Nocturnal changes in leaf growth of Populus deltoides are controlled by cytoplasmic growth
2006 (English)In: Planta, ISSN 0032-0935, E-ISSN 1432-2048, Vol. 223, no 6, 1315-1328 p.Article in journal (Refereed) Published
Growing leaves do not expand at a constantrate but exhibit pronounced diel growth rhythms.However, the mechanisms giving rise to distinct dielgrowth dynamics in different species are still largelyunknown. As a first step towards identifying genescontrolling rate and timing of leaf growth, we analysedthe transcriptomes of rapidly expanding and fully expandedleaves of Populus deltoides Bartr. ex. Marsh atpoints of high and low expansion at night. Tissues withwell defined temporal growth rates were harvested usingan online growth-monitoring system based on a digitalimage sequence processing method developed forquantitative mapping of dicot leaf growth. Unlike plantsstudied previously, leaf growth in P. deltoides wascharacterised by lack of a base-tip gradient across thelamina, and by maximal and minimal growth at duskand dawn, respectively. Microarray analysis revealedthat the nocturnal decline in growth coincided with aconcerted down-regulation of ribosomal protein genes,indicating deceleration of cytoplasmic growth. In asubsequent time-course experiment, Northern blottingand real-time RT-PCR confirmed that the ribosomalprotein gene RPL12 and a cell-cycle gene H2B weredown-regulated after midnight following a decrease incellular carbohydrate concentrations. Thus, we proposethat the spatio-temporal growth pattern in leaves ofP. deltoides primarily arises from cytoplasmic growthwhose activity increases from afternoon to midnight andthereafter decreases in this species.
Place, publisher, year, edition, pages
Berlin: Springer-Verlag , 2006. Vol. 223, no 6, 1315-1328 p.
Cell cycle, cytoplasmic growth, leaf growth, microarray, populus, ribosomal protein
IdentifiersURN: urn:nbn:se:umu:diva-5383DOI: 10.1007/s00425-005-0181-0OAI: oai:DiVA.org:umu-5383DiVA: diva2:144882