The abiotic and biotic drivers of rapid diversification in Andean bellflowers (Campanulaceae)

The tropical Andes of South America, the world's richest biodiversity hotspot, are home to many rapid radiations. While geological, climatic, and ecological processes collectively explain such radiations, their relative contributions are seldom examined within a single clade. We explore the contribution of these factors by applying a series of diversification models that incorporate mountain building, climate change, and trait evolution to the first dated phylogeny of Andean bellflowers (Campanulaceae: Lobelioideae). Our framework is novel for its direct incorporation of geological data on Andean uplift into a macroevolutionary model. We show that speciation and extinction are differentially influenced by abiotic factors: speciation rates rose concurrently with Andean elevation, while extinction rates decreased during global cooling. Pollination syndrome and fruit type, both biotic traits known to facilitate mutualisms, played an additional role in driving diversification. These abiotic and biotic factors resulted in one of the fastest radiations reported to date: the centropogonids, whose 550 species arose in the last 5 million yr. Our study represents a significant advance in our understanding of plant evolution in Andean cloud forests. It further highlights the power of combining phylogenetic and Earth science models to explore the interplay of geology, climate, and ecology in generating the world's biodiversity.

Coloration of the Chilean Bellflower, Nolana paradoxa, interpreted with a scattering and absorbing layer stack model

An absorbing-layer-stack model allows quantitative analysis of the light flux in flowers and the resulting reflectance spectra. It provides insight in how plants can optimize their flower coloration for attracting pollinators. The coloration of flowers is due to the combined effect of pigments and light-scattering structures. To interpret flower coloration, we applied an optical model that considers a flower as a stack of layers, where each layer can be treated with the Kubelka-Munk theory for diffusely scattering and absorbing media. We applied our model to the flowers of the Chilean Bellflower, Nolana paradoxa, which have distinctly different-colored adaxial and abaxial sides. We found that the flowers have a pigmented, strongly scattering upper layer, in combination with an unpigmented, moderately reflecting lower layer. The model allowed quantitative interpretation of the reflectance and transmittance spectra measured with an integrating sphere. The absorbance spectrum of the pigment measured with a microspectrophotometer confirmed the spectrum derived by modeling. We discuss how different pigment localizations yield different reflectance spectra. The absorbing layer stack model aids in understanding the various constraints and options for plants to tune their coloration.

Genomic instability in phenotypically normal regenerants of medicinal plant Codonopsis lanceolata Benth. et Hook. f., as revealed by ISSR and RAPD markers

Codonopsis lanceolata Benth. et Hook. f., commonly known as bonnet bellflower, is a high-valued herb medicine and vegetable. In this study, a large number of plants were regenerated via organogenesis from immature seed-derived calli in C. lanceolata by a simple and efficient method. Compared with the mother donor plant, the regenerated plants did not exhibit visible phenotypic variations in six major morphological traits examined at the stage of one-season-maturity under field conditions. To gain insight into the genomic stability of these regenerated plants, 63 individuals were randomly tagged among a population of more than 2,000 regenerants, and were compared with the single mother donor plant by two molecular markers, the inter-simple sequence repeats (ISSR) and randomly amplified polymorphic DNA (RAPD). Apparent genomic variation was detected in the 63 regenerants, whereas preexisting heterozygosiy in the donor plant was deemed minimal by testing 30 seedlings germinated from selfed seeds of the same donor plant. The percentages of polymorphic bands (PPB) in the ISSR and RAPD analysis were respectively 15.7 and 24.9% for the 63 regenerated plants. Cluster analysis indicates that the genetic similarity values calculated on the basis of RAPD and ISSR data among the 64 plants (63 regenerated and one donor) were respectively 0.894 and 0.933, which allow classification of the plants into distinct groups. Nineteen randomly isolated bands underlying the changed RAPD or ISSR patterns were sequenced, and three of them showed significant homology to known-function genes. Detailed pairwise sequence comparison at one locus between the donor plant and a regenerant revealed that insertion of two short (24 and 19 bp) stretches of nucleotides in the regenerated plant relative to the donor plant occurred in an apparently stochastic manner.

[Study on dynamic growth of Codonopsis pilosula]

OBJECTIVE

To study on the dynamic changes of Codnopsis pilosula for the guidance of the field management.

METHOD

Using the random method the influences of the cultivating density and fertilizing weight at four different levels was observed.

RESULT AND CONCLUSION

The dynamic changes of the biomass, growth period andbiological changes at different growth stages were found out. The most predominant combination of the two factors, the 1.05 million roots/hm2 of the cultivating density and 240 kg x hm(-2) of the fertilizing weight reached the highest accumulation of stems & leaves; 652 mg x d(-1) the 0.6 million roots/hm2 and 240 kg x hm(-2) reached the heaviest single fresh root. The results could be used for the cultivating, fertilizing and practicing SOP of C. pilosula.

[Study on biomass dynamic changes of Codnopsis pilosula under the planting density and fertilizing amount]

Study on the biomass dynamic changes of Codnopsis pilosula (Franch.) Naff. under the different planting density and fertilizing amount of the four levels respectively via the random methods have showed out: the best combination for the stems and leaves are 1.05 million plant/hm2 and 240 kg fertilizer/hm2. Its biomass accumulation can achieve 652 mg/d; That for the root are 0.6 million plant/hm2 and 240 kg fertilizer/hm2 and the weight of every fresh root achieved 14. 88g. The results will be helpful to cultivating and fertilizing of Codnopsis pilosula.

[The effects of fertilization on yield and root diameter of Codonopsis pilosula var. modesla]

Field trials were conducted using three factors regression design of quadratic orthogonal rotation. The result indicated that under the condition of cultivation, yield and average root diameter of Codonopsis Pilosula var. modesla (Nannf) L.T. Shen showed a positive correlation with N fertilizer application on high fertilization level; The effect of major three fertilizer on yield and average diameter of root was K > P > N. In the course of selective optimization yield which is higher than 3750 kg/hm2 (fresh weight) and average diameter of root which is more than 1.5 cm, the index of fertilizer application for N, P and K pure nutrient is 155 kg/hm2, 250 kg/hm2 (P2O5) and 60 kg/hm2 (K2O) respectively. The ration of N:P:K is 1:1.6:0.4.