Résumé
Although consecutive monoculture problems have been studied for many years, no effective treatments are currently available. The complexity of systems triggered the formation of consecutive monoculture problems was one major cause. This paper elaborated the physiological and ecological mechanisms of consecutive monoculture problem formation based on the interaction relationship among multiple factors presented in the rhizosphere soil of consecutive monoculture plants. At same time, in this paper the multiple interactions among cultivated medicinal plants, autotoxic allelochemicals and rhizosphere microbial were proposed to be most important causes that derived the formation of consecutive monoculture problem. The paper also highlighted the advantage of 'omics' technologies integrating plant functional genomics and metabolomics as well as microbial macro-omics in understanding the multiple factor interaction under a particular ecological environment. Additionally, taking R. glutinosa as an example, the paper reviewed the molecular mechanism for the formation of R. glutinosa consecutive monoculture problem from the perspective of the accumulation of allelopathic autotoxins, the rhizosphere microecology catastrophe and theresponding of consecutive monoculture plants. Simultaneously, the roles of mutilple 'omics' technologies in comprehending these formation mechanism were described in detail. This paper provides finally a new insight to solve systematically the mechanism of consecutive monoculture problem formation on molecular level.
Résumé
The aim of the present study was to evaluate the effect of soil characteristics (pH, macro- and micro-nutrients), environmental factors (temperature, humidity, period of the year and time of day of collection) and meteorological conditions (rain, sun, cloud and cloud/rain) on the flavonoid content of leaves of Passiflora incarnata L., Passifloraceae. The total flavonoid contents of leaf samples harvested from plants cultivated or collected under different conditions were quantified by high-performance liquid chromatography with ultraviolet detection (HPLC-UV/PAD). Chemometric treatment of the data by principal component (PCA) and hierarchic cluster analyses (HCA) showed that the samples did not present a specific classification in relation to the environmental and soil variables studied, and that the environmental variables were not significant in describing the data set. However, the levels of the elements Fe, B and Cu present in the soil showed an inverse correlation with the total flavonoid contents of the leaves of P. incarnata.
O objetivo deste trabalho foi avaliar os efeitos do solo (pH, macro e micronutrientes), fatores ambientais (temperatura, umidade, época do ano e período da coleta) e condições meteorológicas (chuva, sol, nublado, nublado com chuva) no teor de flavonoides das folhas de Passiflora incarnata L. (Passifloraceae), através do tratamento quimiométrico dos dados por PCA (análise de componentes principais) e HCA (análise hierárquica de agrupamentos). Os flavonoides totais foram quantificados por cromatografia líquida de alta eficiência-detecção por ultravioleta (CLAE-UV/DAD). As análises por PCA e HCA mostraram que as amostras de Passiflora não apresentam uma classificação específica em relação às variáveis estudadas e que as variáveis do meio ambiente não são relevantes para descrever o modelo estudado, porém os elementos do solo Fe, B e Cu demonstraram correlação inversa à concentração dos flavonoides totais.