Transectional studies of Lasthenia californica in the Jasper Ridge Biological Preserve (Stanford University) have documented the existence of two races (A and C) based upon flavonoid chemistry, achene morphology, allozymes, and flowering time differences. The two races coexist on a serpentine outcrop and have maintained a sharply defined pattern of distribution for a period of at least 15 yr. The present study has revealed significant differences in the physical and chemical features of the soils harboring the two races. Soils at the lower ends of the transects, where race A plants grow, have higher pH, cation exchange capacity, relative water content, total ionic strength, percentage clay, and sodium and magnesium concentrations than do soils harboring race C plants at the upper ends of the transects. Soils supporting race C plants have higher calcium, potassium, and nickel concentrations and higher calcium:magnesium ratios. Plant tissue concentrations of ions were also significantly different in the two races. Race A plants accumulated sodium to concentrations three times those observed with race C plants. Plants from an additional 22 sites gave very similar results. Greenhouse studies indicated that the two races from Jasper Ridge show differential responses to ridge-top and ridge-bottom soils. Race A achenes germinated, grew to maturity, and set seed about equally in the two soils. Race C achenes germinated in both types of soils but showed significantly poorer growth and absolutely no flowering when found in the soils of race A plants. Differential responses to edaphic conditions on the ridge may contribute to the pattern of distribution observed over the years. It is suggested that race A plants are more tolerant of edaphic stress than race C plants and that physiological specialization may contribute to the present distribution of the two races throughout the species' range. It is not yet possible to state which is the more significant factor in driving this specialization, the chemistry of the soil or its physical characteristics, or whether there is interaction between the two. This is the first study to present evidence for soil/plant variation within a serpentine site. The linking of sodium levels to racial differentiation within the serpentine habitat is also a new discovery.

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This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machines or similar means, and storage in data banks. This book is dedicated to:Arthur Cronquist Outstanding plant systematist and major contributor to understanding taxonomic relationships within Asteraceae and Ralph E. Alston (1925Alston ( -1967) Visionary natural products chemist and geneticist who pioneered the use of chemical data in studies of plant systematics and evolution PrefaceCertainly many of the readers of this book will remember the early developments of chemosystematics in the late 1950s. We ourselves remember the excitement of these new data bearing on plant interrelationships. The hopes were high, the techniques were rapidly evolving, the quantities of data were large, and young workers were eagerly enthusiastic. Some even went so far as to predict that chemical data would soon replace morphological information as the basis for plant classification. These overly zealous predictions did not materialize, of course, as the history of plant systematics has amply shown during the past two centuries. If there is any distinct characteristic of systematics it is synthesis, as Lincoln Constance (1964) called it, the "unending synthesis." New tools generate new data and provide insights on additional dimensions of plant relationships. This will never change-we will continue to discover new tools and new data in the years ahead, and they will continue to be incorporated into the predictive general reference system of classification.The earlier efforts in chemosystematics focused on secondary plant products: alkaloids, betacyanins, carbohydrates, cyanogenic glycosides, glucosinolates, lipids, terpenoids, and especialiy flavonoids. The latter were particularly well suited for chemosystematic investigation for several reasons: ease of isolation and characterization, small amounts of plant material needed for analysis, stability of compounds especially through routine preparation of herbarium specimens, and low cost to obtain useful information. As a result of these considerable advantages, literally thousands of studies on use of flavonoids in plant systematics have been published. Although now with the present zest for macromolecular data from DNA restriction sites and sequences, there are fewer workers and laboratories dedicated to flavonoid chemosystematic studies; twenty years ago they were the new currency of exciting data in plant systematics.Because of many workers historically interested in the sunflower family, Asteraceae (or Compositae), in part due to its large size (approximately 23,000 species;Bremer, 1994), and because hundreds of flavonoid compounds were discovered in this family, many chemosystematic investigations have been completed on various taxa. Many studies came from the laboratories of R. A. Alston, B. L. Turner, and T. J. Mabry in the Department of Botany ...

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Summary• Sodium, potassium, calcium, and magnesium ion uptake physiology and tolerance to sodium and magnesium were characterized in two edaphic races (A and C) of two closely related species in the Lasthenia californica complex.• Uptake rates of race A plants were 20-fold higher for Na + , and 2-fold higher for Ca 2+ and Mg 2+ than those of race C plants. Race A translocated c. 50% of absorbed Na + to the shoot compared with < 30% in race C. For Ca 2+ and Mg 2+ corresponding values for the two races were > 95% and ≤ 50%, respectively.• Germination, root growth and survivorship estimates indicated greater tolerance by race A to Na + and Mg 2+ . Significant genotype treatment interactions were observed, suggesting that these races are genetically differentiated in their tolerance responses.• The study suggests parallel evolution of physiological traits in populations belonging to the two species and points to intriguing correlations between the presence of sulfated flavonoids and the capacities for the uptake of and tolerance to specific ions.

Lasthenia californica sensu Ornduff consists of two races that differ in their flavonoid pigments and edaphic tolerances. Recent phylogenetic studies of Lasthenia have revealed that members of L. californica sensu Ornduff belong to two phylogenetic species. The relationship of the edaphic races to these new species and to each other is the focus of this study. Characterization of flavonoid profiles and phylogenetic placement of 33 populations demonstrates that races and phylogenetic taxa are not concordant, suggesting that one or both edaphic races evolved in parallel in the two clades. We hypothesize an edaphically linked ecological role for flavonoid differences that first revealed the existence of two races.

Two edaphic races of Lasthenia californica sensu Ornduff (races A and C) grow in parapatry on a serpentine outcrop at Jasper Ridge Biological Preserve, California. The races occupy distinct edaphic habitats that have different water-holding capacities. We predict that the two races will show differentiation in reproductive strategies related to their response to water stress. In order to test this hypothesis, we performed a greenhouse experiment to characterize the reaction norms of the two races exposed to a gradient in water availability. We measured the response of five variables to the watering treatments: early survivorship, days to flowering, root/shoot dry mass ratio, total dry mass, and a measure of reproductive fitness, number of flower heads. We found that the races differ in their allocation patterns to roots compared with shoots and in days to flowering, indicating genetic differentiation for these traits. Race A consistently allocates relatively more biomass to roots while race C flowers earlier. However, the reaction norms of the two races for all nonreproductive traits are parallel, indicating that races do not differ in their plastic response to drought stress. The number of flower heads, our measure of reproductive fitness, did, however, exhibit differential response to water availability between the two races. Under low watering treatment, race C plants are able to maintain flower head production, while race A plants show a monotonic decrease in head production as water stress increases. Results indicate that race C plants are better adapted to drought; they are able to maintain a high reproductive output under low water availability. However, as the phenotype of race A is affected by drought, reproductive output decreases, as we would predict for plants that rarely experience drought in their natural environment.

Proanthocyanidin (PA) polymers (condensed tannins) were extracted from sainfoin leaves (Onobrychis viciifolia Scop.) at different stages of plant development. Analysis of the phloroglucinol degradation products by high-performance liquid chromatography showed that catechin, epicatechin, gallocatechin, and epigallocatechin were present as terminal units at all stages, while gallocatechin and epigallocatechin were the predominant extension units with lesser amounts of epicatechin incorporated at early stages. Catechin was not incorporated as an extension unit. The number-average molecular weight and degree of polymerization increased with leaf development. There was a very distinct change in the isomerization and degree of hydroxylation of the polymer constituents with development. The composition of ct'sisomers decreased from 83 to 48% and the proportion of trihydroxylated B-rings increased from 60 to 90% with increasing leaf maturity.