Remediation of pear iron chlorosis by nanocellulose-iron chelation and mechanisms

Background: Nanocrystal cellulose has a strong ability to chelate iron and the nanocomposite possesses strong adsorptive property. Iron deficiency chlorosis (IDC) is a mineral disorder that weakens pear photosynthesis and cause a significant decline in plant yield and quality. Conventional methods to control IDC are generally due to low efficiency and overuse of chemicals. The purpose of this study was to explore the capability of nanocellulose (NC)-Fe chelate to remediate pear IDC. Acidic hydrolyzed NCs were chelated with Fe (NCFe) based on the net charge density of the components. Foliar application of NCFe was employed to pre-etiolated seedlings of Pyrus betulifolia as a plant material. The ability of NCFe to promote active iron content (CFe), photosynthesis rate, and relative gene expression was studied. Results: Nanocrystal cellulose prepared by acidic hydrolysis exhibit rod-like whiskers carrying on negative charges. When NCs were mixed with FeSO4, the NCFe particles maintained a small, whisker-like morphology with small dots (Fe) on the surface of the NC particles. The Z-average hydrodynamic diameter and zeta potential of the NC whiskers measured by DLS were 84.3 ± 0.2 nm and -47.3 ± 1.7 mV, respectively. The particle size and zeta potential of NCFe were 107.4±3.0 nm and -9.7±0.4 mV, respectively. The results showed that NCFe could significantly mitigate IDC in seedlings by increasing CFe, photosynthesis parameters, major physiological indicators, and regulating the expression of key enzymes. When NCFe was prepared at a NC-to-Fe charge density ratio of 1:3,000, CFe and chlorophyll contents were enhanced by approximately 9 times and 72.7%, respectively; the major physiological indicators were all significantly increased. Interestingly, NCFe treatment significantly downregulated the expression of the pectin methylesterase gene (PbPME) and upregulated the expression of the ferritin gene (PbFER) to increase CFe.Conclusion: NCs have strong potential to promote plant photosynthesis when chelated with Fe. The remediation capability of NCFe to IDC is attributed to the enhancement of photosynthesis parameters and indicators. NCFe treatment significantly downregulated the expression of the PME gene (PbPME) and upregulated the expression of the ferritin gene (PbFER) to increase the active iron content. This finding will provide a good alternative and a complementary strategy for Fe-chelate applications in plant iron chlorosis management.

Effect of integrated nitrogen management and foliar spray of iron on groundnut yield, quality and economics in arid region

Aim: This experiment was conducted to find out appropriate technical intervention for integrated management of nitrogen and iron chlorosis in irrigated groundnut in arid regions. Methodology: Two levels of farmyard manure, five levels of nitrogen and three levels of iron spray were applied in irrigated groundnut. Chlorophyll content, active iron content, periodic dry matter accumulation, oil content and yield, protein content and nutrient uptake by groundnut were studied. Most effective level of farmyard manure, nitrogen application and iron spray were identified for optimum management of the resources.? Results: The results showed that application of farmyard manure @ 15 t ha-1, nitrogen @ 60 kg ha-1 in two or three splits and foliar spray of FeSO4 @ 1.0 % in combination with citric acid @ 0.1% was found supportive in correcting iron chlorosis by increasing chlorophyll and active iron content, improving oil content and yield, protein content and nutrient uptake and ultimately enhancing net return by groundnut under irrigated conditions. Interpretation: Farmyard manure, higher dose of nitrogen in split application and foliar spray of iron is helpful in correcting iron chlorosis, improving growth, quality and nutrient uptake and increasing income of groundnut growers under irrigated condition in arid regions.