Beechnut Storage: A Review and Practical Interpretation of the Scientific Literature

Beechnuts are not easy to store or long-lived in storage. Theyexhibit storage characteristics between those of ‘orthodox’and ‘recalcitrant’ seeds. Superimposed upon thisis a pronounced dormancy which is overcome by between 4 and20 weeks of moist chilling. Pretreatment periods of 15–20weeks occupy most of the time between collection in Octoberand sowing the following April; hence short-term storage isa combination of moist storage and pretreatment. Most evidencepoints to the best short-term storage/pretreatment conditionsbeing 0–5°C at 28–32 per cent moisture content(m.c.) (fresh weight basis). Long-term storage requires a periodat low moisture content and the best conditions appear to be10 per cent m.c. and –10°C or below. The relative merits of overcoming seed dormancy before or afterdry storage are reviewed. There is no consensus about whichsequence is best but the former procedure is likely to be preferredby nursery managers because it allows storage of non-dormantnuts which can be withdrawn from store and sown immediately. Received 13 February 1990.     

Morphometric and meristic characters in salmon, Salmo salar L., trout, Salmo trutta L., and their hybrids

Abstract. Atlantic salmon, Salmo salar L., brown trout, S. trutta L. and their hybrids are normally identified in the field by empirical differences in maxilla length, thickness of the caudal peduncle, degree of forking of the tail and overall body conformation. This study quantifies these characters and analyses their variations in electrophoretically identified hatchery-reared individuals. Means and variances of the various measures are presented for salmon, trout and hybrids separately. The morphometric characters do not satisfactorily distinguish hybrids from the pure species, and even within samples of the pure species, some individuals will be misclassified as hybrids, or as members of the opposite species, if single characters are used on their own. Hybrids often resemble one or other parent species in one or more characters and are less often intermediate in phenotype. Triploidized hybrids are more like salmon than diploid hybrids are, and triploidized salmon are not different from diploid salmon. The results confirm that frequencies of hybrids of these species cannot be reliably assessed by morphological characters alone, and even for individuals of the pure parental species, independent confirmation of species status is advisable. Early reports of hybrid frequencies in wild stocks should be treated with caution, and apparently higher levels of hybridization in more recent studies compared with older, traditional surveys may simply reflect the greater precision of electrophoretic identification.     

Morphogenesis of syncytiotrophoblast in vivo: an autoradiographic demonstration

In an in vivo autoradiographic study of immature primate trophoblast, tritiated thymidine was first found only in nuclei of cytotrophoblast but after 22 hours, labeled nuclei appeared in syncytiotrophoblast as well. Hence syncytiotrophoblast of the monkey appears to originate by differentiation of cytotrophoblast.     

The Effect of Drying Quercus robur Acorns to Different Moisture Contents, followed by Storage, either with or without Imbibition

Freshly harvested Quercus robur acorns were spread out, twodeep, in trays, and dried/stored (at +2°C over the courseof 28 weeks) to either 45, 40, 35, 30 or 25 per cent moisturecontent (fresh weight basis). Drying/storage significantly reducedthe germination percentage (P< 0.01). The acorns at eachmoisture content were then either ‘soaked’ or ‘notsoaked’, before immediate germination; or returned tothe same cold store at +2°C, this time in loosely tied polythenebags. Soaking raised the acorns moisture content (M.C.), andalso brought about a significant increase in germination capacity(P<0.01). Regardless of the moisture content immediatelybefore soaking, "soaked" acorns in loosely tied polythene bagsstored better than ‘unsoaked’ acorns. All ‘bagged’acorns (whether ‘soaked’ or ‘unsoaked’)stored better than acorns dried/stored in open trays.