Studies on sodium bypass flow in lateral rootless mutants lrt1 and lrt2, and crown rootless mutant crl1 of rice (Oryza sativa L.)

Bualuang Faiyue, Chenniappan Vijayalakshmi, Shafqat Nawaz, Yasuo Nagato, Shin Taketa, Masahiko Ichii, Mohammed J. Al-Azzawi, Timothy J. Flowers

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29 Citations (Scopus)


An apoplastic pathway, the so-called bypass flow, is important for Na+ uptake in rice (Oryza sativa L.) under saline conditions; however, the precise site of entry is not yet known. We report the results of our test of the hypothesis that bypass flow of Na+ in rice occurs at the site where lateral roots emerge from the main roots. We investigated Na+ uptake and bypass flow in lateral rootless mutants (lrt1, lrt2), a crown rootless mutant (crl1), their wild types (Oochikara, Nipponbare and Taichung 65, respectively) and in seedlings of rice cv. IR36. The results showed that shoot Na+ concentration in lrt1, lrt2 and crl1 was lower (by 20-23%) than that of their wild types. In contrast, the bypass flow quantified using trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS) was significantly increased in the mutants, from an average of 1.1% in the wild types to 3.2% in the mutants. Similarly, bypass flow in shoots of IR36 where the number of lateral and crown roots had been reduced through physical and hormonal manipulations was dramatically increased (from 5.6 to 12.5%) as compared to the controls. The results suggest that the path of bypass flow in rice is not at the sites of lateral root emergence.

Original languageEnglish
Pages (from-to)687-701
Number of pages15
JournalPlant, Cell and Environment
Issue number5
Publication statusPublished - May 2010
Externally publishedYes



  • Apoplastic transport
  • Na+ accumulation
  • PTS
  • Salinity

ASJC Scopus subject areas

  • Plant Science
  • Physiology

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