Visualisation of plastid outgrowths in potato (Solanum tuberosum L.) tubers by carboxyfluorescein diacetate staining.

We describe two types of plastid outgrowths visualised in potato tubers after carboxyfluorescein diacetate staining. Probable esterase activity of the outgrowths has been demonstrated for the first time ever. Plastid outgrowths were observed in the phelloderm and storage parenchyma cells of red potato (S.

Mitogen-activated protein kinase 4 is a salicylic acid-independent regulator of growth but not of photosynthesis in Arabidopsis.

Mitogen-activated protein kinase (MAPK) pathways regulate signal transduction from different cellular compartments and from the extracellular environment to the nucleus in all eukaryotes. One of the best-characterized MAPKs in Arabidopsis thaliana is MPK4, which was shown to be a negative regulator of systemic-acquired resistance. The mpk4 mutant accumulates salicylic acid (SA), possesses constitutive expression of pathogenesis-related (PR) genes, and has an extremely dwarf phenotype.

Isochorismate synthase 1 is required for thylakoid organization, optimal plastoquinone redox status, and state transitions in Arabidopsis thaliana.

Isochorismate synthase 1 (ICS1) is a crucial enzyme in the salicylic acid (SA) synthesis pathway, and thus it is important for immune defences. The ics1 mutant is used in experiments on plant-pathogen interactions, and ICS1 is required for the appropriate hypersensitive disease defence response. However, ICS1 also takes part in the synthesis of phylloquinone, which is incorporated into photosystem I and is an important component of photosynthetic electron transport in plants.

Movement of fluorescent dyes Lucifer Yellow (LYCH) and carboxyfluorescein (CF) in Gaertn. roots and root nodules.

Lucifer Yellow (LYCH) and carboxyfluorescein (CF) served in roots and root nodules as the markers of apoplastic and symplastic transport, respectively. The aim of this study was to understand better the water and photoassimilate translocation pathways to and within nodules. The present study shows that in damaged roots LYCH moves apoplastically through the vascular elements but it was not detected within the nodule vascular bundles.

Vacuolar organization in the nodule parenchyma is important for the functioning of pea root nodules.

Different models have been proposed to explain the operation of oxygen diffusion barrier in root nodules of leguminous plants. This barrier participates in protection of oxygen-sensitive nitrogenase, the key enzyme in nitrogen fixation, from inactivation. Details concerning structural and biochemical properties of the barrier are still lacking.