Digital Photography as a Tool of Research and Documentation in Plant Tissue Culture.

Scientific photography is an important and indispensable tool in plant tissue culture research: photographs should be taken throughout a project for documentation. The aim of photography in plant tissue culture should be to illustrate clearly the differentiation, growth, and developmental stages occurring in vitro. Poor-quality scientific photography in tissue culture research and professional reports results in poor documentation.

Control of in vitro rooting and plant development in Corymbia maculata by silver nitrate, silver thiosulfate and thiosulfate ion.

Plant regeneration and transformation in vitro is often improved by adding silver ion (Ag(+)) to the culture media as AgNO(3) or silver thiosulfate (STS). Ag(+) reacts with substances to form insoluble precipitates, while thiosulfate (S(2)O(3) (2-)) interferes with these reactions. We studied the implications of silver precipitation and S(2)O(3) (2-) in the medium for culture development by (1) examining formation of Ag(+) precipitates from AgNO(3) versus STS in agar gels and their possible dependence on agar type; (2) comparing Corymbia maculata culture responses to AgNO(3) and STS and determining which better suits control of culture development; (3) clarifying whether STS-dependent alterations in culture development are due to Ag(+) alone or also to a separate influence of S(2)O(3) (2-).

Gene silencing of mannose 6-phosphate reductase in the parasitic weed Orobanche aegyptiaca through the production of homologous dsRNA sequences in the host plant.

Orobanche spp. (broomrape) are parasitic plants which subsist on the roots of a wide range of hosts, including tomato, causing severe losses in yield quality and quantity. Large amounts of mannitol accumulate in this parasitic weed during development.

Dependence of the phototropic response of Arabidopsis thaliana on fluence rate and wavelength.

In the phototropic response of Arabidopsis thaliana seedlings, the shape of the fluence-response relation depends on fluence rate and wavelength. At low fluence rates, the response to 450-nm light is characterized by a single maximum at about 0.3 mumol.

Mutants of Arabidopsis thaliana with decreased amplitude in their phototropic response.

Two mutants of Arabidopsis thaliana have been identified with decreased phototropism to 450-nanometer light. Fluence-response relationships for these strains (ZR8 and ZR19) to single and multiple flashes of light show thresholds, curve shapes, and fluence for maximum curvature in first positive' phototropism which are the same as those of the wild type. Similarly, there is no alteration from the wild type in the kinetics of curvature or in the optimum dark period separating sequential flashes in a multiple flash regimen.