Relationships between alkaloids in reed canarygrass (Phalaris arundinacea), soil moisture and nitrogen fertility

Abstract. The alkaloids of reed canarygrass respond to changes in soil moisture and nitrogen fertility. Gramine and hordenine levels increased under field conditions of moisture deprivation and this effect was enchanced when nitrogen fertilizer was applied. The level of 5-methoxy-N-methyltryptamine was affected mainly by the nitrogen amendment. Exceptional alkaloid levels in reed canarygrass are interpreted in relation to climatic and plant osmotic parameters. Improved TLC fluorescence scanning procedures are presented for quantifying reed canarygrass alkaloids.     

Control by imazalil of fruit storage rots caused by Alternaria alternata

The fungicide imazalil has potential value for controlling post-harvest diseases caused by Alternaria alternata in pears, apples and persimmons. Imazalil was active in vitro on germination and hyphal growth (ED₅₀) at 1.4 and 0.5 μg/ml, respectively. Protectant action of the fungicide lasted only 1 day after treatment. At 1000 μg/ml the fungicide inhibited development of Alternaria rot in inoculated apples at 0 °C and in naturally infected pears and persimmons at–1 °C.     

Comparative study of leaf anatomy of Malaysian species of Chionanthus and Olea (Oleaceae) with special reference to foliar sclereids

The foliar anatomy of 15 Malaysian species of Chionanthus and 3 species of Olea is described and compared with particular reference to sclereids. The anatomy of the two genera is similar except that Chionanthus shows a wider range in sclereid form, eight kinds ofsclereid are recorded. Filiform sclereids are present in all Olea species and most Chionanthus species examined, additional kinds ofsclereid found in these Chionanthus species include astrosclereids, dendrosclereids, osteosclereids and polymorphic sclereids, with brachysclereids of several forms in the petiole. Quantity of sclereids is not related to coriaceousness, which is determined by leaf thickness. Anatomical characters do not support any major grouping of species within Chionanthus and provide further evidence that the sections, Eulinocitra and Ceranthus , are untenable. The distinction between the lepidote scales of Olea and the peltate hairs common to all oleaceous genera is discussed.     

Flowering dynamics of Orchis morio L. and Herminium monorchis (L.) R.Br, at two sites in eastern England

Information taken from two long-term demographic studies on Orchis morio L. and Herminium monorchis (L.) R.Br, is used to explore some of the factors which influence flowering. The proportion of plants which flowered each year varied considerably between species, flowering in O. morio exceeding 40% in all years except one over an 18 year period; over a 30 year period (1966–95), the number of plants of Herminium in flower never exceeded 36% of the population and no inflorescences were produced in 1977 and 1991. The relationship between flowering in Herminium in a given year and the monthly rainfall and temperature for the current and 3 previous years was analysed using logistic regression. Best fits were obtained using data for the summer months in the previous year, with an increasing flowering rate with rainfall and a decline with temperature. It is hypothesized that drought and high temperatures in the summer reduce leaf area and cause premature senescence and the death of leaves, with the result that not enough carbohydrates are stored to enable plants to support or initiate inflorescences the following year. For species such as Orchis morio which produce leaves in the autumn and remain green, summer drought causes no problems as they have no above ground organs. Factors which influence flowering in this species are as yet unknown.     

Seeing the Past: Visual Media in Archaeology

As digital media become increasingly affordable and accessible, visual representation in archaeology is expanding across several dimensions. In this essay, I examine some emerging forms of visual media in archaeology, including online documentaries, maps and photographs, hypermedia, experimental films, and peripatetic video. Visual media offer powerful opportunities for engagement with the public. In addition, archaeologists are finding new ways to use the visual in interpretation, analysis, and critique. Experimental visual works often are self-consciously reflexive, questioning and exposing the ways archaeological knowledge is constructed, represented, and disseminated.