[Study on winter dormancy of Thesium chinense and its phenological phase].

In order to explore reasonable artificial cultivation pattern of Thesium chinense, the biological characteristics and nutrients change in the process of winter dormancy of T. chinense was studied. The phenological period of T. chinense was observed by using fixed-point notation and the starch grains changes were determined dynamically by PAS-vanadium iron hematoxylin staixjing method. Soluble sugar and starch content were measured by anthrone-sulfuric acid method and amylase activity was determined by DN'S method. The results showed that the normal life cycle of T. chinense was two years. T. chinense was growing by seed in the first year, but growing by the root neck bud in the second year. During the process of dormancy, starch and soluble sugar could mutual transformation in different periods. T. chinense had sufficient carbohydrate to maintain growth and also a lot of small molecules to improve their ability to fight against adversity.

[Complex evaluation for influence of hosts on hemipatasite Thesium chinense].

OBJECTIVE: To study the influence of host species on growth and development and active component content of Thesium chinense. METHOD: Plant morphology and active component content of T. chinense grown with different hosts were measured. The hosts were evaluated by using index-sum method. RESULT: Hosts significantly promoted the growth of T. chinense by increasing height, per plant weight, stem diameter, leaf area, the number of seed and haustorium,and decreased RW/SW ratio compared to without host treatment. Considerable differences existed among the effect of different host species treatments. Synthetical evaluation score of Gnaphlium affine was the highest (37), followed by Imperata cylindrical and Prunella vulgaris (36). It is suggested that they were superior hosts for T. chinense. But the scores of Triticum aestivum (25) and Eremochloa ophiuroides (17) were lower, so they were unsuited hosts for T. chinense. CONCLUSION: Hosts significantly promoted the growth of T. chinense. Considerable differences existed among the growth and development of T. chinense grown with different hosts, as well as active component content. Gnaphlium affine, Imperata cylindrical and Prunella vulgaris were superior hosts for T. chinense. While Triticum aestivum and Eremochloa ophiuroides were unsuited hosts for T. chinense.

[Study on biological characteristics of Thesium chinense].

OBJECTIVE: To study the biological and growth characteristics of Thesium chinense. METHOD: The wild population was observed in certain sites, pot and indoor experiments were applied for cultivated plant. RESULT AND CONCLUSION: T. chinense is an obligate root hemiparasite and perennial herb, stem and leaf were green, there were haustoriums on its root, can only achieve its whole life process when parasitized to host. T. chinense grows mostly in the humid wasteland and herbaceous community where water is generally abundant. T. chinense likes light, warm climate and acidic to neuter soil. The seeds of T. chinense have dormancy characteristics. The life history of T. chinense can divide into 5 stages: seedling, ramify, florescence, fructification and withering periods.

[Pollen dispersion and reproductive success of four tree species of a xerophytic forest from Argentina]. / Dispersión polínica y éxito reproductive de cuatro especies arbóreas de un bosque xerófito de Argentina.

The "talares" in eastern Buenos Aires province, Argentina, are coastal xerophitic forests structured by few arboreal species surrounded by a lower and moister soil matrix. We studied the reproductive parameters of the most representative arboreal species (Celtis tala, Scutia buxifolia, Jodina rhombifolia, and Schinus longifolia). Pollen dispersion was studied through floral visitor traps (biotic dispersion) and using gravimetric pollen collectors (abiotic dispersion). The reproductive success (fruit formation rate) of the focal species was studied by enclosing flowers with different mesh bags. The reproductive system varied among the different species. C. tala was anemophilous and selfcompatible. S. buxifolia was entomophilous and floral visitors dependant. J. rhombifolia was entomophylous, although spontaneous autogamy could favor reproduction in the absence of pollinators. Lastly, S. longifolia could be an ambophilous species (pollinated by insects and by the wind). This dual system may be the result of system flexibility mechanism or an evolutionary transition.

Dispersión polínica y éxito reproductivo de cuatro especies arbóreas de un bosque xerófito de Argentina

Pollen dispersion and reproductive success of four tree species of a xerophytic forest from Argentina. The "talares" in eastern Buenos Aires province, Argentina, are coastal xerophitic forests structured by few arboreal species surrounded by a lower and moister soil matrix. We studied the reproductive parameters of the most representative arboreal species (Celtis tala, Scutia buxifolia, Jodina rhombifolia,and Schinus longifolia). Pollen dispersion was studied through floral visitor traps (biotic dispersion) and using gravimetric pollen collectors (abiotic dispersion). The reproductive success (fruit formation rate) of the focal species was studied by enclosing flowers with different mesh bags. The reproductive system varied among the different species. C. tala was anemophilous and selfcompatible. S. buxifolia was entomophilous and floral visitors dependant. J. rhombifolia was entomophylous, although spontaneous autogamy could favor reproduction in the absence of pollinators. Lastly, S. longifolia could be an ambophilous species (pollinated by insects and by the wind). This dual system may be the result of system flexibility mechanism or an evolutionary transition. Rev. Biol. Trop. 57 (1-2): 283-292. Epub 2009 June 30.

Los "talares" del E de la provincia de Buenos Aires son bosques xerófitos costeros estructurados por pocas especies arbóreas rodeados de una matriz de suelos más bajos y húmedos. Estudiamos los parámetros reproductivos de las especies arbóreas más representativas (Celtis tala, Scutia buxifolia, Jodina rhombifolia y Schinus longifolia). La dispersión polínica fue estudiada a través de trampas para visitantes florales (dispersión biótica) y utilizando recolectores gravimétricos de polen (dispersión abiótica). El éxito reproductivo (tasa de formación de frutos) de las especies focales fue estudiado a través de embolsado de flores con bolsas de distintos tipos de malla. El sistema reproductivo varió entre las especies. C. tala resultó anemófila y autocompatible, S. buxifolia fue entomófila y dependiente de los visitantes florales. J. rhombifolia fue una especie entomófila, aunque la autogamia espontánea podría favorecer al aseguramiento reproductivo en caso de falta de polinizadores. Finalmente, S. longifolia podría ser una especie ambófila (polinizada por insectos y por el viento). Este sistema dual podría ser el resultado de un mecanismo de flexibilidad del sistema de polinización o una transición evolutiva.