Changes in protein profiles of poplar tissues during the induction of bud dormancy by short-day photoperiods

Vegetative bud dormancy in woody perennial plants of the temperate regions is an important adaptive strategy for withstanding low winter temperatures. We used short-day (SD) photoperiods to induce bud dormancy in poplar (Popu lus deltoides Bartr. ex Marsh.), and characterized changes in protein profi les during dormancy development. Short days alone, under warm temperatures (25 degrees C) induced a high level of dormancy comparable to that develope d naturally. Under SD conditions the amounts of acetone/trichloroacetic aci d (TCA)-insoluble dry powder (DP) increased in terminal and lateral buds, l eaves and bark tissues. The total protein content in DP from buds and leave s steadily decreased while total protein from bark increased. The a-dimensi onal (2-D) PAGE analyses showed that terminal and lateral buds responded si milarly to SD. Four polypeptides that newly appeared or increased in abunda nce and five that disappeared or diminished in terminal buds during 10 week s of treatment were also detected in lateral buds. Two of these newly appar ent polypeptides were also found in bark. Similar polypeptides were not fou nd in leaves. Changes in protein metabolism and possibly altered gene expre ssion might be important part in the overall response of poplar to SD durin g dormancy development.