effect of foliar application of nano and micro iron oxide particles with d.g adjuvant and rcp-5 additive material on some physiological traits of green bean (phaseolus vulgaris l.)

introduction iron (fe) has a crucial biological role in human and plant growth. this micronutrient is a major player in chloroplast photosynthesis and enzymes. although some enzymes, such as fe-dependent superoxide dismutase, use molecular fe as a cofactor directly, most proteins use fe-containing factors. various studies were carried out to understand the effect of nanoparticles on the growth of plants. nano-particles have high reactivity because of the more specific surface area, more density of reactive areas, or increased reactivity of these areas on the particle surfaces. sheykhbaglou et al. (2012) showed that application of nano-iron oxide particles increased soybean growth and yield than micro iron particles. iron deficiency can be corrected by foliar application of iron more efficiently than the soil application of iron sources. to achieve maximum nutrient absorption via foliar applications, a fine mist application with spreading and wetting agents is desired. these agents provide quick wetting of plant tissue and more uniform coverage and as a result more absorption of solutions. therefore, the objective of this study was to investigate the effect of foliar application of nano and micro iron oxide particles with additive material on some physiological traits of green bean (phaseolus vulgaris l.). materials and methods this study was arranged as factorial based on randomized complete block design with three replications to investigate the effects of fe nano particles (np) and micro particles (mp) foliar application with additive material on some physiological traits of green bean at the faculty of agriculture, shahrood university of technology in 2012. geographically, the site is located in bastam (36° 29’e, 55° 57’n, 1366 m a.s.l.). the climate of this region is semi-arid. the first factor was foliar application of fe in five levels (0, 0.25, and 0.5 g l−1; in two forms: np and mp) and the second factor was additive materials in three levels (0, d.g adjuvant and rcp-5). the foliar application was performed 55 days after sowing in the beginning of flowering stage. at harvest, the plant characteristics namely leaf area index, height, pod and leaf iron, chlorophyll, carotenoid and protein were also registered. statistical analyses of data were performed with statistical software mstat-c. significant differences between means refer to the probability level of 0.05 by lsd test. results and discussion results showed that leaf area index was not affected by treatments. the highest fe level in leaves (311 mg kg-1) and in pods (51.47 mg kg-1) was obtained by application of 0.25 g l-1 fe mp + d.g adjuvant (figures 2 and 3). bybordi & mamedov (2010) reported that with spraying of fe the highest amount of fe accumulation was obtained in canola leaf. rcp-5+0.5 g l-1 fe np treatment showed the highest pod protein content. monsef afshar et al., (2012) represented that foliar application of fe increased protein percentage of leaf compared to the other treatments. micro-nutrients such as fe and zinc participate in the structure of proteins and also in nitrogen metabolism and thereby may also cause to increase the protein amount. uhlig & wissemeier (2000) recorded an increased cuticular penetration of calcium containing surfactants. leaf and stem tissues can inhibit initial nutrient absorption by means of waxy substances in the cuticle. thus, it seems that d.g adjuvant and rcp-5 have improved the effects of fe on plant characteristics through increasing absorption of iron especially in low concentrations. similar to our results singh et al., (1990) reported that application of iron sulphate and iron pyrite decreased chlorosis and increased chlorophyll and carotenoid contents of groundnut leaves significantly. conclusion based on the results of the present study, using additive materials such as d.g adjuvant and rcp-5 can enhance the effects of iron as nano and micro particles on chlorophyll contents and pod protein of green bean through providing quick wetting of plant tissue and more uniform coverage with increased spray retention by reducing the surface tension of the spray droplets.