Green Needlegrass Seedling Morphology in Relation to Planting Depth

Abstract

Green needlegrass (Stipa viridula Trin.) is commonly used in range seedings and revegetation of disturbed lands in the northern Great Plains. This study was conducted to determine the influence of planting depth, seed source, and temperature on morphology and emergence of green needlegrass seedlings. Seeds from 2 sources were planted at depths of 1.5, 3.0, 4.5, 6.0, and 7.5 cm in pots filled with sandy loam soil. Pots were placed in growth chambers adjusted for either a 20/15 degrees C (15 h light/9 h dark) temperature regime or a 25/20 degrees C regime. Coleoptile length increased with planting depth, while seminal primary root length, adventitious root length, and number of adventitious roots decreased with planting depth. 'SD-93' seedlings had shorter subcoleoptile internodes, longer coleoptiles, and better root development than 'Lodorm' seedlings. Seedlings grown under the warmer temperature regime had better root development than seedlings grown under the cooler regime, but reach of the coleoptile above planting depth was not as great. Results indicated that green needlegrass generally should not be planted at depths greater than 3.0 cm because of lower percent emergence, rate of emergence, and poor root development when seedlings emerged from greater depths.