We describe a novel phenotype in Arabidopsis embryos homozygous for the temperature-sensitive topless-1 mutation. This mutation causes the transformation of the shoot pole into a root. Developing topless embryos fail to express markers for the shoot apical meristem (SHOOT MERISTEMLESS and UNUSUAL FLORAL ORGANS) and the hypocotyl (KNAT1). By contrast, the pattern of expression of root markers is...

Plant architecture is regulated by endogenous developmental programs, but it can also be strongly influenced by cues derived from the environment. For example, rhizosphere conditions such as water and nutrient availability affect shoot and root architecture; this implicates the root as a source of signals that can override endogenous developmental programs. Cytokinin, abscisic acid, and caroten...

In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NP...

Hydraulic conductance exerts a strong influence on many aspects of plant physiology, namely: transpiration, CO2 assimilation, growth, productivity or stress response. However we lack full understanding of the contribution of root or shoot water transport capacity to the total water balance, something which is difficult to study in trees. Here we tested the hypothesis that whole plant hydraulic ...

a hydroponic experiment was conducted to evaluate the effects of salt stress on safflower genotypes under greenhouse conditions. the experiment was arranged as a factorial one based upon a completely randomized design with three replications. five safflower genotypes (arak2811, nebraska10, sod25, ca116, and ca128), and four salinity treatments (0, 0.3, 0.5, and 0.7 percent of nacl) were employe...

Mutation of the SCARECROW (SCR) gene results in a radial pattern defect, loss of a ground tissue layer, in the root. Analysis of the shoot phenotype of scr mutants revealed that both hypocotyl and shoot inflorescence also have a radial pattern defect, loss of a normal starch sheath layer, and consequently are unable to sense gravity in the shoot. Analogous to its expression in the endodermis of...

seeds of most crops including those of range plants follow orthodox behavior. however, these seeds undergo aging even under favorable conditions, so that decreased viability and vigor related parameters are the main characteristics of deteriorated seeds. the effects of hormonal priming with auxin, cytokinin, gibberellin and abscisic acid at 0, 50, 100 and 150 ppm on physiological quality of tal...

The plant hormones cytokinins (CKs) regulate multiple developmental and physiological processes in Arabidopsis (Arabidopsis thaliana). Responses to CKs vary in different organs and tissues (e.g. the response to CKs has been shown to be opposite in shoot and root samples). However, the tissue-specific targets of CKs and the mechanisms underlying such specificity remain largely unclear. Here, we ...