Photosynthetic components associated with differential senescence of maize hybrids following ear removal

T. R. Connell, F. E. Below, R. H. Hageman, M. R. Willman

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of ear removal on carbon exchange rate (CER), leaf resistance, transpiration and internal CO2 concentration of leaves for two field-grown maize (Zea mays L.) hybrids was determined using a portable photosynthesis system. Ears were removed 15 days after anthesis and measurements were made at intervals during grain development on the first leaf above the ear. Leaf CER and transpiration of earless cv. B73 × Mo17 plants were lower than controls by 4 days after ear removal (DAER) and were not detectable by 18 DAER. In contrast, ear removal from cv. FS854 plants did not affect leaf CER or transpiration relative to eared controls until 9 DAER, and leaves retained 20% of maximum CER and transpiration by 29 DAER. The decline in CER in both hybrids did not appear to be due to stomatal closure, as initial internal CO2 concentrations were sufficient to support adequate CER. The levels of CER, transpiration, and leaf resistance were consistent with visual estimates of leaf senescence. Grain harvested from the eared plants used for CER measurements showed that FS854 plants had more (23%) and heavier (4%) kernels than B73 × Mo17 plants. For FS854, the larger kernel number of comparable weight was attributed to the maintenance of a relatively higher level of leaf photosynthesis during the later stages of grain fill. The differences in CER and visual ratings indicate that the rate of leaf senescence following ear removal may be useful in identifying hybrids with late-season photosynthetic capabilities and high production potential.

Original languageEnglish (US)
Pages (from-to)55-62
Number of pages8
JournalField Crops Research
Volume17
Issue number1
DOIs
StatePublished - Sep 1987

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Soil Science

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