PJB-2017-589
Leaf physiological and anatomical characteristics of two indicator species in the limestone region of southern China under drought stress
Yongbin Wu
Abstract
Drought is a critical limiting factor of plant growth, and plants living in arid areas are required to develop adaptation mechanisms to resist drought stress. In this study, we evaluated the drought resistance mechanisms of two tree species of Triadica rotundifolia and Cinnamomum burmannii, which are indicator plants in the limestone region of southern China based on foliar physiological and anatomical characteristics. We evaluated changes in the contents of chlorophyll, suluble protein, solube sugars, proline, malondialdehyde (MDA), proline, activity of superoxide dismutase (SOD) and peroxidase (POD), chlorophyll fluorescence parameters, and leaf anatomical structure. The results showed that, (1) The content of Chla+b, suluble protein, solube sugar and SOD activity of two species seedlings had a trend of increase at first then decrease over the entire drought experiment. The change of MDA content was more sensitive in T. rotundifolia and the peak (33.05 mmol�ml-1) appeared at the 28th day of the drought experiment. Comparatively, the proline content and POD activity were more sensitive in C. burmannii and the proline peak (217.11 ?g�g-1) appeared at the 24th day; (2) under the continuous drought stress, the electron transport rate of the seedlings decreased, whereas the non-photochemical quenching showed different trends for different species. Severe drought stress in T. rotundifolia caused an increasing trend in the light energy capture efficiency (Fv/Fm), while continuously declined in C. burmannii; (3) under the drought stress, the leaves of T. rotundifolia become thicken. Arrangement of spongy tissues became loose and the ratio of palisade to spongy was decreased. However, the leaves of C. burmannii showed a few different features: inconspicuous differentiation between palisade and spongy tissue, high loose degree of leaves, and low packing; (4) the leaf physiological indices had a strong relationship with anatomy characteristics, as revealed by principal component analysis (PCA), strong adaptability to drought tolerance of T. rotundifolia higher than C. burmannii. All the results suggest that T. rotundifolia is better to adapt to drought conditions due to its physiological and anatomical characteristics, allowing the species to better buffer drought-induced physiological responses and variability in leaf structure.
To Cite this article:
Download
