Enhanced plant growth promoting role of phycomolecules coated zinc oxide nanoparticles with P supplementation in cotton (Gossypium hirsutum L.)

This report focuses on application of zinc oxide nanoparticles (ZnONPs) carrying phycomolecule ligands as a novel plant growth promoter aimed at increasing the crop productivity. The present investigation examined the effect of ZnONPs on plant growth characteristics, and associated biochemical changes in cotton (Gossypium hirsutum L.) following growth in a range of concentrations (25-200 mg L^-l ZnONPs) in combination with 100 mM P in a hydroponic system. Treated plants registered an increase in growth and total biomass by 130.6% and 131%, respectively, over control. Results demonstrated a significant increase in the level of chlorophyll a (141.6%), b (134.7%), carotenoids (138.6%), and total soluble protein contents (179.4%); at the same time, a significant reduction (68%) in the level of malondialdehyde (MDA) in leaves with respect to control. Interestingly, a significant increase in superoxide dismutase (SOD, 264.2%), and peroxidase (POX, 182.8%) enzyme activities followed by a decrease in the catalase (CAT) activity, in response to above treatments. These results suggest that bioengineered ZnONPs interact with meristematic cells triggering biochemical pathways conducive to an accumulation of biomass. Further investigations will map out the mode of action involved in growth promotion.

Dietary supplementation of green synthesized manganese-oxide nanoparticles and its effect on growth performance, muscle composition and digestive enzyme activities of the giant freshwater prawn Macrobrachium rosenbergii

The green synthesized Mn3O4 nanoparticles (manganese-oxide nanoparticles) using Ananas comosus (L.) peel extract was characterized by various techniques. HR-SEM photograph showed that manganese-oxide nanoparticles (Mn-oxide NPs) were spherical in shape, with an average size of 40-50 nm. The Zeta potential revealed the surface charge of Mn-oxide NPs to be negative. Further, the Mn-oxide NPs were dietary supplemented for freshwater prawn Macrobrachium rosenbergii. The experimental basal diets were supplemented with Mn-oxide NPs at the rates of 0 (control), 3.0, 6.0, 9.0, 12, 15 and 18 mg/kg dry feed weight. The as-supplemented Mn-oxide NPs were fed in M. rosenbergii for a period of 90 days. The experimental study demonstrated that prawns fed with diet supplemented with 3-18 mg Mn-oxide NPs/kg shows enhanced (P<0.05) growth performance, including final weight and weight gain (WG). Significant differences (P<0.05) in feed conversion ratio (FCR) were observed in prawn fed with different diets. Additionally, prawns fed with 3.0-18 mg/kg Mn-oxide NPs supplemented diets achieved significant (P<0.05) improvement in growth performance, digestive enzyme activities and muscle biochemical compositions, while, the prawns fed with 16 mg/kg of Mn-oxide NPs showed enhanced performance. Prawns fed on diet supplemented with 16 mg/kg Mn-oxide NPs showed significantly (P<0.05) higher total protein level. The antioxidants enzymatic activity (SOD and CAT) metabolic enzymes status in muscle and hepatopancreas showed no significant (P>0.05) alterations in prawns fed with 3.0-18 mg/kg of Mn-oxide NPs supplemented diets. Consequently, the present work proposed that 16 mg/kg of Mn-oxide NPs could be supplemented for flexible enhanced survival, growth and production of M. rosenbergii. Therefore, the data of the present study recommend the addition of 16 mg/kg of Mn-oxide NPs diet to developed prawn growth and antioxidant defense system.

Arbuscular mycorrhizal fungi alleviate oxidative stress induced by ADOR and enhance antioxidant responses of tomato plants

The behaviour of tomato plants inoculated with arbuscular mycorrhizal (AM) fungi grown in the presence of aqueous extracts from dry olive residue (ADOR) was studied in order to understand how this symbiotic relationship helps plants to cope with oxidative stress caused by ADOR. The influence of AM symbiosis on plant growth and other physiological parameters was also studied. Tomato plants were inoculated with the AM fungus Funneliformis mosseae and were grown in the presence of ADOR bioremediated and non-bioremediated by Coriolopsis floccosa and Penicillium chrysogenum-10. The antioxidant response as well as parameters of oxidative damage were examined in roots and leaves. The data showed a significant increase in the biomass of AM plant growth in the presence of ADOR, regardless of whether it was bioremediated. The establishment and development of the symbiosis were negatively affected after plants were exposed to ADOR. No differences were observed in the relative water content (RWC) or PS II efficiency between non-AM and AM plants. The increase in the enzymatic activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione-S-transferase (GST; EC 2.5.1.18) were simultaneous to the reduction of MDA levels and H2O2 content in AM root growth in the presence of ADOR. Similar H2O2 levels were observed among non-AM and AM plants, although only AM plants showed reduced lipid peroxidation content, probably due to the involvement of antioxidant enzymes. The results highlight how the application of both bioremediated ADOR and AM fungi can alleviate the oxidative stress conditions, improving the growth and development of tomato plants.