Abstract
Cadmium pollution is severe in cucumber, although grafting is an effective method to improve its stress tolerance. Pumpkin is the commonly-used grafting rootstock for cucumber, and the breeding of rootstock with cadmium tolerance plays a vital role in the safe production of cucumber. However, there are no reports on rootstocks specific for cadmium tolerance. In this study, the rootstock of a pumpkin cross combination and its parents were used for the study of cadmium stress. The results indicated that under the 24mg·L− 1cadmium stress, the relative conductivity of cross combination decreased by 35.86%~36.31% compared with the parents. When the concentrations of cadmium stress were 8 mg·L− 1and 16 mg·L− 1, respectively, the peroxidase (POD) activity of cross combination was higher than those of the parents. The subcellular distribution of cadmium in the root systems of the cross and the 041 − 1 parent was in the cell wall first, followed by the cytoplasm and organelle, while that in the root system of 360-3 parent was in the cell wall first, followed by the organelle and cytoplasm. Under cadmium stress with the 24mg·L− 1concentration, the transfer coefficient of cross was significantly lower than that of the parents. The cross initiated the activity of membrane protective enzyme POD under cadmium stress, relieved the damage to membrane, and reduced the toxicity of cadmium through the accumulation of cadmium in the cell wall that blocked its entrance to the cytoplasm. This study provides a theoretical foundation to breed cadmium-tolerant rootstocks for melon vegetables.
Anatomical and ultrastructural alterations in Ceratopteris pteridoides under cadmium stress: A mechanism of cadmium tolerance
