The present invention relates generally to the field of molecular biology and concerns a method for improving plant growth characteristics relative to corresponding wild type plants. More specifically, the present invention concerns a method for improving plant growth characteristics comprising modulating expression in a plant of a nucleic acid encoding a class I homeodomain leucine zipper (HDZip) hox5 polypeptide or a homologue thereof; or comprising modulating expression in a plant of a nucleic acid encoding a nitrate transporter protein (NRT) or a homologue thereof; or comprising modulating expression in a plant of a nucleic acid encoding a polypeptide denoted Yield Enhancing Protein 16 (YEP16); or comprising modulating expression in a plant of a Group I glycogen synthase kinase (Group I shaggy-like kinase) or a homologue thereof. The present invention also concerns plants having modulated expression of a nucleic acid encoding a class I HDZip hox5 polypeptide or a homologue thereof; or having modulated expression of a nucleic acid encoding a NRT protein or a homologue thereof; or having modulated expression of a nucleic acid encoding a polypeptide denoted YEP16; or having modulated expression of a Group I shaggy-like kinase or a homologue thereof, which plants have improved growth characteristics relative to corresponding wild type plants. The invention also provides constructs useful in the methods of the invention.