| 【Objective】The study was conducted to explore the physiological and biochemical response mechanism
of Thunbergia Laurifolia mature seedlings to drought.【Method】The mature seedlings of T. Laurifolia were selected as the
materials, and the pot water control method was adopted. Three water treatments were set, namely, normal water supply（CK）,
moderate drought stress（MD）and severe drought stress（SD）. The morphological index, photosynthetic index and
chloroplast ultrastructure were determined.【Result】Compared with the control, the morphological indexes such as plant
height, ground diameter, number of leaves, leaf length, leaf width and root-top ratio of each treatment all decreased gradually
with the aggravation of drought. The diurnal variation of net photosynthetic rate of T. Laurifolia under all treatments had
the phenomenon of photosynthesis "napping". Compared with the control, the water use efficiency were higher under MD
and SD treatments（0.89 µmol/mmol and 0.77 µmol/mmol, respectively）. The chloroplast ultrastructure changed greatly
under MD and SD treatments. 【Conclusion】The mature seedlings of T. Laurifolia could respond to harsh environmental
drought conditions by reducing photosynthesis, closing stomata and improving water use efficiency. The chloroplast structure
of T. Laurifolia changed under the MD treatment. Although the chloroplast structure was seriously damaged under the SD
treatment, no death was observed in the mature seedlings, indicating that the mature seedlings of T. Laurifolia had strong drought tolerance. T. Laurifolia can be applied in landscape because it is more resistant to drought. |
