The embryo sac ofPodostemum subulatus (Podostemaceae) — a reinvestigation

The female gametophyte ontogeny inPodostemum subulatus is of the Apinagia type and not the Podostemum type as reported earlier. The independent existence of the Podostemum type in the family is questioned.     

Event recording in a clinical trial of a new medicine.

In a double-blind trial of the effect of zimelidine on weight and appetite 24 obese patients were allocated at random to receive either zimelidine or placebo for eight weeks followed by the alternative treatment for eight weeks. Possible adverse effects were elicited by asking patients at weekly intervals whether they had experienced any symptoms or ailments and recording all such "events" on a special form. A conventional checklist of symptoms was also used. Among 19 patients who completed the trial the two methods of recording yielded similar patterns of events. Of symptoms not on the checklist, insomnia was more common during treatment with zimelidine. Event recording was found to be a practicable and convenient method of detecting possible adverse effects.     

Osmotic Stress in Coleoptiles and Primary Leaves of Wheat: I. EFFECTS ON SIZE, WEIGHT, TOTAL PROTEIN, DNA, AND PHOSPHORUS

Seedlings of wheat (Triticum durum, cv. Balcarceño-INTA)were water-stressed in darkness with 20% polyethylene glycol(PEG) 6000 or 0.3 M mannitol added to the root medium. At differenttimes and up to a total of 36 h of treatment the coleoptileand primary leaves were cut and analysed. The height and freshweight of shoots were lower in treated plants than in controlplants. Dry weight was not significantly different between controland water-stressed plants. Total protein concentration decreasedsignificantly (P < 0.01) after 36 h of PEG 6000 treatment.Total DNA concentration decreased in controls but not significantly(P < 0.025) in treated seedlings. This result was interpretedas indicating that cell elongation prevailed over cell divisionin controls and that cell enlargement was affected in stressedplants. Total phosphorus concentration fell in control and treatedseedlings. However, phosphorus specific radioactivity increasedby 116% in control plants, 93% in mannitol-treated plants, and22% in PEG 6000-treated seedlings. These data suggest that anearly metabolic effect of water stress may be on phosphorusturnover in shoots.     

Affinity of intramitochondrial granules for ruthenium red accompanying induced cell death in chick embryos.

To test the hypothesis that ruthenium red binding of intramitochondrial granules might reflect an altered or pathological state of membranes associated with degeneration, embryos were treated with 6-AN to induce cell death in cartilaginous skeletons of chick embryos. Cervical cartilage from normal, 6-AN-treated and nicotinamide-alleviated 6-AN embryos was examined ultrastructurally for presence of IM RR-positive granules. Mitochondria of normal cervical chondroblasts which undergo normal phenotypic expression acquire RR-positive granules, although few mature cells are observed in young embryos. Necrotic chondroblasts, chondroblasts in various stages of degeneration, and proliferating chondrogenic cells of 6-AN-treated embryos all demonstrated induced RR-positive IM granules. Foci of degenerating chondroblasts, with mitochondria demonstrating RR granules, were observed infrequently in teratogen-alleviated tissue. The cytological features induced by 6-AN confirm its lethal effect and the degenerative effect on membranes presumably "unmasks" mitochondrial Ca-affinity sites which then become RR-positive. Cytochemical observations correspond with the biochemical and structural changes induced by 6-AN and confirm the hypothesis that RR-positive sites are the result of pathological changes.