OsJAZ5)of the QTL was verified that positively regulates seed germination.OsJAZ5 regulation of seed germination involves an OsABI3-mediated abscisic acid pathway.Overexpression of OsJAZ5 facilitated seed germination.The application of OsJAZ5 might be useful for increasing seed germination for rice direct seeding.

OsbZIP01 Affects Plant Growth and Development by Regulating OsSD1 in Rice

As the‘Green Revolution’gene,SD1(encoding GA20ox2),has been widely applied to improve yield in rice breeding.However,research on its transcriptional regulation is limited.Here,we identified a transcription factor OsbZIP01,which can suppress the expression of SD1 and regulate gibberellin(GA)biosynthesis in rice.Knockout mutants of OsbZIP01 exhibited increased plant height,while the overexpression lines showed a semi-dwarf phenotype and diminished germination rate.Furthermore,the semi-dwarf phenotype of OE-bZIP01,was caused by the reduced internode length,which was accompanied by a thin stem width.The predominant expression of OsbZIP01 was observed in leaves and sheaths.OsbZIP01 protein was localized in the nucleus and showed transcriptional repression activity.In addition,OsbZIP01 could directly bind to the promoter of the OsSD1 gene,and inhibit its transcription.The semi-dwarf phenotype of OE-bZIP01 could be rescued by exogenous GA_(3).Meanwhile,the bzip01 sd1 double mutant showed a shorter shoot length compared with the wild type,indicating that OsbZIP01 regulated plant growth mainly through the GA biosynthesis pathway.Collectively,OsbZIP01 negatively regulates GA biosynthesis by restraining SD1 transcription,thereby affecting plant growth and development.

Relationship between Seed Priming Mediated Seedling Vigor and Yield Performance of Spring Wheat

Seed priming is a pre-germinated technique that can enhance seed germination percentage,faster and synchro-nized germination,better seedling growth,and yield under stress conditions.To ascertain the most effective seed priming method that would ensure the potential yield of wheat in Bangladesh,two experiments were carried out from December 2021 to March 2022 at the Department of Agronomy,Bangladesh Agricultural University.Two wheat varieties namely BARI Gom-28 and BWMRI Gom-1 were subjected to a range of priming chemicals in both lab and pot tests.These compounds included the following:control(no priming),hydropriming(distilled water),10000 ppm KNO_(3),15000 ppm KNO_(3),40000 ppm Mannitol,60000 ppm Mannitol,10000 ppm NaCl,20000 ppm NaCl,100 ppm PEG,150 ppm PEG,500 ppm NaOCl,1000 ppm NaOCl,10000 ppm CaCl_(2),20000 ppm CaCl_(2),10000 ppm KCl and 20000 ppm KCl.A complete randomized design(CRD)with three repli-cations was used to set up the experiments.The results showed that BARI Gom-28 and BWMRI Gom-1 responded best to KCl priming in terms of rapid seed germination and strong seedling development.On the other hand,the best priming agents for plant growth and productivity turned out to be CaCl_(2) and KCL.The results of this study support the possibility of using seed priming as a technique to improve wheat plant development and output by raising seed emergence and survival rates.

Effect of biochar on the metabolome of soybean seedlings

The use of biochar can have several effects on plant germination,depending on raw material,preparation method and application dose.However,the molecular mechanisms that lead to those results have yet to be elucidated.The aim of this research was to improve the understanding of these mechanisms by characterizing the metabolic effects of sugarcane bagasse biochar on soybean germination.Three types of biochars were prepared by pyrolysis at 300℃(SCB300),400℃(SCB400)and 600℃(SCB600).Then,each one was mixed into sand at 1%,3%,5%(w/w)dose,respectively.The experiment was performed in 8 days of incubation,when the number of germinated seeds and the average radicle length were determined.To evaluate the metabolome,the dry biomass(DB)was subjected to extraction with a mixture of methanol-d4 and D2O(1:1 v/v).The extracts were submitted to metabolomics analysis by Proton Nuclear Magnetic Resonance.The Relative Germination,Relative Average Radicle Growth and Germination Index increased in all treatments compared to control.On the other hand,the DB increased in all treatments,except for SCB300,at doses of 1%and 3%w/w.Seven metabolites(alanine,asparagine,acetic acid,citric acid,glycerol,fatty acids and sucrose)were identified and quantified in DB extracts as the most influential finding for the separation of treatments.Taken together,these results strongly suggested that biochars accelerated the catabolism of triacylglycerols to sucrose and induced a slight osmotic stress.

Preparation of Tartary Buckwheat Seed Coating Agent and Its Effect on Germination

To mitigate the wastage of seed resources and reduce the usage of pesticides and fertilizers, seed coating agentshave gained popularity. This study employs single-factor and multi-index orthogonal experimental design methodsto investigate the seed coating formula and physical properties of Tartary buckwheat. The specific effects ofeach component on Tartary buckwheat seed germination are analyzed. The findings reveal that the seed coatingagent formulated with 1.5% polyvinyl alcohol, 0.15% sodium alginate, 0.2% op-10, 0.1% polyacrylamide, 8% colorant,3% ammonium sulfate, 1% potassium dihydrogen phosphate, and 0.15% carbendazim exhibits the mosteffective coating. It demonstrates optimal physical properties and promotes seed germination efficiently. The suspensionrate of this seed coating agent reaches 91.12%, with a mere 2.13% coating shedding rate and 2.5% coatingseed rot rate. Furthermore, it achieves a germination percentage of 99.17%, which is 20.84% higher than the lowestgroup. The germination potential and index are also significantly higher than the lowest group, with anincrease of 20.84% and 26.56%, respectively. Additionally, the vitality index is 553.08, a 15.75% increase comparedto the lowest group. The application of seed coating agents helps reduce seed resource loss, increase plant numbers,and ultimately enhance agricultural yields. This finding holds practical significance in agriculturalproduction.

Effects of Low Temperature Stress on Germination and Physiological Characteristics of Different Sweet Maize Varieties

[Objectives]The paper was to explore the effects of low temperature stress on germination and physiological characteristics of different sweet maize varieties.[Methods]Taking Taitian 264,Zhexuetian 1 and Chaotian 4 as the research objects,the changes in germination potential,germination index,plant height,biomass,and antioxidant enzyme activity of maize seeds were studied under optimal temperature conditions(25℃)and low temperature stress conditions(10℃).[Results]Under 10℃stress,the germination rate and germination index of Taitian 264 were higher than that of Zhexuetian 1 and Chaotian 4.Under low temperature stress,Taitian 264 exhibited the least reduction in height and biomass,while Zhexuetian 1 had the most reduction.Additionally,the SOD and POD activities of Taitian 264 were higher than that of Zhexuetian 1 and Chaotian 4 under both temperature conditions,while the MDA content of Taitian 264 was lower.Taitian 264 showed strong germination ability against low temperature stress.[Conclusions]This study provides a basis for timely sowing practices of sweet maize in agricultural production.

The Toxic Effects of Strong Chlorin Disinfectant on Mangroves and Emission Thresholds

In this study, based on the simulated discharge results of chemical disinfectants, hypocotyl germination concentration gradient pre-test and concentration gradient determination experiment were set up respectively. Laboratory cultivation was conducted to compare and analyze the root germination and germination indexes, three mangrove hypocotyls of Kandelia candel (Linn.) Druce, Ceriopstagal C.B. Rob. and Bruguiera sexangula var. Rhynchopetalas’ efficiency of cumulative root germination, cumulative germination and the cumulative expansion of the second pair of leaves, one-way analysis of variance was used to obtain the tolerance threshold of three mangrove hypocotyls to strong chlorin disinfectant. The study determined that the by-products of strong chlorin disinfectant, the toxic threshold concentrations of Kandelia candel (Linn.) Druce, Ceriopstagal C.B. Rob. and Bruguiera sexangula var. rhynchopetala are close to 0.55 mg/L, 0.55 mg/L and 0.25 mg/L, respectively. This concentration range is lower than the average concentration of 1.183 mg/L of active chlorine emitted from strong chlorine concentrate during pond clearing in high-level shrimp ponds, indicating that transient emissions of strong chlorine concentrate during pond clearing can have a toxic effect on mangrove plants. The strength of tolerance of the embryonic axes of the three mangrove species to effective chlorine contamination was, Ceriopstagal C.B. Rob. stronger than Bruguiera sexangula var. rhynchopetala, and Kandelia candel (Linn.) Druce is the weakest.

Effect of Forest Litter on the Regeneration of Larix sibirica: Insight from Aqueous Extract and Litter Coverage

The effect of litter on forest regeneration depends on the characteristics of regional climate and also shows community specificity. The influences of plant litter on seed germination and seedling growth of Larch Siberian forest in the Altai Mountains were investigated through two simulated experiments including litter coverage and litter aqueous extracts. In the litter coverage experiment, three litter coverage methods including above (D), below (S) and in the middle (Z) of litter were set with the litter coverage thickness of 0, 1, 2, and 4 cm, while two aqueous extract obtained methods using the air-dried litter and litter ash after fir were used with the concentration of 10%, 40%, 80% and 100% in the present study. Results showed that: the aqueous extracts obtained using the air-dried litter restrained the seed germination, while the aqueous extracts obtained using litter ash improved the seed germination. Compared with other litter concentration, the influences of 100% concentration reach highest. The seed germination rate, seed germination potential and vital index under the treatment of seeds above the litter coverage were highest, which were significantly higher than other treatments. The above-ground biomass was significantly higher and the inhibition index of below-ground bio-mass was significantly lower under the treatment of seed above the litter with thin litter cover-age (S1) compared to other litter coverage treatments. These results indicated that the litter aqueous extract and the litter coverage had a combined effect on the seed germination and seedling growth of Siberian larch forest. Fire disturbance could promote seed germination by modifying the adverse effects of litter aqueous extracts and litter coverage, and thus plays an important role in the regeneration of Siberian larch in the Altai Mountains.

Effect of cold stratification on the temperature range for germination of Pinus koraiensis

Germination at low spring temperatures may offer a competitive advantage for the growth and survival of plant species inhabiting temperate forest ecosystems.Pinus koraiensis is a dominant species in temperate forests of northeastern China.Its seeds exhibit primary morphophysiological dormancy following dispersal in autumn,limiting natural or artificial regeneration:direct seeding and planting seedlings in spring.The aim of this study was to determine the optimum cold stratification temperature that induces germination to increase towards lower temperatures.Seeds from two populations(Changbaishan and Liangshui)were cold stratified at 0,5 and 10℃.Germination to incubation temperatures(10/5,20/10,25/15 and 30/20℃;14/10 h day/night)were determined after 2 and 4 weeks,and 5.5 and6.5 months of cold stratification.After 5.5 months,approximately 68-91%of seeds from both populations germinated at incubation temperatures of 25/15℃and 30/20℃,regardless of cold stratification temperatures.When the cold stratification temperature was reduced to 0℃and the period increased to 6.5 months,germination at 10/5℃significantly improved,reaching 37%and 64%for the Changbaishan and Liangshui populations,respectively.After 6.5 months of cold stratification,there was a significant linear regression between cold stratification temperatures and germination at10/5℃.The range in temperatures allowing for germination gradually expanded to include lower temperatures with decreasing cold stratification temperatures from 10 to 5℃and further to 0℃.

Germinated brown rice relieves hyperlipidemia by alleviating gut microbiota dysbiosis

Hyperlipidemia is a frequent metabolic disorder that is closely associated with diet. It is believed that brown rice, containing the outer bran layer and germ, is beneficial for the remission of hyperlipidemia. This study established a rat model of hyperlipidemia by feeding a high-fat diet. The hypolipidemic potential of germinated brown rice(Gbrown) and germinated black rice(a germinated black-pigmented brown rice, Gblack) were explored in the model rats, mainly in the aspects of blood lipids, lipases, apolipoproteins, and inflammation. The gut microbiota in hyperlipidemic rats receiving diverse dietary interventions was determined by 16S rDNA sequencing. The results showed that the intervention of Gbrown/Gblack alleviated the hyperlipidemia in rats, evidenced by decreased TC, TG, LDL-C, and apolipoprotein B, and increased HDL-C, HL, LPL, LCAT, and apolipoprotein A1. Gbrown/Gblack also weakened the inflammation in hyperlipidemia rats, evidenced by decreased TNF-α, IL-6, and ET-1. In addition, 16S rDNA sequencing revealed that the diet of Gbrown/Gblack elevated the abundance and diversity of gut microbiota in hyperlipidemia rats. At the phylum level, Gbrown/Gblack decreased Firmicutes, increased Bacteroidetes, and decreased the F/B ratio in hyperlipidemia rats. At the genus level, Gbrown/Gblack decreased Streptococcus and increased Ruminococcus and Allobaculum in hyperlipidemia rats. Some differential microbial genera relating to lipid metabolism were also determined, such as the Lachnospira and Ruminococcus in the Gblack group, and the Phascolarctobacterium, Dorea, Turicibacter, and Escherichia-Shigella in the Gbrown group. Notably, the beneficial effect of Gblack was stronger than Gbrown. To sum up, the dietary interventions of Gbrown/Gblack contributed to the remission of hyperlipidemia by alleviating the dysbiosis of gut microbiota.

Observation of Flowering Process of Grape(Vitis vinifera L.)—Insight into the Starting of Pollination of Flower Hiding in Calyptras(Cap)

It is generally agreed that many Vitis vinifera L.cultivars are self-fertile,where self-pollination often occurs before capfall in a process called cleistogamy.Therefore,it is difficult to identify the right time to remove stamens before self-pollination during the cross-breeding of grape.For this paper,we observed the process of grape flowering and measured the pollen viability and stigma receptivity of grape flowers of‘Shine Muscat’in order to identify the starting time of self-pollination before capfall and to provide useful information for improving the efficiency of cross-breeding.The results demonstrate that the anther is not cracked during the visible clusters and separated clusters stages.Meanwhile,in the separated floral buds,flowering begins,and full bloom stages,the pollen viability is 60.7%,73.2%and 80.3%,respectively;however,at the berry set stage,pollen viability drops to zero.The top of the mature stigma is composed of a layer of nearly cylindrical papillary cells,and the stigma receptivity for pollen changes with the development of flowers:in particular,no reaction was observed in the visible clusters stage;weak positive reaction at the separated clusters stage;strong positive reaction at the separated floral buds,flowering begins,and full bloom stages;and no reaction at the berry set stage.In the separated floral buds stage,pollen tubes were seen germinating in the style.In the flowering begins stage,more pollen tubes were observed at the entry of the ovary.During the full bloom stage,most pollen tubes elongated into the ovary base and some entered the pearl hole.At the berry set stage,newborn endosperm nucleus could be seen in the ovule.From the above,we can conclude that the initiation time of closed fertilization for‘Shine Muscat’grape can be judged as the separated floral buds stage,and it is best to discard the stamen before the separated floral buds stage when conducting cross-breeding.

Germination Quality Prognosis: Classifying Spectroscopic Images of the Seed Samples

One of the most critical objectives of precision farming is to assess the germination quality of seeds.Modern models contribute to thisfield primarily through the use of artificial intelligence techniques such as machine learning,which present difficulties in feature extraction and optimization,which are critical factors in predicting accuracy with few false alarms,and another significant dif-ficulty is assessing germination quality.Additionally,the majority of these contri-butions make use of benchmark classification methods that are either inept or too complex to train with the supplied features.This manuscript addressed these issues by introducing a novel ensemble classification strategy dubbed“Assessing Germination Quality of Seed Samples(AGQSS)by Adaptive Boosting Ensemble Classification”that learns from quantitative phase features as well as universal features in greyscale spectroscopic images.The experimental inquiry illustrates the significance of the proposed model,which outperformed the currently avail-able models when performance analysis was performed.

Effects of polyamines on the early development of cystocarps,spore release,survival,and germination rate of Gracilariopsis lemaneiformis

Three polyamines(PAs)(spermidine(Spd),spermine(Spm),and putrescine(Put))were used as growth regulators to the marine macroalgae Gracilariopsis lemaneiformis and to female gametophyte and reproductive tissues(cystocarps were constructed),which led to early maturation of cystocarps and spore release.Laboratory cultivation revealed that exogenous PA application accelerated the development of cystocarps,and the mean sporeling growth rate was 20%–50%/d during the initial week of cultivation.The spore count(SC),survival rate(SR),and germination rate(GR)of G.lemaneiformis showed different responses to PA(10-6 mol/L and 10-3 mol/L)treatments under different temperatures(18,26,and 34℃),light intensities(30,60,and 90μmol photons/(m^(2)·s)),salinities(25,30,and 35),and nutrient levels(25꞉2.5,50꞉5.0,and 75꞉7.5μmol/L NH4Cl꞉K2HPO4),and the optimal conditions were 26℃,light intensity of 60μmol/(m^(2)·s),salinity of 35,and nutrient level of 50꞉5.0μmol/L NH4Cl꞉K2HPO4.Under the optimum conditions,the SC per cystocarp increased by 82.38%,and the spore SR and GR increased by 33.07%and 46.44%,respectively.Each experiment lasted for 7 days,with the highest SC on Day 4 and plateauing on Day 7.The results indicate that PAs could promote the early maturation,spore release,survival,and germination of G.lemaneiformis under laboratory conditions.

Seed Priming Improves Enzymatic and Biochemical Performances of Rice During Seed Germination under Low and High Temperatures

As an abiotic stress,adverse germination temperatures cause serious disruptions in physiological and biochemical processes involved in seed germination.Using a factorial experiment,we examined the effects of different seed priming treatments on enzymatic and biochemical performances of rice seed germination under different temperatures.Each of the rice genotypes(Hashemi,Sadry-domsefid,IRON-70-7053-7 and NORIN-22)was primed with hydro-hardening,KCl,CaCl2 and ascorbic acid(AsA)and without a priming agent as a control at low(15℃),optimum(25℃)and high(35℃)germination temperatures.The results showed that the enzymatic and biochemical performances of all the rice genotypes were affected by the seed priming agents,especially under the low germination temperature.At 15℃,seed priming with AsA was found to be the best agent for the activities of amylase,α-amylase,catalase(CAT),peroxidase(POX),ascorbate peroxidase(APOX)and superoxide dismutase(SOD)as well as the content of soluble sugars in the NORIN-22 genotype,and for protease activity and soluble protein content in the IRON-70-7053-7 genotype.SOD at the low germination temperature and CAT,POX and protease at the optimum and high germination temperatures were the most important enzymes in occurrence of germination potential in terms of seedling length,vigor index,normal seedling rate and germination rate.Under the priming agents,the highest changes in normal seedling rate were observed at the low and optimum germination temperatures by AsA priming in the Hashemi and NORIN-22 genotypes,and at the high germination temperature under KCl priming in the Hashemi genotype.

Responses of maize germination,root morphology and leaf trait to characteristics of lead pollution:a case study

On base of the content of Pb in the soil under different land use patterns in Lanping Lead-zinc mining area,Yunnan in southwest China,the root morphology and leaf traits of maize in different concentration Pb(20,40,60,80,100,150,200,500,1000,2000,3000 mg/L)were analyzed.The results showed that maize germination rate,germination vigor and growth index decreased with the increase of Pb concentration.The root length,surface area of maize increased by 0.21%-81.58%,8.99%-73.43%,1.50%-77.37%,respectively,under 20-500 mg/L Pb concentration.However,these parameters under 1000-3000 mg/L Pb concentration decreased by 37.86%-553.54%,44.99%-766.16%,55.99%-92.81%,respectively,and these lowest value appeared in 3000 mg/L Pb treatment.The root volume of maize increased by 4.57%-89.25%in 20-80 mg/L Pb concentration,and it decreased with the increase of Pb concentration when the Pb concentration was higher than 80 mg/L and decreased by 94.13%in 3000 mg/L Pb.The root surface area and length of 0.50-1.00 diameter class were higher than those of other diameter classes,and these value of maize under 500 mg/L Pb were higher than those of other concentrations.The length and perimeter of maize leaves with the highest value of 220.36 and 962.68 mm,respectively appeared in 60 mg/L Pb treatment.The leaf width and area of maize with the highest value of 15.68 mm and 2448.31 mm^(2),respectively,appeared in 40 mg/L Pb treatment,which indicated that the leaf traits of maize were promoted by low concentration Pb and inhibited by high concentration Pb.

The Genetic and Biochemical Mechanisms Underlying Cereal Seed Dormancy

The crop seeds have been a staple food for humans,and seed yield is important for sustaining agriculture development and enhancing human adaptability to food risks.The phenomenon of pre-harvest sprouting(PHS),caused by seed dormancy deficiency,and the phenomenon of low seedling emergence caused by seed deep dormancy,will lead to a reduction in agricultural production.Therefore,it is particularly important to understand the regulation mechanisms of seed dormancy.There are many studies on the regulation of seed dormancy in rice,but there are few studies on the regulation of seed dormancy in other crops,and the research on its mechanism is not thorough enough.In this paper,we comprehensively summarize the regulation mechanisms of cereal seed dormancy,including rice,barley and wheat,discussing the integral mechanism of seed dormancy.This information should provide new insights for developing versatile cultivated lines to improve crop yield and economic benefits.

Remediation of oily soil using acidic sophorolipids micro-emulsion

A sophorolipids(SLs)micro-emulsion in Winsor type Ⅰ form was used for crude oil contaminated soil washing treatment.The micro-emulsion shows higher oil removal rate than SLs aqueous solution and diesel oil.The type Ⅰ micro-emulsion with w(SLs)=6%,w(NaCl)=1%,w(diesel)=13.36% gave a high oil removal rate of 95.6% and the eluate remained in type Ⅰ state.The recovered oil showed lower viscosity,mainly caused by the entering of diesel from the micro-emulsion phase into the oil phase and the lower removal rate of the heavier components,such as the resin and asphaltene.The initial heavily saline-alkaline soil changed into mildly saline-alkaline state after washing treatment,favoring the germination and growth of plants,with ryegrass showing better germination and growth effect than alfalfa.The ryegrass showed good phytoremediation effect on the contaminated soil after SLs micro-emulsion washing.The combination process of SL micro-emulsion washing and ryegrass phytoremediation is prospective for oily soil treatment.

Impact of ZnSO_(4)^(-)and ZnO Nanoparticles on Seed Germination and Seedling Growth of Lettuce

Micronutrient nanoparticles(NPs)are currently an option for chemical fertilization and biostimulation in crops.However,there is little information on the phytotoxic or biostimulatory effects of NPs at low concentrations of some elements,such as Zn.In this study,the effect of low concentrations of Zn oxide(ZnO)NPs on germination,growth variables,and nutritional attributes of lettuce(Lactuca sativa L.)was evaluated in comparison to Zn sulfate.Romaine lettuce seeds were treated with ZnSO_(4)^(-)×7H_(2)O and ZnO NPs at Zn molar concentrations of 1×10^(−3),5×10^(−3),1×10^(−4),5×10^(−4),1×10^(−5),5×10^(−5),1×10^(−6),and 5×10^(−6).The seeds treated with ZnSO4−at 5×10^(−6)registered the highest radicle length,73%more than the control treatment.The seeds treated with ZnSO4−at 5×10^(−3)registered the lowest values,with 50%less than the control treatment.ZnO NPs at 5×10^(−6)significantly increased content of chlorophyll A and B and total phenolics.These results indicate the possible existence of a mechanism related to the intrinsic nanoparticle properties,especially at low concentrations.