The cytological effects of pollen γ-irradiation at 50 and 100 krad on both embryo and endosperm development were studied in Malus × domestica. Fruit and seed set were reduced by increasing doses of pollen irradiation, while embryo sacs resulting from the treatments differed in number and morphology of endosperm nuclei and in the presence or absence of an embryo. Nuclear abnormalities, distinguished from normal nuclear behaviour in embryo sacs derived from unirradiated pollen, included enhanced numbers of polyploid restitution nuclei, bridges between nuclei, excluded metaphase chromosome fragments and disrupted mitotic synchrony. Generally, a high dose of pollen irradiation (100 krad) generated an all-or-nothing response in the embryo sac, either creating highly abnormal embryos and/or endosperms which aborted, or showing relatively normal development. Callus produced from excised cellular endosperm differed in average genome size, that derived from 100 krad pollen being smaller than that from unirradiated pollen.

The impact on hospital resources of variability in referral rates among general practitioners was of concern throughout the 1980s. The overall number of patients referred to outpatient clinics, however, has increased only slowly since the NHS began; in contrast, the number of new outpatients seen by each hospital consultant has declined appreciably. Ironically, despite this decline, further increasing the number of consultants in now being presented as a solution to the demand for outreach clinics in general practice.

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Variation in vegetative and reproductive growth patterns leading to summer flowering and fruiting was evaluated in everbearing and in representative Junebearing strawberry (Fragaria × ananassa Duch) clones under simulated summer conditions in the greenhouse and in growth chambers. Summer flowering intensity, periodicity, fruit set, and maturation were related to plant architectural parameters such as crown, leaf and runner production, number of meristems produced and differentiated, leaf areas and petiole length, plant volume, and dry weight allocation patterns. A continuum of growth habits and flowering behavior precluded rigid classification of summer flowering response, but useful arbitrary distinctions were made on the bases of: photoperiod reaction into short-day (Junebearing) vs. weak, intermediate, or strong day-neutrals; or summer fruit expectation into essentially none (Junebearing) vs. sporadic or consistent everbearers. Critical criteria for separating Junebearers from everbearers include degree of summer flowering and fruiting (fresh or dry weight basis), plant volume (and its components, petiole length, and average leaf area), and the dry weight allocation ratios—root : shoot and reproductive : vegetative. Everbearing (or day-neutral) types could be distinguished by plant volume and composition differences (size, number, and percentage of developed meristems, leaf area ratio, reproductive dry weight, etc.) and continuity of individual plant flowering. Three basic models of shoot growth and inflorescence positioning are proposed from evidence for alternative modes of flowering site generation in everbearing strawberries.