C. album

In full-season soybeans and sunflowers planted into desiccated green rye, the elimination of tillage and the presence of rye mulch reduced aboveground biomass of C. album, A. artemisiifolia, and A. retroflexus 99,... 

The following chemicals were obtained commercially (Sigma Chemical Co.) and bioassayed with C. album and Amaranthus retroflexus L. (seeds collected in North Carolina in 1980) following identification DL-3-hydroxybutyric acid (DL-3-hydroxy-butyric acid as a Na salt) and L-3-phenyllactic acid (L-2-hydroxy-3-phenyl-propanoic acid). 

Rye Mulch Studies. Extraction of the dried aqueous extract (Figure 1) with methanol gave a preparation which showed the greatest activity, giving 58, 80 and 86% inhibition of C. album hypocotyl length, root length and germination, respectively (data not shown). Therefore, methanol was used for all subsequent transfers. 

Figure 3. The effect of DL-B-hydroxybutyric acid ( HBA) and L-g-phenyllactic acid (BPLA) on C. album hypocotyl length (HL).

There was little difference in response between the two weed species to gHBA (a 30% inhibition at 8 mM for (Z. album versus 27% for A. retroflexus). There was no significant interaction effect on HL between the two compounds (F = 0.97, P > F 0.50). The difference in sensitivity of the weed species to the two compounds could have been due to the duration of the experiments (8 days for C. album versus 60 hr for A. retroflexus). The longer duration may have resulted in a lower concentration of the compound because of microbial degradation. 

Canarium album Raeusch., C. sinense Rumph., C. album Raeusch., Pimela alba Lour. 

Precursor Plants Rare events in populations generally cannot be detected unless 1,000 or more individuals are analyzed from each location. However, we proceeded in a slightly different manner. Seedlings of C. album were collected in areas that have never been treated with cEemicals. When transplanted in a greenhouse, one leaf per plant was cut off and left to absorb atrazine in the dark and then the amounts of chlorophyll fluorescence were recorded. 

In addition, we observed that Type I mutants have all of their psbA gene copies mutated (99.9% probability) while no heteroplasmicity was found in Sp. plants (19). This indicates that a mechanism other than a high mutation rate must work to allow the release of individual plants that have their entire chloroplast population mutated. This could be due to the control of chloroplast DNA replication directed by mitochondrial or nuclear genomes. Indeed, a sequence homology has been found between mitochondrial DNA and part of the chloroplast psbA gene. Moreover, this homologous sequence is expressed as an RNA transcript in atrazine resistant C. album only and not in the susceptible plants (30). 

The Search for Resistant Plants The search for Sp. and Type I mutant plants in populations from cultivated fields failed. These plants, as well as many other types of mutants may have been eliminated because cultivation and other cultural practices have reduced the polymorphism of field populations (32). Moreover, Type I mutants probably have a low fitness value in the absence of tria-zines (16). The fact that mutants originate from only one or very few types of individuals in a population represents a bottleneck to the spread of resistance. Hence, resistance certainly evolved in fewer locations than could have been expected. For instance, no resistant C. album plants were found in Burgundy while Sp. mother plants having Type I descendants were found in gardens in Burgundy. 

A second bottleneck to the spread of the resistance was found in C. album populations. The Type I mutants were resistant to 0.5 kg a.i./ha only and 100% mortality was reached with 1 kg a.i./ha (19), while the actual dose used in corn fields was at least 1.5 kg a.i./ha (the lethal dose for susceptible plants is 0.1 kg a.i./ha). 

Figure 3. shows data for C. album and D.purpurea in response... 

Figure 4. shows part of the fluorescence data from idiich figure 3. was calculated Whilst in D. purpurea there is a significant dip in the fluorescence (Fg) following the decrease in irradiance before the level recovers, this dip is absent in C album. Such a dip can be induced by using a more intense hi light... 

Lamiaceae terpinen-4-ol of B. danthoniae, B. intermedius, A. retroflexus, C. dactylon, C. album, and L. serriola ... 

Lamiaceae borneol, terpineol C. album, P. oleracea, E. crus-galli, C. armuum, good inhibition rates against C. solstitialis, S. arvensis, and R. raphanistrum and wheat seeds (1992), Dudai et al. (1999), Azirak and Karaman (2008), and Angelini et al. (2003)... 

Lamiaceae y-terpinene, yr-cymene e.g., dandelion leaves, C. album, A. artemisi olia, S. halepense (1992), Angelini et al. (2003), and Tworkowski (2002)... 

Tanacetumaucheranum and Tanacetum chiliophyllum var. chiliophyllum, Asteraceae, are common in Europe and Western Asia. The essential oils were tested about their potential to inhibit germi nation and seedling growth of A. retroflexus, C. album, and R. crispus, in which they were very successful. Besides their herbicidal effect, they also have an antibacterial and antifungal activity (Salamci et al., 2007). 

N-Dealkylation also plays a role in the metabolism and selectivity of 5-triazine herbicides such as atrazine," simazine, simetryn, and ter-butryn. In species in which this pathway was prominent, the major products identified were monodealkylated triazines, which retained phytotoxicity. However, in a study of atrazine metabolism in C. album, C. strictum, and Amaranthus ponelli, Khan et al. identified the bound residue from resistant biotypes as N-desethylatrazine and suggested that sequestration of ph3 otoxic metabolites contributed to tolerance to the herbicide. " ... 

Synonyms C. anindolicum, C. album, C, decolorans and C. diversum [99], E, freundii (Braak) [96], Paracolohactrum intermedium [40], Bethesda Group [45, 46, 47], Ballerup Group [57], Intermedins [81], Bethesda-Ballenip Group [7], Citrobacter Group [82]. 

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