Physio-biochemical Attributes Research Articles

Copper Oxide Nanoparticles Induced Growth and Physio-Biochemical Changes in Maize (Zea mays L.) in Saline Soil.

Research on nanoparticles (NPs) is gaining great attention in modulating abiotic stress tolerance and improving crop productivity. Therefore, this investigation was carried out to evaluate the effects of copper oxide nanoparticles (CuO-NPs) on growth and biochemical characteristics in two maize hybrids (YH-5427 and FH-1046) grown under normal conditions or subjected to saline stress. A pot-culture experiment was carried out in the Botanical Research Area of "the University of Lahore", Lahore, Pakistan, in a completely randomized design. At two phenological stages, both maize hybrids were irrigated with the same amount of distilled water or NaCl solution (EC = 5 dS m-1) and subjected or not to foliar treatment with a suspension of CuO-NPs. The salt stress significantly reduced the photosynthetic parameters (photosynthetic rate, transpiration, stomatal conductance), while the sodium content in the shoot and root increased. The foliar spray with CuO-NPs improved the growth and photosynthetic attributes, along with the N, P, K, Ca, and Mg content in the roots and shoots. However, the maize hybrid YH-5427 responded better than the other hybrid to the saline stress when sprayed with CuO-NPs. Overall, the findings of the current investigation demonstrated that CuO-NPs can help to reduce the adverse effects of salinity stress on maize plants by improving growth and physio-biochemical attributes.

Impact of ZnO nanopriming on physiological and biochemical traits of wheat (Triticum aestivum L.) seedling

To ascertain the ideal dosage of ZnO NPs (Zinc Oxide Nanoparticles), we conducted an investigation on the priming effects of varying concentrations of ZnO NPs on germination and physio-biochemical parameters of wheat. In this study, ZnO NPs were synthesized and characterized for their physico-chemical properties followed by confirmation of the formation of ZnO NPs. Throughout this study, wheat seeds were subjected to ZnO NPs at various concentrations of 5, 50, 100, 250, and 500 ppm for a period of 4 h via continuous aeration. The primed seeds were sowed in plastic bags, allowed to grow for 21 days, following which comprehensive evaluations of physio-biochemical attributes were conducted. At 250 ppm, an impressive 100% of seeds successfully germinated compared to the control group. The examined physiological factors such as shoot length, root length, and fresh as well as dry weights of leaf and root tissues all exhibited notable increases with the ascending concentrations of ZnO NP up to 250 ppm. However, beyond this threshold, at 500 ppm, these parameters experienced a decline. Inductively coupled plasma atomic absorption spectrophotometer (ICP-AAS) measurements validated the progressive increase in Zinc content in the nanoprimed seedlings, further affirming the dose-dependent trend. Zinc oxide nanoparticles notably improved key biochemical features, including elevated levels of total chlorophyll, malondialdehyde (MDA), total protein, and the accumulation of osmolytes such as proline and glycine-betaine. Additionally, the presence of ZnO NPs led to increased activity of antioxidant enzymes like superoxide dismutase (SOD) and catalase in a dose-dependent mananer. Collectively, the amassed data underscores the efficacy of the 250 ppm ZnO NPs treatment, which emerged as superior in comparison to both the control group and other administered treatments. These findings underscore the potential of ZnO NPs at a concentration of 250 ppm as a valuable seed nanopriming agent, effectively enhanced germination and robust early-stage growth in young plants.

Silicon and titanium nanoparticles modulated drought and chromium toxicity by adjusting physio-biochemical attributes and fatty acid profiles of black cumin (Nigella sativa L.).

Drought and chromium (Cr) stress are the main environmental issues affecting plant performance. Although the positive effects of silicon dioxide (SiO2) and titanium dioxide (TiO2) nanoparticles (NPs) are used as a promising strategy to control abiotic stresses; their synergic effects on controlling drought and Cr toxicity are unknown. This study aimed to investigate the effects of foliar applications of SiO2 (200 mg L-1) and TiO2 (60 mg L-1) NPs on growth, chlorophyll (Chl) content, lipid peroxidation, antioxidant enzyme, and fatty acid profile of black cumin (Nigella sativa L.) under drought (soil moisture at 50% field capacity (FC) and Cr toxicity as K2Cr2O7 at 10 mg L-1. The results showed that drought and Cr stress significantly reduced growth and Chl a + b, but increased malondialdehyde (MDA), electrolyte leakage (EL), and the activity of antioxidant enzymes. The use of NPs particularly SiO2 NPs modulated drought and Cr stress through enhancing Chl content and alleviating MDA, EL, and antioxidant activities. Under drought stress, SiO2 NPs enhanced shoot weight (26%), root weight (25%), seed yield (36%), Chl content (26%), but lowered MDA (22%), EL (14%), catalase (CAT, 32%), and superoxide dismutase (SOD, 33%) activity relative to non-NP application. The main changes in fatty acid profile corresponded to abiotic stresses, where they increased polyunsaturated fatty acids (PUFAs) but decreased monounsaturated fatty acids (MUFAs). Multivariate analysis showed that plant weight, seed yield, Cl content, and oleic acid negatively correlated with MDA, EL, antioxidant enzymes, and linoleic acid. In total, the use of SiO2 is recommended for modulating drought and Cr stress to reach the maximum seed yield of black cumin and a healthy fatty acid profile.

Arabic gum/chitosan/Zn–NPs composite film maintains the quality of Hass avocado fruit by delaying ripening and activating enzymatic defense mechanisms

Avocado fruit is a climacteric fruit that has a short life after harvest. Chitosan (Ch) and Arabic gum (AG) have a pronounced effect on the storability of fruits. This investigation aimed to determine the effect of individual or combined use of Ch and AG as well as Ch/AG enriched with 2, 4, 8% Zn–NPs on physio-biochemical attributes and antioxidant capacity of Hass avocado fruit during cold storage (7 °C). The result showed that Ch or AG alone succeeded in maintaining fruit quality of Hass fruit during cold storage. Also, combined application of Ch/AG was more effective than individual application of Ch or AG in reducing fruit weight and polyphenol oxidase activity (PPO) as well as increasing total antioxidant capacity (TAC) and malondialdehyde (MDA). Moreover, Ch/AG coating enriched with 8% Zn–NPs recorded the lowest fruit weight loss, fruit decay %, TSS fruit content, fruit firmness and improved fruit skin and pulp color significantly compared to Ch/AG and control. Coating with Ch/AG/2%Zn NPs recorded the highest peroxidase (POD) activity, while Ch/AG/8% Zn–NPs recorded the highest TAC and the lowest PPO activity. Moreover, enriched Ch/GA with Zn–NPs recorded the highest CAT and POD activity compared to the control. This study shows the efficiency of Ch/AG enriched with Zn–NPs on preserving Hass avocado fruit quality during cold storage by delaying ripening process and activating enzymatic defense mechanisms.

Trehalose Induced regulations in Physio-biochemical attributes of Helianthus annus under Lead stress

Heavy metal is a substantially severe abiotic environmental stress that is rising in many regions of the world. Current climate change circumstances and rapid industrialization increased heavy metal accumulation in soil and water. Overall, worldwide agricultural production decreased. Trehalose, a well-known plant growth regulator, is crucial in plants' responses to a variety of abiotic conditions. The Morpho-physiological and biochemical parameters were analyzed in hydroponic research to identify the possible role of trehalose in alleviating heavy metal lead acetate stress in sunflower (Helianthus annuus L.) crops. In the sole and mixed form, two Pb(C2H3O2)2 (Control and 30 micron) and one trehalose (50 M L-1) levels were used, and a half-strength Hoagland solution was used as a nutritional medium. The current study found that heavy metal stress had a significant negative impact on plant growth (root and shoot length), fresh and dry biomass, and plant water relations, as well as poor plant water relations, membrane stability, chlorophyll content, and antioxidant enzyme activities such as superoxide dismutase (SOD), peroxide (POD), ascorbate peroxide (APX), and catalase (CAT). MDA and H2O2 are the stress markers reduced by the application of trehalose. Exogenous treatment of trehalose, on the other hand, significantly mitigates the detrimental effects of metal toxicity by altering plant physiology, enhancing water relations, and providing robust antioxidant defense against heavy metal lead acetate stress. The findings of this study provide a new dimension to scientists' understanding of the beneficial usage of trehalose in plant science and offer up new research opportunities.

Application of Benzylaminopurine with Methyl Jasmonate and Epibrassinolide Improved Growth and Physio-biochemical Attributes of Strawberry (Fragaria × ananassa cv. ‘Albion’)

Application of Benzylaminopurine with Methyl Jasmonate and Epibrassinolide Improved Growth and Physio-biochemical Attributes of Strawberry (Fragaria × ananassa cv. ‘Albion’)

Morphological and biochemical variations caused by salinity stress in some varieties of Pennisetum glaucum L.

The salinity of the soil is a severe challenge to the sustainability of agricultural production. It causes significant loss in the productivity of crop plants. To overcome this problem, one of the possible solutions could be the identification and cultivation of salinity tolerant crop plants in salt affected land. Therefore, this study was designed to screen some varieties of Pearl Millet (Pennisetum glaucum L. Family Poaceae), an equally important cereal crop for food and forage, for salinity tolerance in a pot experiment. Some eighteen varieties of Pearl Millet were utilized to investigate the morphometric and biochemical variations induced by saline stress. The plants were grown for three weeks under normal conditions in sand culture in disposable PVP cups with three inches diameter. Afterwards, the plants were challenged with salinity stress (aqueous solution of NaCl applied in successive steps of 50, 100, 150 and 200 mM with Hoagland’s nutrients). The plants adopted salinity stress after one week and harvested for various physio-biochemical attributes. The results showed that the varieties YBS-93, YBS-94, YBS-95 and YDR-8-1 exhibited tolerance toward salinity stress as their shoot length, root length, biomass production and K+ was maintained under salt stress. The levels of proline contents and free amino acids in their leaves were relatively higher under salt stress as compared with other varieties. The accumulation of Na+ in theses varieties was lower as compared to other varieties under saline stress. These findings indicated their potential strategy to cope with salinity stress. While theYBS-83, YBS-98, YCMP-19 and YCMP-34 varieties among the subjected eighteen varieties of Pearl Millet were screened as most sensitive varieties to salinity stress in these experimental conditions. Because these varieties had reduction in shoot length, root length biomass production and K+. Other varieties did not show any significant success in salinity stress management. This study has provided significant preliminary screening data of morphological and biochemical aspects of eighteen varieties of Pearl Millet for their capability of salinity tolerance. Further molecular investigations are underway which will be helpful in revealing insights of the salt tolerance mechanism and signaling pathways in the screened salt tolerant varieties.

Integrative application of silicon and/or proline improves Sweet corn (Zea mays L. saccharata) production and antioxidant defense system under salt stress condition

Silicon (Si) and/or proline (Pro) are natural supplements that are considered to induce plants' stress tolerance against various abiotic stresses. Sweet corn (Zea mays L. saccharata) production is severely afflicted by salinity stress. Therefore, two field tests were conducted to evaluate the potential effects of Si and/or Pro (6mM) used as seed soaking (SS) and/or foliar spray (FS) on Sweet corn plant growth and yield, physio-biochemical attributes, and antioxidant defense systems grown in a saline (EC = 7.14dS m−1) soil. The Si and/or Pro significantly increased growth and yield, photosynthetic pigments, free proline, total soluble sugars (TSS), K+/Na+ratios, relative water content (RWC), membrane stability index (MSI), α-Tocopherol (α-TOC), Ascorbate (AsA), glutathione (GSH), enzymatic antioxidants activities and other anatomical features as compared to controls. In contrast, electrolytes, such as SS and/or FS under salt stress compared to controls (SS and FS using tap water) were significantly decreased. The best results were obtained when SS was combined with FS via Si or Pro. These alterations are brought about by the exogenous application of Si and/or Pro rendering these elements potentially useful in aiding sweet corn plants to acclimate successfully to saline soil.

28-Homobrassinolide Primed Seed Improved Lead Stress Tolerance in Brassica rapa L. through Modulation of Physio-Biochemical Attributes and Nutrient Uptake.

Brassinosteroids (BRs) influence a variety of physiological reactions and alleviate different biotic and abiotic stressors. Turnip seedlings were grown with the goal of further exploring and expanding their function in plants under abiotic stress, particularly under heavy metal toxicity (lead stress). This study's objective was to ascertain the role of applied 28-homobrassinolide (HBL) in reducing lead (Pb) stress in turnip plants. Turnip seeds treated with 1, 5, and 10 µM HBL and were grown-up in Pb-contaminated soil (300 mg kg-1). Lead accumulation reduces biomass, growth attributes, and various biochemical parameters, as well as increasing proline content. Seed germination, root and shoot growth, and gas exchange characteristics were enhanced via HBL treatment. Furthermore, Pb-stressed seedlings had decreased total soluble protein concentrations, photosynthetic pigments, nutrition, and phenol content. Nonetheless, HBL increased chlorophyll a and chlorophyll b levels in plant, resulting in increased photosynthesis. As a result, seeds treated with HBL2 (5 µM L-1) had higher nutritional contents (Mg+2, Zn+2, Na+2, and K+1). HBL2-treated seedlings had higher DPPH and metal tolerance indexes. This led to the conclusion that HBL2 effectively reduced Pb toxicity and improved resistance in lead-contaminated soil.

A Novel Nutrient- and Antioxidant-Based Formulation Can Sustain Tomato Production under Full Watering and Drought Stress in Saline Soil.

As a result of the climate changes that are getting worse nowadays, drought stress (DS) is a major obstacle during crop life stages, which ultimately reduces tomato crop yields. So, there is a need to adopt modern approaches like a novel nutrient- and antioxidant-based formulation (NABF) for boosting tomato crop productivity. NABF consists of antioxidants (i.e., citric acid, salicylic acid, ascorbic acid, glutathione, and EDTA) and nutrients making it a fruitful growth stimulator against environmental stressors. As a first report, this study was scheduled to investigate the foliar application of NABF on growth and production traits, physio-biochemical attributes, water use efficiency (WUE), and nutritional, hormonal, and antioxidative status of tomato plants cultivated under full watering (100% of ETc) and DS (80 or 60% of ETc). Stressed tomato plants treated with NABF had higher DS tolerance through improved traits of photosynthetic efficiency, leaf integrity, various nutrients (i.e., copper, zinc, manganese, calcium, potassium, phosphorus, and nitrogen), and hormonal contents. These positives were a result of lower levels of oxidative stress biomarkers as a result of enhanced osmoprotectants (soluble sugars, proline, and soluble protein), and non-enzymatic and enzymatic antioxidant activities. Growth, yield, and fruit quality traits, as well as WUE, were improved. Full watering with application of 2.5 g NABF L-1 collected 121 t tomato fruits per hectare as the best treatment. Under moderate DS (80% of ETc), NABF application increased fruit yield by 10.3%, while, under severe DS (40% of ETc), the same fruit yield was obtained compared to full irrigation without NABF. Therefore, the application of 60% ETc × NABF was explored to not only give a similar yield with higher quality compared to 100% ETc without NABF as well as increase WUE.

Zinc sulfate biofortification enhances physio-biochemical attributes and oxidative stress tolerance in rice varieties grown in zinc deficient alkaline soil

Zinc (Zn) is a crucial trace mineral with diverse roles in plants; its deficiency in edible plant parts results in micronutrient malnutrition, leading to stunted growth. Zinc deficiency in the soil is a significant factor leading to poor rice quality. This research aimed to reveal the impact of Zn biofortification on rice productivity and to introduce rice cultivars with enriched nutrients. The effects of various zinc sulfate (ZnSO4) rates viz. 100, 200, 300, 400 and 500 mM (designated as T1, T2, T3, T4 and T5, respectively) on the germination process, chlorophyll pigments, biochemical activities, and the mitigation of oxidative damage in four different rice (Oryza sativa L.) cultivars (KSK-133, Basmati-198, Basmati-515, and PK-386) grown in alkaline Zn-deficient soil were evaluated. A control without Zn application (T0) was kept for comparison. Results demonstrated that Zn treatments significantly affected the germination rates, vegetative growth, photosynthetic attributes, and enzymatic and non-enzymatic activities of all tested cultivars. Zn application significantly ameliorated the oxidative stress by increasing antioxidant enzyme activities such as catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), 2,2-diphenyl-1-picrylhydrazyl (DPPH), glutathione peroxidase, and non-enzymatic compounds (such as flavonoids, proline, phenolics, reducing sugar and non-reducing sugar, total carbohydrates, and free amino acid) in all tested cultivars. Among the application rates, ZnSO4 application at 400 mM depicted the highest values of the above-mentioned traits. Furthermore, recorded data also revealed that ZnSO4 had a significant impact on flavonoids, total carbohydrates, and phenolic contents where its application at 400 mM depicted significantly higher values than other treatments. Among the tested cultivars, Basmati-198 exhibited the highest values of flavonoids, total carbohydrates, and phenolic contents showing an increase of 134.53%, 103.57%, and 265.34%, respectively, over the average of other cultivars. In sum, ZnSO4 application at 400 mM significantly improved rice performance under alkaline conditions whereas its application at 500 mM onsets toxic effect on all tested cultivars. However, to gain a comprehensive understanding of the underlying mechanisms, further research is needed to conduct long-term field studies at the molecular level.

Improvement of physio-biochemical attributes and mitigation of salinity stress by combined application of melatonin and silicon nanoparticles in Brassica oleracea var. botrytis

Salinity is a significant abiotic stress in arid and semiarid areas, threatening global food security. This research explored the potential of silicon nanoparticles (Si-NPs) and Melatonin (MT) to alleviate salinity stress in Brassica oleracea var. botrytis. The study used varying Si-NPs concentrations viz. NP0 (distilled water), NP1 (50 mg/L), NP2 (100 mg/L), and NP3 (200 mg/L) and Melatonin following a completely randomized design (CRD). Salinity hindered the growth and phytochemical attributes of B. oleracea seedlings. However, applying Si-NPs and MT mitigated this stress. Maximum fresh root weight of seedlings was observed when seeds were primed with 80 mg/L Si-NPs under 200 mM salt concentration, and the highest root length was noted with 60 mg/L and 80 mg/L Si-NPs. Seeds primed with 40 and 80 mg/L Si-NPs displayed the highest leaf count in seedlings under 50- and 100-mM salt concentrations, respectively. At 200 mM salt concentration, 40 mg/L and 60 mg/L Si-NPs priming notably enhanced total chlorophyll contents. Relative chlorophyll contents significantly increased with Si-NPs priming of 40 mg/L, 60 mg/L, and 80 mg/L under varying salt solutions along with melatonin. Exposure to 200 mM Si-NPs led to enhanced superoxide dismutase production in plants compared to control. Si-NPs and MT supplementation notably elevated osmolyte levels in salt-stressed B. oleracea seedlings compared to other treatments. Hence, treatment of Si-NPs and MT might be effective against abiotic stress in B. oleracea. This study offers valuable insights for cultivating economically important crops in high salt-stressed agricultural lands.

Salicylic acid potential to reversing drought induced oxidative stress in Bacopa monnieri (L.) through enhancement of bioactive compound (Bacoside-A) and antioxidants including physio-biochemical attributes

Salicylic acid (SA), an eminent stress tolerance phytohormone, assists plants in dealing with abiotic stress. A pot experiment was carried out to substantiate the SA's ability to protect the medicinal herb Bacopa monnieri (L.) from exposure to water deficit. Diverse concentrations of SA (50, 75, 100, and 125 mg/l) were applied to plants as a foliar spray along with varied water levels based on reduced irrigation, WD1 (twice a week), and WD2 (once a week) against WW (once a day), with the first spray being applied after one week of water deficit treatment and the second one month later. The pool data for 2021 and 2022 demonstrated the resilience propensity of SA against water deficit in terms of oxidative markers detoxification (H2O2 and MDA) via evoking the antioxidative mechanism of plants. The activity of antioxidants (SOD, CAT, GPOX, and APOX) and amount of non-enzymatic antioxidants (ascorbic acid, total phenolics and, flavonoid) including osmolytes (proline and total soluble sugar) was upsurged after SA (75 mg/l conc.) administration under both stressed and non-stressed plants. Additionally, stressed plants also revealed a recovery in their relative water content with intensifying the membrane stability index. Besides that positive repercussion in terms of medicinally bioactive compound (bacoside-A) content was also achieved with 75 mg/l conc. of SA foliar spray in addition to WD2. Conclusively, the present investigation unraveled the attainment of SA to ameliorate the B. monnieri (L.) under water deficit stress at moderate doses (up to 100 mg/l) by boosting their deterrence mechanisms through counterbalance of the physio-biochemical attributes.

Exogenous Melatonin Modulated Drought Stress by Regulating Physio-Biochemical Attributes and Fatty acid Profile of Sweet Cherry (Prunus avium L.)

Exogenous Melatonin Modulated Drought Stress by Regulating Physio-Biochemical Attributes and Fatty acid Profile of Sweet Cherry (Prunus avium L.)

Elucidating role of melatonin foliar spray in ameliorating adverse effects of drought stress on growth and physio-biochemical attributes of Brassica rapa plants

Melatonin is tryptophan derivative, a multipurpose phytochemical that ameliorate adversity of abiotic stress on plants. However, melatonin (Mel) role in ameliorating stress in growth cycles of various plant species needs investigation. In this study, diverse concentrations of Mel (100 µM, 150 µM, and 200 µM) were applied to determine which one could effectively reduce the harmful effect of water stress on turnip (Brassica rapa) plants. B. rapa leaves and roots exhibited lower growth and increased Na+ uptake (18%, 17%) due to drought stress. However, foliar-applied Mel significantly enhanced the growth characteristics, photosynthetic pigments and total phenolics in B. rapa plants under drought stress conditions. Mel foliar supplementation to B. rapa plants increased K+ and Zn+ uptake in the leaves and roots. Mel induced growth of B. rapa plants, especially under conditions of water deficiency was found to be related with higher levels of photosynthetic pigments, total soluble sugars, total soluble proteins and total free amino acids. Therefore, it is hypothesized that exogenous Mel treatment might be useful in enhancing plants' ability to survive under water stressed conditions.

Differential response of chrysanthemums on osmolyte accumulation, chlorophyll content and growth attributes under salinity stress

Chrysanthemum is moderately sensitive to salt stress, and salinity largely affects its production. The experiment was undertaken at the research farm of the Division of Floriculture and Landscaping, ICAR-IARI, New Delhi, during the winter season. Ten chrysanthemum varieties were screened to understand their response to salt stress (150 mM NaCl) and tolerance mechanisms. Salt stress significantly affected osmolyte accumulation and physio-biochemical attributes of chrysanthemum varieties against control. Red Gold variety performed well in terms of growth and yield attributes, indicating its ability to tolerate the salt level of 150 mM NaCl. The highest leaf proline content was recorded in var. White Prolific followed by var. Tata Century. NaCl stress caused a 3/2-fold and 1/2-fold increase in the level of Na+ and K+ ions in leaf tissues of most varieties against control Shoot K+/Na+ ratio was recorded highest in variety Tata Century followed by variety Discovery. From the experiment, vars. White Prolific, Red Gold, Tata Century, and Discovery were found to be more tolerant due to better osmotic adjustments through the accumulation of proline, relative performance under salt stress for plant growth, flower yield, photosynthetic pigments and high K+/Na+ concentration to better sustain under saline condition than the susceptible varieties. PCA analysis revealed that the sum of principal components PC1 and PC2 explained 59.0% of the variations among the varieties. Plant height, chlorophyll content, and fresh weight number of branches had the highest positive loading value, i.e., ~0.7, and leaf proline content had the lowest loading value, i.e., ~0.08, indicating the strongest influence on PC1 and PC2.

Physiological Changes and Nutritional Value of Forage Clitoria Grown in Arid Agro-Ecosystem as Influenced by Plant Density and Water Deficit

Forage crop productivity has lately reduced in countries located in arid and semi-arid regions worldwide due to intensive consumption and the successive years of drought. This problem is exacerbated by the progress of water scarcity. Thus, the current study is aimed at improving the forage productivity and quality of clitoria as a leguminous fodder crop to be involved in crop rotations under low water supply conditions. As an attempt for facing the drought issue, a two-year (SI and SII) field experiment was conducted to evaluate the influence of irrigation pattern (IP) and plant density (PD) on clitoria morpho-physiological attributes, nutritive value, productivity, and irrigation water-use efficiency (IWUE) in two growth cycles (GCI and GCII). Based on the soil water depletion method, three irrigation patterns of 100% (IP0%, full irrigation), 80% (IP20%), and 60% (IP40%) were applied. The tested plant densities were 33 (PD33), 22 (PD22), and 17 (PD17) plants m−2. Findings revealed that IP0% × PD22 was the efficient treatment for enhancing the physio-biochemical attributes. However, in SI IP0% × PD22 statistically at par (p≥0.05) with IP0% × PD33, IP20% × PD22, and IP20% × PD17 (for chlorophyll content in GCI); IP0% × PD17 and IP20% × PD22 (for leaf relative water content in GCII); and IP0% × PD33, IP20% × PD33, and IP20% × PD22 (for cell membrane stability index in GCII). Along the two seasons, IP40% × PD33 was the potent practice for producing the highest leaf: stem ratio in both GCI (2.07 and 1.78) and GCII (1.18 and 0.96). Under IP40%, PD33 treatment recorded the greatest protein content in both GCI (24.1–27.0%) and GCII (21.7–19.5%) of SI and SII equaling PD22 in GCII (21.2–18.9%) of both seasons and PD17 in both GCI (24.0%) and GCII (21.5%) of SI and GCII (19.3%) of SII. The best aggregate protein yield for SI and SII was obtained under IP20% × PD33 interaction (1.36 and 1.40 t ha−1) without significant difference (p≥0.05) with IP0% × PD33 or IP40% × PD33 interactions. The greatest aggregate dry forage yield was observed in SI under IP0% or IP20% combined with PD33 (7.77 and 7.52 t ha−1) which did not differ significantly (p≥0.05). It could be concluded that irrigation by 80% water of full irrigation was found to be an efficient water-saving tactic coupled with adjusting the plant density of 33 plants m−2, which improved clitoria forage quantitative and qualitative properties, in addition to enhancing IWUE. Since leaf relative water content and cell membrane stability index decreased and proline increased in plant tissues under deficit water, clitoria is plant considered a moderately drought tolerant. Thus, clitoria is a promising plant could be successfully grown under arid agro-ecosystems.

Physiological effects of some engineered nanomaterials on radish (Raphanus sativus L.) intercropped with pea (Pisum sativum L.).

Intercropping leguminous plant species with non-legume crops could be an effective strategy to maintain soil fertility. Additionally, the application of nano-Zn and Fe in trace amounts can substantially improve the bioavailable fractionof Zn and Fe. We studied the effect of foliar application of some nanomaterials on the agronomic, physio-biochemical attributes under a radish/pea intercropping system. The radish and pea were sprayed with different nanomaterials (Zn-Fe nanocomposite, nZnO, and nanobiochar) at 0 and 50mg L-1 concentrations. Results indicated that the growth parameters of radish were higher in intercropping than in monocropping, while pea growth was inhibited in intercropping compared with monocropping. The shoot and root length, fresh weight, and dry matter of radish were increased by 28-50%, 60-70%, and 50-56% by intercropping than monocropping. Foliar spray of nano-materials further increased the growth traits of intercropped radish, such as shoot and root length, fresh weight, and dry matter, by 7-8%, 27-41%, and 50-60%, respectively. Similarly, pigments such as chlorophyll a, b, and carotenoids and the concentration of free amino acids, soluble sugars, flavonoids, and phenolics were differentially affected by intercropping and nanomaterials. The yield of the non-legume crop was increased by intercropping, whereas the legume crop exhibited significant growth inhibition due to competitive interactions. In conclusion, both intercropping and foliar spray of nanomaterials could be used as a combined approach to benefit plant growth and enhance the bioavailable Fe and Zn fractions of both crops.

Impact of exogenous salicylic acid and hydrogen peroxide on vitamins, essential nutrients and silymarin content of milk thistle grown at two different altitudes of balochistan under cadmium stress

Cadmium (Cd+2), a potentially toxic element, inhibits growth and development of several plant species, especially medicinal plants. However, exogenous supplementation of various hormones, compounds and signaling molecules helps to mitigate the impact of Cd+2 toxicity. Medicinal value of plants in today's era cannot be undermined. Silybum marianum (L.) Gaertn. (milk thistle) is one of most important and valuable medicinal plant; its silymarin content is widely being used to treat liver diseases. The present study was conducted during October 2019–March 2020 to analyze the potential impact of exogenous supplementation with 0.25 μM salicylic acid (SA) and 10 μM hydrogen peroxide (H2O2) priming, foliar and their combinational treatments on various attributes of milk thistle at two diverse ecological zones of Balochistan province of Pakistan, i.e., Quetta (Qta) and Turbat (Tbt) under Cd+2 toxicity. So far, no study conducted considering these two ecological zones of Pakistan with respect to cadmium toxicity on milk thistle nutritional and physio-biochemical attributes. The design of the experiment was randomized complete block design (RCBD) under factorial with three replication each treatment. Results portrayed that SA and H2O2, priming, foliar spray and combinational treatments were quite effective in alleviating the negative impacts of Cd+2 toxicity. The essential nutrients, i.e., nitrate (NO3−), calcium (Ca2+), potassium (K+) and vitamins viz., ascorbic acid (AsA), niacin and riboflavin were affected by Cd+2 induced toxicity; however, the substantial impact of SA and H2O2 helped to reduce the Cd+2 toxicity and boosted up plant nutrients vitamin content. In a nutshell, exogenous treatments of SA and H2O2 enhanced the yield potential by increasing the weight of hundred seeds, enhancing the accumulation of silymarin content in milk thistle seeds which is of prime significance for its medicinal importance in treatment of liver diseases. Therefore, the data obtained in this study highly recommends priming (P) and foliar (F) spray along with combinational treatment of SA and H2O2 as the best strategy to ameliorate Cd+2 toxicity in plants, which will ultimately lead to better growth and yield of the plants.

Elucidating the role of fly ash in root-knot nematode (Meloidogyne incognita) suppression on okra (Abelmoschus esculentus L.): Insights into cellular viability and host defence system

In the present era of climatic shift, due to many natural and anthropogenic activities, it is imperative to use eco-friendly products to improve the soil quality and production of food crops, including okra (Abelmoschus esculentus L. Moench). As chemical nematicides are damaging to the environment, there is a need for developing alternate eco-friendly measures for the management of root-knot nematodes (Meloidogyne spp.) which cause major losses to vegetable crops globally. In this regard, a pot experiment was performed under optimal environmental conditions to study the nematicidal properties of fly ash (FA) on okra. Various grades of fly ash were applied in pots containing autoclaved soil before seed sowing. Results indicated that the application of 20% FA level (80:20 w/w field soil: fly ash) was found most beneficial for soil health, improving growth and yield traits, physio-biochemical attributes, and antioxidant properties of okra by alleviating the harmful effects of root-knot nematode (Meloidogyne incognita Kofoid and White, 1919; Chitwood, 1949) compared to other treatments. Stomatal attributes of okra also improved at 20% FA level, as demonstrated by scanning electron microscopy. Galls, egg mass formation and reproduction factor of M. incognita was significantly reduced at 20% FA level. Moreover, laser confocal microscopy combined with scanning electron microscopy revealed that 20% FA application enhanced root cell viability and detoxifies the accumulation of reactive oxygen species.