Moderate Nitrogen Deposition Alleviates Drought Stress of Bretschneidera sinensis

Droughts are becoming more frequent and intense, the nitrogen deposition rate is increasing worldwide due to human activities. Young seedlings of Bretschneidera sinensis Hemsl. susceptible mortality under drought conditions because their root tips have few hairs. We studied effect on physiological characteristics two-year-old B. stress. Seedlings were grown no (control; N0), low (N30, 30 kg·hm−2 year−1), medium (N60, 60 high (N90, 90 subjected either normal watering regime (NW) or stress (DW). Under DW, relative conductivity (RC) receiving N60 was not significantly different from that N0 seedlings, RC N90 higher than seedlings. 10 d treatment increased antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activities content soluble protein, chlorophyll a + b, with POD activity protein by 18.89% 34.66%, respectively. proline (PRO) treated increased. Our data suggested moderate could alleviate decreasing cell membrane permeability, reducing peroxidation, osmoregulatory substances, tendency for decline, whereas sensitivity aggravated degree stress, thereby affecting growth.