Irrigation-Induced Changes in Chemical Composition and Quality of Seeds of Yellow Lupine (Lupinus luteus L.).

The quality and amount of yellow lupine yield depend on water availability. Water scarcity negatively affects germination, flowering, and pod formation, and thus introduction of an artificial irrigation system is needed. The aim of this study was to evaluate the influence of irrigation on the quality of yellow lupine seeds. Raining was applied with a semi-solid device with sprinklers during periods of greatest water demand. It was shown that watered plants produced seeds of lesser quality, having smaller size and weight. To find out why seeds of irrigated plants were of poor quality, interdisciplinary research at the cellular level was carried out. DNA cytophotometry evidenced the presence of nuclei with lower polyploidy in the apical zone of mature seeds. This may lead to formation of smaller cells and reduce depositing of storage materials. The electrophoretic and Fourier transform infrared spectroscopic analyses revealed differences in protein and cuticular wax profiles, while scanning electron microscopy and energy dispersive spectroscopy revealed, among various chemical elements, decreased calcium content in one of seed zones (near plumule). Seeds from irrigated plants showed slightly higher germination dynamics but growth rate of seedlings was slightly lower. The studies showed that irrigation of lupine affected seed features and their chemical composition, an ability to germination and seedlings growth.

Irrigation affects characteristics of narrow-leaved lupin (Lupinus angustifolius L.) seeds.

MAIN CONCLUSION: While plant irrigation usually increases yield, irrigation also affects seed characteristics with respect to endoreplication level, chemical composition, number of carbonyl bands, and cuticular wax profiles. Seeds of sweet varieties of the narrow-leaved lupin have good nutritional properties; however, these plants are sensitive to water deficit. Irrigation improves lupin yield, but can affect seed characteristics. The purpose of the study was to evaluate irrigation influence on lupin seed features and their chemical composition. Morphological analyses showed worse quality of seeds from the irrigated plants, with regard to their size and weight. This was confirmed by cytophotometric analyses which revealed a lower DNA content in the nuclei of cells from the apical and basal regions of the irrigated seeds. The lower degree of polyploidy of the nuclei entails lower cell sizes and limited space for storage components. Fourier transform infrared spectroscopic analysis demonstrated that protein and cuticular wax profiles of the irrigated seeds were different from the control. The electrophoretic analyses indicated differences in protein profiles including changes in the proportion of lupin storage proteins. Among the various studied elements, only the nitrogen content decreased in the embryo axis of irrigated plants. Although germination dynamics of the irrigated seeds was higher, the seedlings' development rate was slightly lower than in the control. The hydrogen peroxide level in root meristem cells was higher during germination in the control suggesting its regulatory role in seed metabolism/signaling. Our study indicated that irrigation of lupin plant affected seed features and composition.