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Effect of biochar and bacterial endophytes on salinity tolerance in oats (Avena sativa L.)
(Punjab Agricultural University, 2023) Arshdeep Kaur; Gupta, Namarta
The present investigation was carried out to study the effect of biochar and plant growth-promoting bacterial endophytes for salt tolerance in oats (Avena sativa L.). Forty four morphologically distinct salinity-tolerant endophytic bacteria were isolated from the leaf, stem and root samples of oats on nutrient agar with 2.5% NaCl and screened for the production of ammonia, auxins, siderophore and HCN; solubilization of Ca3(PO4)2, ZnO, Zn3(PO4) and ZnCO3 and salt tolerance up to 12% NaCl. Bacterial isolates showing high salt-tolerance and plant growth-promoting traits were selected and tested for growth promotion of oats on 1% H2O agar plates. Three potential isolates were identified based on polyphasic approach as Enterobacter quasiroggenkampii O1SE4, Bacillus inaquosorum O3SE2 and Bacillus safensis O4SE1. The SEM analysis showed the colonization of the plant tissues by all the three bacterial strains. Total 25 genotypes were screened for germination parameters viz. percent germination, shoot length, root length, seedling length, fresh weight, dry weight, vigour index I and II, proline, SOD, POD and CAT under salt stress conditions and were grouped into highly salt tolerant, moderately salt tolerant, moderatly salt sensitive and highly salt sensitive. Among seed treatments, the combination of biochar (2%) and Bacillus safensis maximally improved the above parameters as compared to the other treatments of Enterobacter quasiroggenkampii, Bacillus inaquosorum and biochar (1%). The evaluation of biochar and bacterial strains was done in two salt tolerant and two salt sensitive genotypes grown in the pots. The highest plant height, SLW, NAR were observed with the bacterial treatment (Bacillus safensis) + biochar (2%). Among biochemical parameters chlorophyll, carotenoid, total soluble sugar, starch, total soluble protein and free amino acids along with activities of antioxidant enzymes SOD, POD and CAT were enhanced by the application of Bacillus safensis and biochar (2%). Na+/K+/Ca2+/Mg2+ homeostasis was maintained by biochar and bacteria application. In conclusion, it is stated that the combined use of biochar and halotolerant endophytic bacteria can be used for improving the crop growth under salt stress in oats.
Embargo
Evaluation of morpho-physiological and metal accumulation potential of Salix alba L. and Toona ciliata M. Roemer grown on heavy metal contaminated soils
(Punjab Agricultural University, 2022) Ravneet Kaur; Sharma, Rajni
The present investigations were carried out to study the effect of lead (Pb), cadmium (Cd) and their combinations (Pb+Cd) on morpho-physiological and metal accumulation potential of Salix alba and Toona ciliata during 2020 and 2021. Heavy metals induce negative effect on morphological and biomass attributes of both species, but Toona showed better survival percentage (>95%) than Salix (<55%) even at higher concentrations of Pb300 and Cd25. The accumulation of proline, total soluble sugars, total soluble proteins along with increased antioxidant enzyme activities are responsible to enhance tolerance in both species. On the basis of phytoremediation efficiency evaluation factors such as bioconcentration factor (BCF) and translocation factor (TF), Salix alba can be categorized as excluder plant for Pb and Cd with higher metal accumulation in roots than shoots (BCF>1, TF<1), while Toona ciliata can be categorized as hyperaccumulator with more Pb and Cd accumulation in the shoots than roots (BCF>1 and TF>1). Further, heavy metal translocation and accumulation decreased in combinations as compared to single element application suggesting the antagonistic relationship among both metals. Pb and Cd negatively affect the plant nutrient content either by affecting their translocation or by decreasing nutrient availability in soils. Anatomical studies showed significant alterations in stomatal pore size, stomatal density and trichome density due to heavy metal toxicity in both Salix and Toona. Field emission scanning electron microscopy and energy dispersive x-ray spectroscopy (FESEM-EDS) results confirmed the Pb and Cd accumulation sites in the leaves and root tissues of plants. Fourier transformed infrared (FTIR) spectroscopy analysis revealed that Pb and Cd accumulation in plants induced changes in carboxy, amino, hydroxyl and phosphate groups that ultimately caused alteration in physiological functioning in plants. Conclusively, both Salix alba and Toona ciliata have potential to be used as remediation species for Pb and Cd contaminated soils.
Open Access
EVALUATION OF MORPHO-PHYSIOLOGICAL AND METAL ACCUMULATION POTENTIAL OF Salix alba L. AND Toona ciliata M. Roemer GROWN ON HEAVY METAL CONTAMINATED SOILS
(Punjab Agricultural University, Ludhiana, 2022) Ravneet Kaur; Sharma, Rajni
The present investigations were carried out to study the effect of lead (Pb), cadmium (Cd) and their combinations (Pb+Cd) on morpho-physiological and metal ccumulation potential of Salix alba and Toona ciliata during 2020 and 2021. Heavy metals induce negative effect on morphological and biomass attributes of both species, but Toona showed better survival percentage (>95%) than Salix (1, TF1 and TF>1). Further, heavy metal translocation and accumulation decreased in combinations as compared to single element application suggesting the antagonistic relationship among both metals. Pb and Cd negatively affect the plant nutrient content either by affecting their translocation or by decreasing nutrient availability in soils. Anatomical studies showed significant alterations in stomatal pore size, stomatal density and trichome density due to heavy metal toxicity in both Salix and Toona. Field emission scanning electron microscopy and energy dispersive x-ray spectroscopy (FESEM-EDS) results confirmed the Pb and Cd accumulation sites in the leaves and root tissues of plants. Fourier transformed infrared (FTIR) spectroscopy analysis revealed that Pb and Cd accumulation in plants induced changes in carboxy, amino, hydroxyl and phosphate groups that ultimately caused alteration in physiological functioning in plants. Conclusively, both Salix alba and Toona ciliata have potential to be used as remediation species for Pb and Cd contaminated soils.
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Effect of micronutrients on carbohydrate metabolism and grain quality in sweet corn (Zea mays L.)
(Punjab Agricultural University, 2023) Harmanjot Kaur; Gupta, Namarta
The present research was performed to study the ―Effect of micronutrients on carbohydrate metabolism and grain quality in sweet corn (Zea mays L.)‖. The investigations were carried out in two experiments. The first experiment was carried out under laboratory conditions and second one is field experiment. In the laboratory experiment, seeds of sweet corn were soaked in different concentration of micronutrients and allowed to germinate according to cigar roll method. Total twenty treatments were given with different combinations of iron sulphate, zinc sulphate and manganese sulphate. The observations on physiological and biochemical parameters of seedling were recorded after seven days of treatment. All the seed treatments with micronutrients significantly improved vigour parameters with respect to control. Percent germination, shoot length, root length and vigour index was higher in seeds treated with T9 (0.2% FeSO4 and 0.5% ZnSO4) and T7 (0.2% FeSO4 and 0.2% ZnSO4). The biochemical parameters viz. total soluble sugars, starch content and amylase activity was enhanced maximally by the T7 (0.2% FeSO4 + 0.2% ZnSO4), followed by T9 (0.2% FeSO4 and 0.5% ZnSO4), T8 (0.5% FeSO4 and 0.2% ZnSO4) and T10 (0.5% FeSO4 + 0.5% ZnSO4 micronutrient treatments. In Field experiment, for morpho-physiological parameters, data was collected after 30DAS, 60DAS and 90 DAS in year 2020 and 2021. Foliar spray of micronutrient treatments enhanced vegetative and reproductive growth parameters. Increased plant height, leaf area index, leaf weight ratio, leaf area ratio, specific leaf weight, specific leaf area, crop growth rate, relative growth rate, net assimilation rate were observed after foliar spray with micronutrients. Maximum increase was recorded in T9 (0.2% FeSO4 + 0.5% ZnSO4) followed by T7 (0.2% FeSO4 + 0.2% ZnSO4) and T8 (0.5% FeSO4 and 0.2% ZnSO4). Cob length, cob girth, grain weight and grain yield, it was observed that higher increase was recorded in treatment T9 (0.2% FeSO4 + 0.5% ZnSO4) and T7 (0.2% FeSO4 + 0.2% ZnSO4). Biochemical estimations in grains exhibited strong correlation among micronutrients and grain quality. Among biochemical parameters, T9 (0.2% FeSO4 + 0.5% ZnSO4) and T7 (0.2% FeSO4 + 0.2% ZnSO4), increased chl a, chl b, carotenoids, total chlorophyll and carotenoid content along with higher sucrose synthase and sucrose-6-phosphate synthase activities as compared to other treatments and control. Total soluble sugars, total starch content, and free amino acids were significantly higher in T9 (0.2% FeSO4 + 0.5% ZnSO4), followed by T7 (0.2% FeSO4 + 0.2% ZnSO4). Total soluble proteins, proline content and free amino acids were maximum in treatment T8 (0.5% FeSO4 and 0.2% ZnSO4), followed by T7 (0.2% FeSO4 + 0.2% ZnSO4) and T9 (0.2% FeSO4 + 0.5% ZnSO4). Overall, T9 (0.2% FeSO4 + 0.5% ZnSO4), followed by T7 (0.2% FeSO4 + 0.2% ZnSO4) and T8(0.5% FeSO4 and 0.2% ZnSO4) recorded better results as compared to other micronutrient treatments for improving growth, yield and grain quality in sweet corn. Seed treatment with T20 (0.5% FeSO4, 0.5% ZnSO4 and 0.5% MnSO4) and T19 (0.2% FeSO4, 0.2% ZnSO4 and 0.2% MnSO4) recorded less improvement in growth than other treatments as compared to control.
Embargo
Physiological and biochemical variability in Brassicas under conservation tillage
(Punjab Agricultural University, 2023) Mamta Pal; Sharma, Pushp
Drought is a multifarious stress affecting almost all the growth stages and yield in Brassicas. Present investigation was carried out to assess germination and tolerance to moisture stress induced by different concentration of PEG in laboratory. Comparative germination studies for drought tolerance using distilled water as control and six osmotic potentials (-0.2, -0.4, -0.6, -0.8, 1.0 and -1.2 MPa) induced by PEG 6000 were carried out under controlled condition. All the germination traits suffered a decline over control with increased stress levels except to mean germination time. The three varieties GSC-7 (B.napus), Giriraj (B. juncea) and PC-6 (B. carinata) exhibited better performance for germination and related traits in the induced six stress levels over the control which was further endorsed by PCA and HCA. Field trials were conducted for 2 years to study the morpho-physiological and biochemical variability in Brassicas under conservation tillage. Twelve varieties/strains of the three Brassica species: B.napus (GSC-7, GSC-6, GSC-21, GSC-22 and I-75), B. juncea (JC-210-325, CJRD-1261, PBR-357, Giriraj and RLC-3) and B. carianata (PC-5 and PC-6) were selected for field evaluation under split-split plot design with 3 irrigation regimes: moisture stress, restricted stress and normal irrigation along with two tillage treatment: conventional (CT) and zero tillage (ZT). ZT delayed the phenophases over CT irrespective of irrigation regimes. Flowering duration, siliquing duration and reproductive phase were longer under ZT over CT. At studied 3 crop stages physiological parameters, i.e. SPAD, NDVI, photosynthetic pigments, hill reaction activity increased with ZT. Similar increased trend was noticed in RWC, LWR however RSD and WSD declined. Membrane stability in the varieties/ strains was higher under ZT with lowered membrane injury. Antioxdative enzymes and biomolecules were upregulated under stress, but were more in CT relative to ZT. Total carbohydrate were more under ZT and reached maximum at flowering stage whereas proteins under CT and were highest at siliquing stage. Assimilation improved with irrigation regimes. ZT was also beneficial in improving oil content (≤1%), seed N content and N in stem and chaff. Overall, GSC-7, a canola variety of B.napus, non-canola varieties (PBR-357 and Giriraj), canola variety (RLC-3) of B. juncea and non-canola determinate variety PC-6 of B. carianata registered more siliqua length, seed/siliqua, more developed and lesser shriveled seed/siliqua with ZT. The elite varieties possessed higher tolerance indices viz. DTI≥ 0.8, YSI≥0.79 and DTE≥ 70% under both the tillage treatments.
Restricted
Mechanism of salinity tolerance in elite wheat (Triticum aestivum L.) germplasm
(Punjab Agricultural University, Ludhiana, 2023) Choudhary, Anuj; Nirmaljit Kaur
The current research work on “Mechanism of salinity tolerance in elite wheat (Triticum aestivum L.) germplasm” was conducted to illuminate the genetic potential of wheat lines for salt stress tolerance. The study was undertaken at the laboratory and experimental area of Department of Botany and Department of Plant Breeding & Genetics, Punjab Agricultural University, Ludhiana during 2018-19 and 2019-20. A set of 278 wheat lines was procured from Department of Plant Breeding & Genetics was initially screened under lab condition. Selected lines were subjected to various salt stress concentrations viz. 0 mM, 30 mM, 60 mM, 90 mM, 120 mM, 150 mM and 180 mM NaCl. It was followed by screening of all wheat lines at standardized 150 mM salt stress condition for shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight and vigor index. They were grouped as 11 highly salt tolerant, 57 salt tolerant, 89 moderately salt tolerant, 116 salt sensitive and 5 highly salt sensitive. Twenty lines were selected for precise evaluation under the naturally salt affected field conditions and the controlled condition on the basis of morphological, physiological and yield attributes. The EC value of the controlled plots ranged between 0.41 to 0.81 m mhos cm-1 whereas the EC value of saline plots was between 0.79 and 1.71 m mhos cm-1. Among the 20 wheat lines, the LTP 187 (linked top cross population), LTP 210, and LTP 221 performed better for all the traits under field conditions and therefore, these are suggested for the future wheat breeding improvement programs for salt stress. Three SNPs (SNP_986175, SNP_ 2264905 and SNP_4910157) were found significantly associated with salt stress. Significantly associated SNPs were mainly observed on chromosomes 1A, 1B, 3A, 3B, 5A, 5B, 6B, 7A and 7D and therefore these SNPs can be used in marker assisted breeding programs for improving thousand grain weight in wheat.
Open Access
Physiological and biochemical basis of high temperature stress tolerance and its amelioration in bell pepper (Capsicum annuum L. var. grossum)
(Punjab Agricultural University, Ludhiana, 2020) Tejinder Preet; Ghai, Navita
The present investigation was carried out to evaluate the role of plant growth regulators viz. Salicylic acid (SA) and 24-epibrassinolide (EBR) on the physiological and biochemical parameters of bell pepper (Capsicum annuum L.). Two cultivars of bell pepper viz. hybrid Indra and variety Royal Wonder were selected for the study along with Punjab Sindhuri (hot pepper) used as a tolerant check for heat tolerance. Three concentration of each growth regulator, SA (0.10 mM, 0.20 mM and 0.50 mM) and EBR (0.05 µM, 0.10 µM and 0.20 µM) were applied in the form of foliar spray to both the cultivars at three growth stages, vegetative bud stage (30 DAT), reproductive stage (60 DAT) and post-reproductive stage (90 DAT). All the concentrations of PGRs were effective in imparting thermotolerance in terms of improved growth parameters (plant height, plant spread and leaf area), membrane thermostability, photosynthetic parameters (total chlorophyll content, carotenoid content and hill reaction activity), levels of total soluble sugars, starch, proteins, proline, enhanced antioxidant system (CAT, APX, POX, SOD and GR), fruit parameters (fruit length, fruit width, pericarp thickness and fruit chlorophyll). Application of SA and EBR resulted in reduced lipid peroxidation in leaf tissue and cellulase activity in pedicel of flowers, causing more retention of flowers, increased pollen viability and fruit set percent even at high temperature ultimately resulting in improved yield. Appearance of some new bands during SDS-PAGE of proteins in treated plants pointed towards the foundation of HSPs which helped the plants to survive under stressful conditions. Foliar spray of 0.10 µM EBR in hybrid Indra and 0.20 mM in variety Royal Wonder done at reproductive stage (60 DAT) and vegetative bud stage (30 DAT), respectively, were most effective in ameliorating the effects of high temperature stress.
Open Access
Characterization of morpho-physiological and biochemical trait for heat tolerance in Indian mustard (Brassica juncea L. Czern. & Coss)
(Punjab Agricultural University, Ludhiana, 2020) Priya; Sharma, Pushp
The present investigation “Characterization of morpho-physiological and biochemical trait for heat tolerance in Indian mustard (Brassica juncea L. Czern. & Coss)” was conducted in timely and late planted set of forty nine advanced breeding genotypes in two rabi seasons (2016-17 and 2017-18) at Punjab Agricultural University, Ludhiana and Dr. JC Bakhshi, Regional Research Station, Abohar which were further evaluated in the temperature gradient tunnels (TGT), Department of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana with the objective to standardize the screening techniques for heat tolerance based on morpho-physiological, biochemical and yield traits. Experiments were laid in factorial randomized block design. High temperature experienced by late planting led to reduced phenological duration at both locations while genotypes attained late maturity in TGT (13 days). Physiological traits like chlorophyll content, SPAD value, LAI and PAR (%) increased from vegetative to flowering stage followed by decline at siliquing stage whereas chlorophyll and SPAD value increased in TGT at flowering and siliquing stage. Lower CTD, decline in RWC (23.0%), LWR (12.0%) and MS (36.3%) while increase in WSD (16.8%), RSD (15.4%) and MI (18.1%) under delayed sowing. The high demand for utilizing stem reserve but lower accumulation and translocation of photoassimlates led to the imbalance between source to sink translocation in delayed planting however up regulation of antioxidative enzymes and non enzymatic antioxidative biomolecules imparted thermo tolerance. Positive association of seed yield existed at two locations with phenological durations, BY, HTI and HSI. Selection criteria of seed yield reduction (<30%), lower HSI (≤1) and higher HTI (≥1), over the years at two locations rated PCR-3, CSR-158, HLM-4113-2, ELM-38, CSR-1163, JMG-244 and CM-21-16promising. Three genotypes PCR-3, ELM-38, CSR-1163 were identified heat tolerant at two locations and in temperature gradient tunnels.
Open Access
Evaluation of Elymus semicostatus germplasm from lahaul valley as potential donor for wheat improvement
(Punjab Agricultural University, Ludhiana, 2020) Antul Kumar; Sharma, Rajni
The present investigation entitled “Evaluation of Elymus semicostatus germplasm from Lahaul valley as potential donor for wheat improvement’’ was carried out to evaluate the in depth botanical characterization, their physiological responses in different water environments and hybridization attempts to mobilize the useful traits into wheat. The plant material was collected from Lahaul valley (Lahaul-Spiti, HP) and its adjoining regions. The field experiments were conducted at the research farm of Wheat section, Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana. The E. semicostatus showed morphological resemblance with three other members of the genus Elymus viz: E. longiaristatus, E. repens and E. dahuricus. Forty distinguishing characters were marked for each species. The E. semicostatus showed morphological adaptation for drought tolerance such as dense pubescence, awn length and colour, leaf waxiness and pigmentation on other plant parts. The germplasm set was narrowed down to 34 accessions on the basis of their intra-specific variation during field evaluation. Selected 34 accessions set was evaluated for drought tolerance traits under field conditions. Vernalization treatment for 4-6 weeks at 4-8˚C and 8hr photoperiod was provided to germinated seedlings in December and January for about 6-7 hours to synchronize flowering with hexaploid wheats. The drought conditions were created by withholding irrigation (rainfed), regular recommended irrigation and restricted irrigation (1-2 times after transplantation). The morpho-physiological traits such as plant height, flowering days, spike length, leaf area, tiller numbers, chlorophyll contents at different stages and relative water content were observed at anthesis. For morpho-physiological parameters, the NBPAU28 showed maximum plant height (133cm), spike length (25.67 cm), tiller number (33.17) and leaf area (30.32cm). The accessions NBPAU7, NBPAU13, NBPAU14 and NBPAU28 were best for plant height, spike length, leaf area, whereas NBPAU1, NBPAU6, NBPAU15 and NBPAU27 performed well under drought conditions. The chlorophyll content was significantly increased during anthesis in all accessions and then declined, but it maintains low chlorophyll content upto harvesting stage. In an attempt to cross the species with hexaploid wheat, embryo rescue was attempted. A total of 991 caryopses were obtained from the crosses of three consecutive seasons from 2017 to 2018. Only 20 hybrid plants could be established on account of the desiccating conditions at PAU, which probably contributed to low survival rate. The surviving hybrid plants never reached booting stage at PAU, Ludhiana. The E. semicostatus can be a potential donor for the drought tolerance traits and more detailed studies on overcoming pre and post fertilization barriers need to be done for introgressing useful traits into wheat cultivars for wheat improvement.

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