New Method for Supplying Substances to Cereal Inflorescences
- B. L. Ma and
- Donald L. Smith
Study of nutritional and metabolic requirements of developing grain in cereal crops is hampered by the lack of methods for supplying substances directly to the spike during a substantial portion of the grain-fill period. The objective of this study was to develop a system for continuous feeding of solutions containing nutrients or metabolic effectors into the peduncle of barley (Hordeum vulgare L. cv. Leger) plants and to observe their effects on the quantity and quality of the resulting grain. For each plant, one needle was inserted into the peduncle near the bottom and a second near the top. These were sealed to the peduncle with latex and attached to 20-cm lengths of flexible plastic tubing. The tubing on the lower needle was attached to a syringe barrel. Both the syringe barrel and the open end of the upper tube were held above the spike. Solutions were placed in the syringe barrel and these flowed through the peduncle and into the upper tube. The plants were allowed to draw KNO3 or urea (30 mM-N) solutions from this system for 20 d. The volume of solution taken up ranged from 37 to 68 mL. Supplying these N sources with the peduncle perfusion system increased N concentrations in barley grain by up to 40% and total grain N per spike by 25% relative to nonperfused or distilled water perfused controls. The amount of N removed from the perfusion system was equal to ≈50% of the total grain N per spike. Use of the perfusion system was not disruptive to normal spike development. These results show that this peduncle perfusion system is capable of delivering large quantities of substances to the developing grain of hollow-stemmed grasses.
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