AERENCHYMA FORMATION IN MAIZE PLANTS UNDER PHOSPHORUS DEFICIENCY

Abstract

The objective of this work was to verify, under phosphorus stress (P), possible alterations to the root anatomy of maize inbred line A188 and its transgenic version having the genetic construction AtPT2::GUS. AtPT2::GUS plants were used as a positive control to validate the P stress, once this promoter directs GUS reporter gene expression only to the roots under P deficiency. Plants from inbred line A188 and its transgenic version were grown in nutrient solution with or without P. Fifteen days after initiating P stress, the root of seedlings were collected and submitted to the histochemical assay of GUS and to anatomical analyses. The formation of aerenchyma was observed 5 to 7.5 cm from the root apex in the P stress environment, containing the distal and medial zones of the roots. The presence of aerenchyma was observed in roots of both transgenic and non-transgenic seedlings. Thus, it could be verified that roots from inbred line A188, under P stress, show anatomic modifications (aerenchyma), which seem to be an adaptation of the plant aiming to reduce metabolic root costs for growth and soil exploration.

Keywords

• Inbred line
• AtPT2 promoter
• nutrient solution
• Zea mays L