• Can Cotton (Cossypium hirsutum) Seed Vigor Be Assessed in the Absence of Growth?

      Lehle, F. R.; Zegeer, A. M.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Although seed vigor is ultimately expressed in terms of growth, it is not clear if metabolic processes unlinked to growth can also estimate vigor. The objective of this study was to determine if the relationship between seed vigor and ethanol metabolism differed depending on whether seed growth was presence or absence. For individua1 imbibed cotton seed, ethanol assimilation in air and ethanol biosynthesis in N₂ gas was correlated to seed vigor as measured by cool test performance. Seed growth in N₂ gas was prevented by the addition of polyethylene glycol. Results were inconclusive, because seed performance (radicle growth) during cool testing was not significantly correlated to either ethanol biosynthesis or ethanol assimilation. It was concluded that ethanol metabolism both in the absence and presence of seed growth has limited usefulness as a metabolic marker of cotton seed vigor.
    • Effects of Oxygen Stress and Water Stress on Cotton (Gossypium hirsutum) Seed Growth

      Lehle, F. R.; Zegeer, A. M.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The effects of oxygen stress and water stress on cotton seed radicle growth was studied. High vigor Deltapine 90 seed were imbibed in individual test tubes at 28°C for 28 hours. Seed were then subjected for 2 hours at 28°C to either 1) oxygen stress imposed by N₂ gas, 2) water stress imposed by polyethylene glycol 6000 (0.8 gm mL water⁻¹), or 3) a combination of both 1) and 2). Following imposition of either oxygen stress or water stress, radicle growth stopped temporarily; growth resumed while either stress was still imposed but at a greatly reduced rate relative to the unstressed control. Cotton radicle growth was prevented however, in the presence of both oxygen and water stress. The prevention of growth was reversible, as growth resumed when both stresses were relieved.