Drought stress introduces growth, physiological traits and ecological stoichiometry changes in two contrasting Cunninghamia lanceolata cultivars planted in continuous-plantation soils

Abstract

Background: The decrease of Cunninghamia lanceolata (Lamb.) production on continually planted soil is an essential problem. In this study, two cultivars (a normal cultivar, NC, and a super cultivar, SC) with two-year-old seedlings were grown in two types of soil (non-planting of Chinese fir, NP soil; continuous planting of Chinese fir, CP soil) with three watering regimes, and the interaction effects on plant growth and physiological traits were investigated. Results: The water contents of normal water control (CK), medium water content (MWC) and low water content (LWC) soil reached 75%-80%, 45%-50% and 20%-25%, respectively, of the field water capacity. The results indicated that both CP soil and LWC soil had negative effects on growth and physiological traits. In both cultivars, CP soil significantly decreased plant growth and the performance of physiological traits. The LWC soil changed the ecological stoichiometry in the three organs, induced oxidative stress, promoted water use efficiency and damaged chloroplast ultrastructure. Compared with NC, the SC cultivar was more tolerant to CP soil and drought stress. Conclusions: The CP soil shows negative effect on C. lanceolata’s physiological traits, and these effects can be exacerbated by drought stress. Therefore, the utilization of continuous planted soil can cultivate improved varieties of C. lanceolata and maintain water capacity. This can improve their growth and physiological performance to a certain extent.