Effects of shade and rain-sheltered cultivation on peony growth, development and flowering quality

Climate warming will lead to an increased frequency of extreme summer heat and uneven rainfall distributions, both of which seriously affect the production and quality of ornamental peonies in the field. We explored the effects of different shade intensities (full light, 20% light, and 40% light) and rain-sheltered cultivation methods on the growth, physiological parameters, and bloom quality of peony plants. The findings revealed that either rain-sheltered cultivation or shade cultivation, as well as their combination, promoted peony growth and development. The effect of shade on the plants after rain-sheltering treatment depended on the shade intensity, and 40% light was better than 20% light or full light. This occurred because 40% light caused plants to accumulate more chlorophyll and carotenoids, reduced the accumulation of MDA, and increased the soluble sugar content, proline content and CAT activity. The main findings of this study demonstrated that rain-sheltered or shaded cultivation combined with these treatments had positive effects on peony nutrient growth and bloom quality and that the rain-sheltering + 40% light treatment had the greatest effect on the growth of peony plants. The results provide a theoretical basis for optimizing peony field growth conditions and promoting high-temperature cultivation in the summer.