Effect of soil nutrition and water content on the seedling growth and physiological characteristics of Euryodendron excelsum H. T. Chang

With the pots experiments，four soil nutrition levels were designed in the experiment，such as red soil：humus= 1∶0（ST1），red soil：humus=3∶1（ST2），red soil：humus=1∶1（ST3）and red soil：humus=1∶3 （ST4）. Four soil water levels including control（W1），light water stress（W2），moderate water stress（W3），and severe water stress（W4）were designed to elucidate the effects of different soil nutrition and water content on seedling growth and its physiological characteristics of an endangered plant Euryodendron excelsum H. T. Chang. The results showed that soil nutrition and water content had significant effects on the content of soluble sugar，malondialdehyde， and proline of seedlings. The photosynthetic pigments contents such as chlorophyll a，chlorophyll b，chlorophyll a+b and carotenoid decreased with the decrease of the water and nutrition content in the soil. Seedling biomass increased with the increase of soil nutrition and reached its maximum in ST3，and then decreased in ST4. The leaf water content and relative water content also significantly decreased with decreasing soil water content. However，the leaf water saturated deficit and tissue density showed a contrary tendency