Nitrate reduction in tendrils of semi-leafless pea.
The recessive gene af produces a modification of Pisum sativum L. leaf morphology, where leaflets are replaced by tendrils. Previous reports have suggested that tendrils may contribute to plant growth in a similar way to flat leaf structures, but these reports have been restricted to carbon metabolism. In this work, we investigate the nitrate reduction (nitrate reductase activity) capacity of tendrils of a semi-leafless variety, Solara, in relation to other leaf structures. Maximum nitrate reductase activity (EC 1.6.6.1), expressed on a protein basis, was significantly lower in tendrils compared to flat structures. However, the activation state of nitrate reductase was significantly higher in tendrils, reaching 70%, compared to flat leaf structures. According to these results, tendrils contributed up to 25% of the overall plant nitrate reduction in the semi-leafless variety. This figure was even higher when nitrate reduction was calculated from in vivo measurements. The results are discussed in relation to nitrate, magnesium, carbohydrates, amino acids and adenylate levels of tendrils.
González
Esther M.
EM
Departamento de Ciencias del Medio Natural, Universidad Pública de Navarra, Campus Arrosadía, E-31006 Pamplona, Spain.
Cabrerizo
Pablo M.
PM
Royuela
Mercedes
M
Aparicio-Tejo
Pedro M.
PM
Arrese-Igor
Cesar
C