Nitric oxide increases the level of chlorophyll in maize leaves with interveinal chlorosis.

GRAZIANO, M; BELIGNI, MV; LAXALT, AM; LAMATTINA, L

Conferencia; First International Conference on the Biology, Biochemistry and Therapeutical Applications of Nitric Oxide.; 2000

In previous works we have demonstrated the capacity of nitricoxide (NO) to preserve the level of chlorophyll in potato leaves bothinfected by the pathogen Phytophthora i. or treated with methylviologen herbicides. In other report, we also gave evidences that NOpromotes some processes mediated by light like deetiolation, seedgermination and inhibition of hypocotyl elongation. Here, we reportthat maize (Zea mays cv Canner) plantlets develop interveinal chlorosis when growing in conditions of moderately high temperature(25-33ºC), low radiation (200 mE m-2 s-1) and 14h photoperiod. Weshow that application of NO prevents the interveinal chlorosis ofmaize leaves. Two NO donors, sodium nitroprusside (SNP) andS-nitroso-N-acetilpenicyllamine (SNAP) produced in average a 28%and 40% increase of chlorophyll content in the veinal and interveinalregions respectively, when compared to controls. This effect wasarrested by addition of the NO scavenger carboxy-PTIO. In controlexperiments, oxidized products of NO, such NO2- and NO3-, wereunable to prevent chlorosis. Moreover, the greening of leaves wasdose-dependent for SNP with a maximum response in the rangebetween 100-500mM. Micromolar amounts of SNP producesnanomolar levels of NO. In addition, NO was also able to greenleaves that initially developed chlorotic. Interestingly, the ?yellowstripe? phenotype of a mutant maize (ys-3) was also partially reverted by NO