Root growth in Siberian larch (Larix Sibirica Ledeb.) seedlings seasonal variations and effects of various growing regimes, prolonged cold storage and soil temperatures

Abstract

Root growth in Siberian larch (Larix sibirica Ledeb.) seedlings was studied to identify seasonal variations during two growing seasons. The results demonstrated distance variations in root growth capacity. During the first growing season, root growth peaked in the middle of September, after which root growth declined rapidly to a very low level only three weeks later. During winter, root growth capacity was low followed by a rapid increase in early May. Various growing regimes to induce dormancy, such as changes in photoperiod and night temperature during early fall, affected root growth capacity dramatically, with very low values for seedlings grown under long and/or cold night treatments. Prolonged cold storage at -4°C had a negative effect on root growth in Siberian larch seedlings. Root growth capacity was significantly higher for seedlings stored from November to mid-March compared with seedlings stored until mid-May. Root growth was also studied at different soil temperatures, ranging from 5 to 30°C. Maximum root growth capacity was registered at 25°C. Reasons for this result and others mentioned above are discussed in the paper.