Effects of Temporary Dehydration on Growth of Green Needlegrass (Stipa viridula Trin.) Seedlings

Abstract

Green needlegrass (Stipa viridula Trin.) has been variously rated as "extremely" to "fairly" drought tolerant. This study was conducted to determine the capacity of green needlegrass seedlings for emergence and root growth following temporary dehydration. Germinating seeds were exposed to dehydration treatments of 0, -4, -10, -22, and -37 megapascals (MPa) and then planted in soil-filled pots for a 10-day growth performance test. Exposure of germinating seeds to temporary dehydration treatments of -10 MPa and lower reduced subsequent seedling emergence. When the seminal primary root of germinating seeds was excised or injured by dehydration, seedlings developed up to 3 seminal lateral roots. No additional seminal roots were developed if the seminal primary root was undamaged. Germinating seeds of green needlegrass have relatively low tolerance to dehydration possibly as a result of a low latent potential for development of seminal lateral roots and low tolerance of the embryo and developing tissues to dehydration. Sites to be seeded and planting dates should be selected so as to insure adequate soil moisture for seedling development.