MORPHOLOGICAL DEVELOPMENT AND ANATOMICAL FEATURES OF WHEAT SEEDLINGS AS INFLUENCED BY TEMPERATURE AND SEEDING DEPTH

Temperature and seeding depth are two major factors influencing the early development of winter wheat (Triticum aestivum L.). The morphological and anatomical features were investigated for plants grown at seeding depths of 3, 6, and 9 cm and ambient temperatures of 10, 20, and 30 degrees C to determine the effects planting depth and temperature had on certain seedling properties important in seedling physiology. Planting at 6- and 9-cm depths and at 10 degrees C significantly reduced seedling emergence rate, shoot and root dry weight, leaf area, and number of seminal and crown roots. Deep planting limited seminal root number to about three and increased subcrown internode length in all temperature regimes. Planting at 9-cm depth and at 30 degrees C near surface temperature reduced effective xylem radius in the subcrown internode. It was concluded that the decreased seedling growth and xylem radius of the subcrown internode and associated hydraulic properties by deep planting depended strongly on the growing condition temperature, and was minimized at the optimal temperature (20 degrees C) for early development of wheat seedlings. Planting at a deeper depth and higher temperature has the potential of increasing hydraulic resistance of the subcrown internode for wheat seedlings.