Smyrnium Olusatrum Research Articles

A furanoeudesmane from the fruits of Smyrnium olusatrum

In addition to two known acetoxy-eudesmanolides and two furanogermacranes from the fruits of Smyrnium olusatrum a new highly unstable acetoxy-furanoeudesmane was obtained, which obviously is the precursor of the two acetoxy-eudesmanolides.

An investigation of the host range of the carrot fly

SUMMARYThe historical records of the earliest reports of umbelliferous and other hosts of carrot fly (Psila rosae) are presented and their validity discussed. In addition, the results are reported of tests made between 1972 and 1980 on 27 species of Umbelliferae and three sub‐species of Daucus carota to determine whether they would support the carrot fly. Techniques were developed for identifying plant species as hosts by determining the number of adult flies that emerged from root and soil samples obtained from plants exposed to carrot fly in the field. Experiments in 1979 and 1980 indicating the importance of co‐ordinating the life cycles of plant and insect. The results showed that certain annual species of Umbelliferae were unsuitable as hosts in the autumn when they has flowered and senesced. Valid records could only be obtained for these species by exposing the plants to first generation carrot fly attack. Of the 27 species tested, Anthriscus sylvestris, Ferula communis, and Smyrnium olusatrum failed to support carrot fly and the following 13 species were new host records: Aethusa cynapium, Anthriscus caucalis, Apium inundatum, Apium nodiflorum, Bupleurum tenuissimum, Chaerophyllum temulentum, Cicuta virosa, Daucus capillifolius, Daucus glochidiatus, Heracleum mantegazzianum, Ligusticum scoticum, Oenanthe crocata and Sison amomum. From two species, Chaerophyllum temulentum and Torilis japonica, more than two carrot flies/root were recovered. These species are numerous and widespread in carrot‐growing districts. The significance of these and other wild host plants in relation to the ecology and control of carrot fly is discussed.

FLORAL SEX RATIOS IN ANDROMONOECIOUS UMBELLIFERAE

SUMMARYThe distribution of hermaphrodite and male flowers was determined in the inflorescences of three andromonoecious species of Umbelliferae, Smyrnium olusatrum, Pastinaca sativa and Anthriscus sylvestris. Despite wide differences in the number of flowers produced per plant by the three species the floral ratio 4 male to 1 hermaphrodite was remarkably constant and except in an extreme environment 55 to 70 % of hermaphrodite flowers produced ripe seeds. The constancy in floral ratio per plant was maintained by quite different distributions of flower type between umbels in the three species. The apparent contradiction between protandry in flowers but protogyny within umbels is interpreted as an avoidance of simultaneous competition for resources within the plant.

THE RESOURCE COSTS OF GENDER AND MATERNAL SUPPORT IN AN ANDROMONOECIOUS UMBELLIFER, SMYRNIUM OLUSATRUM L.

SUMMARYIn hermaphrodite flowers the various organs are potentially in competition with each other for resources translocated via the peduncle. It is an interesting question to ask: in what proportions does a plant with hermaphrodite flowers allocate various potentially limiting resources between these potentially ‘competing’ organs – between sporophylls and organs of attraction (petals, nectaries) and between stamens and pistils? The question becomes even more interesting in an andromonoecious species in which the plant supplies resources to both male and hermaphrodite (perfect) flowers.In the biennial andromonoecious umbellifer Smyrnium olusatrum L. a constant ratio of one hermaphrodite flower to four staminate flowers was found to be maintained despite a fivefold range in both total flower number and total plant dry wt produced by surgery and nutrient depletion.The allocation of nitrogen, phosphorus and potassium in floral organs was studied in S. olusatrum that had received various experimental treatments.The ratio of resource allocated to sporophylls and to ancillary attractive organs was found to remain relatively constant whereas the allocation to the two types of attractive organs (petals and stylopodia) tended to vary with the experimental manipulations. The relative allocation of nutrient resources to male and female activities was scarcely altered by the treatments. Before fertilization plants distributed a greater (c. fivefold) proportion of phosphorus to male than to female organs. However, the cost of placental support of developing embryos reversed the ratio such that at seed maturity a greater proportion of phosphorus (c. × 2) had been allocated to seed than to stamens.

Experimental manipulation of patterns of resource allocation in the growth cycle and reproduction of Smyrnium olusatrum L.

Plants of the monocarpic (normally biennial) Smyrnium olusatrum (Umbel]iferae) were grown in pots in soil at a high or low nutrient regime. Some plants receiving full nutrients were grown in a heated glasshouse with 16 h days. The remainder were grown without supplementary lighting or heat and included control plants and others which received surgical treatment after ten months growth: deradication (removal of half of the root stock); defoliation; deradication and defoliation. The distribution of plant biomass and of phosphorus were analyzed at the time of seed set. Patterns of allocation of dry matter and phosphorus were quite different and were significantly altered by treatments, which produced a range of allocation to reproductive structures ranging from 21 to 74% of total phosphorus and 12 to 35% of dry matter. Distribution patterns of total phosphorus are discussed in terms of the potential demands being made by alternative structures and functions over the life cycle of the plants.

Periodicity of Seedling Emergence and Seed Survival in some Umbelliferae

(1) Among ten species of Umbelliferae there were differences both in the times of year at which seedlings emerged and in the extent to which seeds survived in cultivated soil. (2) The main time of emergence of Smyrnium olusatrum was in the autumn of sowing, while that of Anthriscus sylvestris, Heracleum sphondylium, Angelica sylvestris, Conopodium majus and Pastinaca sativa was in the following spring. Few viable seeds of these species remained after a year. (3) Seeds of Sison amomum, Conium maculatum and Torilis japonica survived for longer. Sison amomum had autumn and spring peaks of emergence, while Conium maculatum and Torilis japonica were mainly spring-germinating. (4) Maximum emergence of the spring-germinating annual weed Aethusa cynapium occurred in the second or third year, and about one-fifth of the seeds were still viable and dormant after 5 years.

An Investigation of Leaf Palatability Using the Snail Cepaea Nemoralis L.

palatability. Comparison of crop plants with uncultivated species provides a marked contrast with respect to palatability. Many wild plants are known to be partially or wholly inedible to the majority of herbivores; chemical and physical features protective against grazing and browsing are various and effective. The appearance of such features as characteristics of genera (e.g. Ulex), tribes (e.g. Compositae-Cynareae) or possibly even families (e.g. Ranunculaceae) is perhaps evidence of a long history of selection against palatability. Despite the efficacy and immediate selective advantage of mechanisms protecting plants from consumption it is interesting to find that contemporary natural and semi-natural vegetation invariably includes plants which are palatable to many herbivores. Certain of these plants, e.g. Poapratensis,* Onobrychis viciifolia and Smyrnium olusatrum, have been subjected to periods of cultivation. Study of palatable but uncultivated plants may enable us to define the circumstances in which selection for palatability occurs in natural vegetation. There are additional problems associated with palatability which are worthy of attention. It would be of value to distinguish between selection pressures conducive to the evolution of repulsive plants and those favouring palatable species with growth forms adapted to withstand regular defoliation, e.g. many grasses. Herbivorous animals differ considerably in their effect on vegetation. In particular, differences occur between vertebrates and invertebrates. To larger mammals, only the top of the plant may be accessible. Gasteropods, on the other hand, tend to concentrate on the lower foliage. Other more subtle differences in the damage caused by herbivores arise from differences in features such as the size of the animal, the form and effectiveness of the mouth parts, the annual and diurnal pattern of feeding and dependence on various sensory organs for food-finding and discrimination. In view of these differences it would appear worth-while to classify the 'defence mechanisms' of plants in terms of the herbivores against which they are most effective. This may permit a calculation of palatability in any particular circumstance as the product of an interaction of plant and animal attributes. This paper is a contribution to the areas of study which have been outlined, and concerns an attempt to measure the palatability of leaves of a range of flowering plants to the snail Cepaea nemoralis. The plants examined include species of known palatability to