Mostrando recursos 1 - 2 de 2

  1. Growing pollen tubes possess a constitutive alkaline band in the clear zone and a growth-dependent acidic tip

    Feijó, JA; Sainhas, J; Hackett, GR; Kunkel, JG; Hepler, PK
    Using both the proton selective vibrating electrode to probe the extracellular currents and ratio-metric wide-field fluorescence microscopy with the indicator 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF)-dextran to image the intracellular pH, we have examined the distribution and activity of protons (Hf) associated with pollen tube growth. The intracellular images reveal that lily pollen tubes possess a constitutive alkaline band at the base of the clear zone and an acidic domain at the extreme apex. The extracellular observations, in close agreement, show a proton influx at the extreme apex of the pollen tube and an efflux in the region that corresponds to the position of...
    - 21-may-2011

  2. Nitric oxide is involved in growth regulation and re-orientation of pollen tubes

    Prado, AM; Porterfield, DM; Feijo, JA
    Nitric oxide (NO) controls diverse functions in many cells and organs of animals. It is also produced in plants and has a variety of effects, but little is known about their underlying mechanisms. In the present study, we have discovered a role for NO in the regulation of pollen tube growth, a fast tip-growing cellular system. Pollen tubes must be precisely oriented inside the anatomically complex female ovary in order to deliver sperm. We hypothesized that NO could play a role in this guidance and tested this hypothesis by challenging the growth of pollen tubes with an external NO point...
    - 21-may-2011

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