It has recently been shown that asymmetric acid efflux is closely correlated with the gravitropic curvature of plant shoots and roots. The research reported here addresses whether auxin (IAA) redistribution in shoots is the cause or result of asymmetric acid efflux.When abraded sunflower (Helianthus annuus cv Mammoth) hypocotyls are submerged in 20 millimolar neutral buffer, gravicurvature is g...

The respiration of cut flowers of gerbera (Gerbera jamesonii H. Bolus ex Hook.f. 'Vesuvio') and sunflower (Helianthus annuus L.) increased exponentially with increasing storage temperature. Poststorage vase life and negatively gravitropic bending of the neck of the flowers were both strongly affected by simulated transport at higher temperatures. Vase life and stem bending after dry storage sho...

the nutrient deficiency. The apparent narrow temperature range of maximum growth found in the old cultures of Chlorella and Anacystis also seem to be caused by such secondary effects. We have therefore prepared table I from the earliest clear pattern that developed. It should represent the optimum conditions for cultivating these algae. In figure 4 the development of a Chlorella pyrenoidosa and...

The genotoxic effects of the herbicide oxyfluorfen on root meristem cells Heianthus annuus L. (sunflower) were investigated. roots treated with 75, 150, and 300 ppm concentrations for 12 24 h. different genetic endpoints such as mitotic index (MI), chromosome aberrations (CA), micronuclei (MN) analyzed in both control test groups. showed a marked mitodepressive action mitosis. Additionally, MN ...

Alternariaster was erected in 2007 to accommodate Alternaria helianthi, a fungal species known to cause leaf spots on Helianthus annuus (sunflower). It was segregated from Alternaria based on conidial morphology. Recently an unknown alternaria-like dematiaceous fungus was found associated with leaf spots on Bidens sulphurea (yellow cosmos) in Brazil. Based on a multi-gene phylogeny of parts of ...

A metal-resistant bacterial strain SM3 isolated from a serpentine soil in the north-east of Portugal was characterized as Bacillus weihenstephanensis based on the morphological and biochemical characteristics and on the comparative analysis of the partial 16S ribosomal DNA sequence. Bacillus weihenstephanensis SM3 showed a high degree of resistance to nickel (1500 mg l(-1)), copper (500 mg l(-1...

The Dwarf Sunflower, Helianthus annuus, is a hyperaccumulator of the heavy metals cadmium, nickel, and chromium. The molecular mechanism of hyperaccumulation and adapting to the resulting abiotic stress is largely unknown. Metal-binding and other proteins induced in response to stress conditions may play indispensable roles in allowing the metals to accumulate and the plant to adapt itself. How...

Lentz et al. (1) cite linguistic evidence supporting their hypothesis that Helianthus annuus was domesticated in Mesoamerica in pre-Columbian times. This consists, in part, of a list of names for sunflower collected from speakers of 14 contemporary native languages. They conclude that the fact that terms for sunflower in 11 of these languages do not phonologically resemble Spanish words for sun...