Reduction of Fe(III)EDTA by excised roots of soybean seedlings (Glycine max L.) is stimulated by l-malate in the bathing solution. Reduction occurs much more rapidly with roots of seedlings grown in the absence of iron than with roots of seedlings grown with iron. Cell-wall preparations from these roots catalyze reduction of Fe(III)EDTA by NADH. They also contain NAD(+)-dependent l-malate dehyd...

Roots growing under low water potential commonly exhibit a marked decrease in growth rate and in diameter. Using median longitudinal sections of fixed maize (Zea mays L. cv WF9 x Mo 17) seedling roots, we investigated the cellular basis for these effects. Cortical cells in the shortened elongation zone of water stressed roots were longer than cortical cells in the comparable location of well-wa...

Arabidopsis thaliana is a widely used model plant for plant biology research. Under traditional agar-plate culture system (TPG, traditional plant-growing), both plant shoots and roots are exposed to illumination, and roots are grown in sucrose-added medium. This is not a natural environment for the roots and may cause artifact responses. We have developed an improved agar-plate culture system (...

In the rain forests of Costa Rica, there is an unusual type of tree known as a “walking tree.” It is a strange looking tree. At the base of the tree is a tangle of roots, rising about a meter above the ground. It looks as if someone yanked the tree straight up out of the ground, leaving about a meter of its roots exposed above ground level. According to rain-forest guides, the walking tree actu...

The underground plant parts of reed (Phragmites australis) growing in anoxic soil of the littoral zone of lakes are provided with oxygen via an aerenchyma. Some of this oxygen is released into the rhizosphere, which creates a potential microhabitat for aerobic fungi. Although fungal endophytes of reed have been shown to occur also in roots of flooded habitats, it is not known whether or how fun...

Eight endoparasitic nematode species were recovered from 170 maize root samples in western Transvaal, Republic of South Africa. Pratylenchus zeae had the highest average population density (17,454/5 g roots), followed by P. neglectus (5,827/5 g roots), P. penetrans (5,617/5 g roots), P. brachyurus (3,060/5 g roots), Meloidogyne incognita plus M. javanica (301 juveniles/5 g roots), P. crenatus (...

White lupin (Lupinus albus) is able to adapt to phosphorus deficiency by producing proteoid roots that release a huge amount of organic acids, resulting in mobilization of sparingly soluble soil phosphate in rhizosphere. The mechanisms responsible for the release of organic acids by proteoid root cells, especially the trans-membrane transport processes, have not been elucidated. Because of high...

The rice endophyte Harpophora oryzae shares a common pathogenic ancestor with the rice blast fungus Magnaporthe oryzae. Direct comparison of the interactions between a single plant species and two closely-related (1) pathogenic and (2) mutualistic fungi species can improve our understanding of the evolution of the interactions between plants and fungi that lead to either mutualistic or pathogen...

an efficient transformation system for the medicinal plant portulaca oleracea was established using agropine-type agrobacterium rhizogenes atcc15834. hairy roots were obtained directly from cotyledon leaves explants seven days after inoculation with the bacteria. the highest transformation efficiency was obtained from cotyledon leaves explants, and amounted to 53.3% within two weeks. roots grew...

silymarin production by hairy root culture of milk thistle (silybum marianum l. gaertn) was investigated using agrobacterium rhizogenes ar15834. hairy roots were induced by injection or inoculation of explants with a. rhizogenes. one month old hairy roots were dissected from the explants and grown in murashing and skoog (ms) liquid medium. polymerase chain reaction (pcr) using the b gene and th...