Abstract: By using SPAD-502 chlorophyll meter, LI-6400 portable photosynthesis system, and spectrophotometer, the leaf SPAD value, net photosynthetic rate ( Pn), and chlorophyll (a+b) content (Ct) of 3-year-old Machilus pauhoi and M. leptophylla seedlings were measured, and the relationships of SPAD value with Pn and Ct were analyzed. The M. pauhoi seedlings were grown from the seeds originated from Suichuan County of Jiangxi Province and Ji an’ou County of Fujian Province, named as MPS and MPJ, respectively; while the M. leptophylla seedlings were grown from the seeds originated from Shangyou County of Jiangxi Province, named as MLG. There were significant differences in the mean chlorophyll content of MPS, MPJ, and MLG. The SPAD value and the conten ts of chlorophyll (a+b) (Ct), chlorophyll a (Ca) and chlorophyll b (Cb) we re in the order of MPS<MLG<MPJ, with the mean SPAD value being 4380, 4512, and 5067 and the Ct value being 1944, 2831, and 3447 mg·g-1 , respectively. The chlorophyll content was influenced by the maturing degree of meso phyll tissues of M. pauhoi and M. leptophylla, being lower in current-year le aves than in 2-year-old leaves. The Ct of same age leaves at different c rown layers of MPS and MPJ and of MLG was in the order of upper layer<middle la yer<lower layer and of upper layer<lower layer<middle layer, respectiv ely, and the SPAD value of the same lamina at different positions was in the ord er of apex<middle<base. SPAD value had a significant positive linear correla tion with Ct, and a statistically not significant positive correlation wit h Pn.

Key words: climate change, spatiotemporal distribution, accumulated temperature, planting pattern, rice.