In vitro corm production in the saffron crocus (Crocus sativus L.)

Means to increase the reproductive capacity of Crocus sativus L., in vitro, are described. Cytokinins and auxin were found to be essential for development of bud explants. Ethylene and ethaphon pretreatments inhibited leaf development but induced corm production. Microsurgery of the apical bud combined with ethylene pretreatment increased both sprouting and corm production.     

Fruit thinning plums and apricots

The need for crop load reduction to improve fruit size andconsistency of cropping on plum and apricot trees is discussed. Threealternative strategies of achieving this objective are described: byinhibition of flowering, prevention of fruit set or stimulation ofincreased fruitlet abscission. Methods of achieving each of thesestrategies, by manual, mechanical or chemical means are discussed andevaluated.     

Insights into the toxicity mechanism of and cell response to the herbicide 2,4-D in plants

Although structurally similar to the natural plant hormone indol-3- acetic acid, auxin herbicides were developed for purposes other than growth, and have been successfully used in agriculture for the last 60 years. Concerted efforts are being made to understand and decipher the precise mechanism of action of IAA and synthetic auxins. Innumerable results need to be interconnected to resolve the puzzle of auxin biology and action mode of auxin herbicides. To date, different breakthroughs are providing more insights into the process of plant-herbicide interactions. Here we highlight some of the latest findings on how the 2,4-dichlorophenoxyacetic acid damages susceptible broadleaf plants, emphasizing the role of ROS as a downstream component of the auxin signal transduction under herbicide treatment.     

Isolation, partial chemical and biological characterization of thymone B

A new approach to the study of the molecular arrangements of proteins in membranes is described. Irradiation with visible light of native erythrocytes or washed erythrocyte membranes suspended in buffers containing a) riboflavin, fluorescein or fluorescein coupled to dextran and b) ³H-labelled tryptophan resulted in incorporation of radioactivity into the membrane proteins. Polyacrylamide gel electrophoresis of solubilized membranes followed by radioactivity measurements of the separated membrane proteins revealed that in native erythrocytes the protein components known to be located at the exterior cell surface, Band 3 and the major sialoglycoproteins became specifically labelled, whereas in washed lysed cells all of the major membrane proteins were labelled.     

Purification of aqueous ethylene glycol

Reagent-grade ethylene glycol has been shown to contain substantial amounts of aldehydes, peroxides, iron, and uv-absorbing hydrocarbons. These impurities can be removed by reduction with sodium borohydride, dilution with H2O, passing through a train of four columns, and filtering through a 0.45-micron filter. The product is stable for at least several months and perhaps much longer; storage under nitrogen in acid-washed dark bottles is preferable. Ten liters of 25% (v/v) aqueous ethylene glycol can easily be purified in about 1 week using equipment commonly available in a biochemical laboratory. This purification is also applicable to aqueous glycerol.     

Diazocyclopentadiene (DACP), a light sensitive reagent for the ethylene receptor in plants

Diazocyclopentadiene (DACP) has been shown to be an effective reagent for the ethylene receptor. Treatment of mung bean sprouts or tobacco leaves with DACP in the light or in the dark inactivates much of the ethylene binding. In the light, inactivation seems to be permanent, while in the dark, the site becomes active again after the DACP diffuses away. The compound is 10 times more effective in the light than in the dark. DACP inhibits banana ripening indicating the physiological receptor is involved. It also overcomes the inhibitory effect of ethylene on mung bean seedling growth (Km = 0.09 µl/1 E) at low ethylene levels. At high ethylene levels, an apparent high ethylene level site becomes apparent (Km = 50 µl/1 E) and growth is inhibited.     

The nature of iron released by resident and stimulated mouse peritoneal macrophages

Mouse peritoneal macrophages were allowed to ingest ⁵⁹Fe, ¹²⁵I-labelled transferrin-antitransferrin immune complexes, and the release of ⁵⁹Fe and degraded transferrin was studied. Some iron was released as ferritin, but a major portion was bound by bovine transferrin present in the culture medium, which contained fetal calf serum. If the medium was saturated with iron prior to incubation with the cells, little of the released iron was then bound by transferrin but appeared either as a high molecular weight fraction or, if nitrilotriacetate was present in the medium, some also appeared as a low molecular weight fraction. The release of non-ferritin iron was biphasic, the early, rapid phase being more prolonged with resident cells than with stimulated cells. The rate of release in the late phase did not differ significantly between resident and stimulated cells. Incubation at 0°C completely suppressed the release of degraded transferrin, but iron release continued at about 30% of the rate seen in control cultures at 37°C. A model for the intracellular handling of ingested iron is proposed to take account of the different release patterns of resident and stimulated macrophages.