Growth and water use of Lolium perenne. 2. Plant growth.
The effects of decreasing water potential of the soil and plant on growth of L. perenne were studied. Leaf and root extension growth decreased by 50% when plant-water potential decreased from -3 to -6 bar, and growth stopped at -16 bar. DM accumulation and leaf area also decreased because of slower expansion growth and senescence of the older leaves. Growth could not be related to water potential with accuracy because of the rapid changes of soil-and plant-water potential, but a small decrease in soil-water potential had a large effect on growth because of the more rapid decrease in plant-water potential due to a large plant resistance. The importance of turgor in growth is considered, and the causes of increased plant resistance and decreased growth are briefly discussed.