Physiological roles for aerenchyma in phosphorus-stressed roots

To test this hypothesis we investigated aerenchyma formation, root respiration and tissue phosphorus concentration in maize and common bean genotypes in response to phosphorus availability and ethylene treatments

Mingshou Fan

2003

Scholarcy highlights

  • Low phosphorus availability is a primary constraint to plant growth in many terrestrial ecosystems
  • By the 12th day, when aerenchyma were extensive in the basal parts of low-phosphorus roots, the respiration rates in the basal and middle regions of seminal roots from plants grown in low phosphorus were significantly lower than those of high-phosphorus plants of genotype OH43
  • We found a substantial effect of low phosphorus on aerenchyma formation in maize seedling roots
  • Previous work showed that adventitious and seminal roots of maize seedlings responded to nitrogen and phosphorus deprivation with increased aerenchyma formation, in the basal segments of the root, the effect of omitting phosphorus was relatively minor in these reports (Konings and Verschuren
  • The greater effect of low phosphorus on maize aerenchyma in our experiments may have been due to the maize genotypes we employed, since we found significant genetic variation for aerenchyma formation in response to low phosphorus availability, as well as the greater age of the maize seedling roots examined (12 d in Table 1 vs 4 d after transplanting in previous workDrew et al
  • There was no significant difference in phosphorus concentration between roots of the two genotypes
  • We found that differences in aerenchyma formation induced by ethylene treatments and genotypic variation were correlated with proportionate reductions in root phosphorus concentration in both high-phosphorus and low-phosphorus roots
  • Our results support the hypothesis that aerenchyma formation reduces the respiratory and phosphorus requirements of soil exploration by roots, and represents a useful adaptation to low phosphorus availability

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