Leakage of inorganic compounds from artificially-aged radish (Raphanus sativus L.) and Chinese cabbage (Brassica rapa ssp. pekinensis) seeds and use of phosphate leakage from single seed as a tool for assessing viability

Abstract

Inorganic compounds, Ca, Mg, P, Na, K, B, Mo, Mn, Cu, Fe and Zn, in the seed leachate of artificiallyaged (AA) seeds from three cultivars of radish (Raphanus sativus L.) and Chinese cabbage (Brassica rapa ssp. pekinensis) seeds were measured and compared to those of non-aged (NA) seeds, and a technique to detect phosphate leakage from the leachate from single seeds was developed as a tool for assessing viability. K leached out in much greater quantities than other elements in both NA and AA seeds, followed by P, Na, Ca, Mg, and B in the AA seeds. The Mn and Cu were not detected in any cultivars, while Mo and Fe in Chinese cabbage seeds and Zn in radish seeds were only present in trace amounts of leachate from AA seeds. In general, K, P, Na, Ca, Mg, and B leakage occurred in large amounts from AA seeds relative to NA seeds, though there were different ratios of AA to NA seeds. Evaluation of the ratio of AA to NA seeds of inorganic compound leakage revealed that P was greatest, followed by Mg, K, Na and Ca. A spectrophotometric determination of phosphate from single seed leachate was developed using multi-plate reader. This technique is simple, fast, nondestructive and inexpensive, and applicable to many individual seeds at one time. The relationships between percent germination and absorbance (630 nm) of the single seed leachate with phosphate leakage from Chinese cabbage and radish seeds that had been artificially aged to give various viability levels appeared to have very high negative correlations. In conclusion, phosphate detection from single seed leakage could provide a valuable and practical tool for assessing seed viability.