Relationship between Coleoptile Elongation and Alcoholic Fermentation in Rice Exposed to Anoxia. I. Importance of Treatment Conditions and Different Tissues uri icon

abstract

  • Analysis of different tissues was important in evaluating growth and metabolism of coleoptiles. Although the coleoptile only accounted for 0.7 % of seed dry weight at 3 d after anoxia, it contained 21 % of the ethanol produced by rice seeds. There were also three-fold higher rates of R(E) on a fresh weight basis in expanding tissues in the base of the coleoptile relative to the elongated tissues at the apex. Results are discussed in terms of the importance of environmental conditions used to impose anoxia, quantification of R(E) in specific tissues and the possibility that under stagnant conditions high ethanol concentrations in tissues may limit R(E) and coleoptile growth.
  • Ethanol concentrations in coleoptiles and intact seeds (cv. IR42) were approximately 300 and 100 mol m(-3) respectively when seeds were grown 3 d in stagnant agar, however 92 % of the ethanol in seeds diffused into the external medium when solutions were mixed for 5-10 s. Coleoptile growth under anoxia was related to rates of ethanol synthesis (R(E)) in different treatments; there was greater coleoptile growth and R(E) for seeds in N-2 flushed solutions than in stagnant deoxygenated agar. Coleoptile growth of individual seeds was also related to the R(E) of each seed at 2-3 d after anoxia (r(2) = 0.46).
  • The relationship between coleopile elongation and alcoholic fermentation of rice under anoxia is examined using seeds either: (a) N-2 flushed during submergence, (b) incubated in stagnant deoxygenated agar at 0.1 % w/v to simulate the stagnant conditions of waterlogged soil, or (c) incubated in waterlogged soil. Coleoptile elongation growth was greater for N-2 flushing > stagnant agar > soil; seed survival was also greatest in this order over 1-5 d.

publication date

  • 1994
  • 1994