Effect of Water Stress and Clipping on Photosynthate Translocation in two Grasses1
- Ronald E. Sosebee and
- Herman H. Wiebe2
Photosynthate translocation in crested wheatgrass (Agropyron cristatum (L.) Gaertn.) and cultivated barley (Hordeum vulgare (L.) cultivar ‘Hiland’) was studied under controlled environments. Treatments consisted of two levels of internal water stress (soil at field capacity cir withheld for 4 to 7 days before isotope application) and three levels of defoliation (none, entire plant clipped to 10 to 15-cm stubble height except for one tagged leaf, or entire plant clipped to 10 to 15-cm stubble height except for one tagged leaf with the tip removed 8 to 10 cm from the collar.) Radiophosphorus applied to a photosynthetically active leaf was used to trace translocation to various plant parts.
Increased water stress decreased the total amount translocated from the mature leaf in both species. In barley, the water stress became more severe, and translocation beyond the sheath of the tagged leaf was negligible. Partial defoliation increased the translocation from tie tagged leaf to other plant parts, especially in plants grown without adequate water. Reduced water consistently increased the proportion of radiophosphorus translocated downward to the roots and crowns, while partial defoliation consistently increased the proportion transported to the younger leaves.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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