Antagonistic and Synergistic Interactions between Ancymidol and Gibberellins in Shoot Growth of Cucumber (Cucumis sativus L. )

Effects of the plant growth retardant, ancymidol, on the growthand morphology of the shoot system of cucumber (Cucumis sativusL. ) were investigated. Ancymidol inhibited stem elongation,reducing both number and length of internodes. Reduction inleaf area, attributable to a reduction in both cell size andnumber, was accompanied by an increase in chlorophyll per unitarea. The retardant decreased apical dominance and delayed anthesis.Gibberellic acid fully reversed ancymidol-induced inhibitionof stem elongation, internode length and production, and leafexpansion. GA_4/7 and ancymidol gave a synergistic promotionof stem elongation by increasing elongation of younger internodesand increasing internode production. Synergistic promotion ofpetiole elongation by this combination was also observed. Ancymidol,applied 7 d previously either to the shoot or root, severelyreduced the level of gibberellin-like activity in bleeding sapcollected from decapitated plants.     

Competition by, and chemical control of, natural weed populations in spring-sown field beans (Vicia faba)

A field experiment was done in 1974 to determine the effect of the presence of weeds for different periods on the yield of field beans (Vicia faba cv. Maris Bead). A critical period of weed competition of 2 wk duration occurred from 3 to 5 wk after 50% crop emergence. When weeds were not controlled, seed yield was reduced by 46%, from 4–6 to 2–5 t/ha. In another experiment, in 1975, there was no evidence of a critical period. Seed yield was reduced by 48%, from 2–9 to 1–5 t/ha, when weeds were not controlled. Pre-emergence applications of simazine and of dimefuron, a new soil-residual herbicide, effectively controlled weeds and bean seed yields were similar to those of the regularly hand-weeded control. Dinoseb-acetate and early, but not late, post-emergence applications of dimefuron controlled weeds satisfactorily. Dimefuron is potentially useful in spring-sown field beans because it can be applied pre- or early post-emergence without damaging the crop.     

Uptake and distribution of the growth retardant, aminozide, in relation to control of latera shoot elongation in Chrysanthemum morifolium

The uptake, stability and redistribution of the plant growth retardant, aminozide, in ‘pinched’ plants of Chrysanthemum morifolium Ramat. cv. Lemon Princess Anne were examined in relation to control of lateral shoot elongation. Foliar uptake was most rapid over the first few hours, and was almost complete within 72 h. More of the available aminozide was taken up by the young lateral shoots than by older foliage on the main stem. The aminozide content of entire plants generally remained constant over several weeks, indicating that the compound was relatively stable within the plant. The time scale and pattern of redistribution of foliar- and root-applied aminozide suggests that the compound may be translocated in both phloem and xylem. Spray application to young lateral shoots was as effective in controlling their elongation as application to all aerial organs. Basipetal transport of aminozide from lateral shoots was slight. The results are discussed in relation to the site of action of the compound and to its application in commercial practice.     

The FSG Oil Pollution Research Unit–the 1980s and beyond

Research into the effects of oil contamination in estuaries and coastal waters has been the fundamental aim of OPRU since its inception in 1967. The development of the Unit's research programme has taken place in response to the needs of government and industry. In recent years it includes moves into the international field and away from solely oil and marine projects. The accumulated research and educational experience has wide applications in future environmental monitoring, management and protection.