Abstract: Effects of different water conditions on proline and chlorophyll contents in current-needles and previous-needles of Pinus koraiensis and P. sibirica were studied. Three-year-old potted P. koraiensis and P. sibirica were taken as materials with four water regimes: 29％～31％（C）, 22%～24%（L）, 15%～17%（M） and waterlogging condition（W）. The results were as follows: 1) proline content varied with leaf age and species. Chlorophyll content of current-needles was higher than that of previous-needles in P. koraiensis, and it was opposite in P. sibirica. Proline content in P. koraiensis was generally higher than that in P. sibirica; 2) proline content was accumulated significantly in both two species under waterlogging. Water stress appeared after one month treatment in P. koraiensis, and this was earlier than in P. sibirica. The previous-needles of both two species was under water stress as the soil water contents reached 15%～17%, but the effect in P. koraiensis was larger than in P. sibirica. 3) The accumulation of chlorophyll content had little correlation with the capacity of resistance to water stress in the two species; 4)P. sibirica had wider water fitting range than P. koraiensis; the capacity of resistance to water stress in current-needles was bigger than that in previous-needles in both two species.

Key words: Pinus koraiensis Sieb.et Zucc., P. sibirica(Loud).Magr., chlorophyll, proline, water stress