Chemical root pruning improves quality and nutrient uptake of Cape Gooseberry (Physalis peruviana) seedlings

Abstract

Cape gooseberry is an annual crop in temperate regions, and it is yearly planted in seed trays for initial development, and outplanted to the field for fruit production. Although, a matted and spiraled root morphology, as a consequence of seed trays/containers, may negatively interfere the outplanted seedling performance due to such impaired attributes. Thus, the objective of this study was: (1) to determine the effect of chemical root pruning on quality of cape gooseberry seedlings (2) to determine whether copper hydroxide or copper oxide, and the appropriate rates that are the most effective to enhance seedling quality. To do so, the cells of seed trays were painted internally with a mix of latex ink and copper hydroxide or copper oxide at the rates of 0, 12, 24, 36, and 48 g.L−1 of Cu (equivalent of metallic copper), for the seedlings of cape gooseberry to grow throughout 87 and 105 days after sowing (DAS). Both copper compounds promoted root pruning accordingly to the rate. For the seedlings grown throughout 87 days in the seed trays, the effect of root pruning intensity caused by copper hydroxide induced the seedlings to have a balanced shoot growth, an improved root system morphology, and a better nutritional status that was achieved with the concentration of 24 g.L-1 of Cu. The same was found for the seedlings grown throughout 105 days in the seed trays, with copper hydroxide at the concentration of 48 g.L-1 of Cu. These results suggest that chemical root pruning of seedlings using copper hydroxide improves root morphology and increases the nutrient uptake capacity.