[Influence of storage conditions on the seed development of Corydalis yanhusuo]

OBJECTIVE

To explore the influence of the storage conditions on the seed development of Corydalis yanhusuo.

METHODS

The embryo formation process of the wild Corydalis yanhusuo was observed,and the germination rate of wild Corydalis yanhusuo seeds stored under different conditions was measured.

RESULTS

The seed development of the wild Corydalis yanhusuo depended on the storage conditions. The seeds subjected to stratification had the highest germination percentage. Those stored in dry conditions would lose the vitality completely. The seeds in isothermal storage had very low germination rates. As revealed by slices, only the seeds after stratification treatment had the ability to form a complete embryo.

CONCLUSION

The Corydalis yanhusuo seed is a kind of seed without fully developed embryo, and needs further after-ripening for its development. Its vitality has a great seasonal and annual dependence.

Bud development in corydalis (Corydalis bracteata) requires low temperature: a study of developmental and carbohydrate changes

BACKGROUND AND AIMS

Spring geophytes require a period of low temperature for proper flower development but the mechanism that underlies the relationship between cold treatment and flowering remains unknown. The present study aims to compare the developmental anatomy and carbohydrate content of the tuberous geophyte Corydalis bracteata growing under natural winter conditions from 10 to -10 degrees C (field-grown) and under a mild temperature regime of 18 degrees C (indoor-grown plants).

METHODS

Samples were studied under light and electron microscopy. A histochemical test (periodic acid--Schiff's) was employed to identify starch in sectioned material. Sugars were analysed by capillary gas chromatography. Apoplastic wash fluid was prepared.

KEY RESULTS

Under natural conditions, shoots were elongated, and buds gained in dry mass and developed normally. For indoor-grown plants, these parameters were lower in value and, from December, a progressive necrosis of flower buds was observed. The tuber consisted of the new developing one, which was connected to the bud, and the old tuber with its starch reserve. Due to the absence of plasmodesmata between new and old tuber cells, sugar transport cannot be through the symplast. Thus, a potential apoplastic route is proposed from old tuber phloem parenchyma cells to the adjacent new tuber cells. Sugar content in buds during the autumn months (September-November) was lower for indoor-grown plants than control plants, whereas the sugar content in tubers during the same period was similar for plants from both temperature treatments. However, the amount of apoplastic sugars in tubers of field-grown plants was almost 15-fold higher than in indoor-grown tubers.

CONCLUSIONS

The results suggest that low temperature activates the apoplastic route of sugar transport in C. bracteata tubers and a consequent carbohydrate delivery to the bud. In the absence of cold treatment, the carbohydrate reserve is locked in old tuber cells so the nutrient supply to the buds is suppressed, possibly leading to bud abortion.

Temperature conditions control embryo growth and seed germination of Corydalis solida (L.) Clairv., a temperate forest spring geophyte

Spring is often the most suitable period for seedling establishment of temperate woodland species. Different physiological mechanisms resulting in spring emergence have evolved in seeds of such plants. The aim of this study was to determine the requirements for breaking dormancy and for seed germination of the European perennial spring geophyte Corydalis solida (Fumariaceae). Ripe seeds of C. solida contain an underdeveloped embryo, consisting of no more than a clump of cells. As a consequence, the embryo has to differentiate and grow to a critical length before germination can occur. In nature, seeds are dispersed in spring, while growth of the embryo starts in the autumn and continues in winter. Germination starts in late winter, immediately after embryo growth is completed, resulting in seedling emergence in the following spring. Experiments in controlled conditions showed that temperature is the main factor controlling dormancy and germination. Incubation at autumn temperatures (15/6 degrees C; 20/10 degrees C) for at least 8 weeks is required to initiate embryo growth, while a transfer to 5 degrees C is needed for completion of embryo growth and germination. Growth of the embryo of C. solida occurs at different temperatures over an extended period, a feature typical of temperate forest herbs. Our results indicate that the dormancy mechanism in seeds of C. solida is very similar to mechanisms in other Corydalis species studied thus far, suggesting that stasis in the dormancy trait has occurred.

[Study on the influence on Rhizoma Corydalis by different harvest time and processing methods]

OBJECTIVE

To choose the best harvest time and initial processing method of Rhizoma Corydalis.

METHODS

Taking the content of tetrahydropalmatine and dry rates as major indices, different samples from different harvest time and different processing methods were investigated by HPLC. The C18 column (250 mm x 4.6 mm, 5 microm) was used with mobile phase of methanol-0.1% phosphoric acid solution (pH = 6.0, adjusted with triethylamine) (58: 42). The mobile phase flow rate was 1.0 mL/min. The detection wavelength was 280 nm.

RESULTS

The contents of tetrahydropalmatine were similar although the harvest time was different. The dry rate on May 21 was higher than the others. The content of tetrahydropalmatine was the highest by steaming and reached 0.11%.

CONCLUSION

The best harvest time for Rhizoma Corydalis is around 10 days after the above-ground plant wilted, and the best initial processing method for Rhizoma Corydalis is steaming.

Differential effects of nectar robbing by the same bumble-bee species on three sympatric Corydalis species with varied mating systems

BACKGROUND AND AIMS

Most research on the widespread phenomenon of nectar robbing has focused on the effect of the nectar robbers' behaviour on host-plant fitness. However, attention also needs be paid to the characteristics of host plants, which can potentially influence the consequences of nectar robbing as well. A system of three sympatric Corydalis species sharing the same nectar-robbing bumble-bee was therefore studied over 3 years in order to investigate the effect of nectar robbing on host reproductive fitness.

METHODS

Three perennial species of Corydalis were studied in the Shennongjia Mountain area, central China. Observations were conducted on visitor behaviour and visitation frequencies of nectar-robbers and legitimate pollinators.

KEY RESULTS

The results indicated that the effect of nectar robbing by Bombus pyrosoma varied among species, and the three species had different mating systems. Seed set was thus influenced differentially: there was no effect on seed set of the predominantly selfing C. tomentella; for the facultative outcrossing C. incisa, nectar robbing by B. pyrosoma had a positive effect; and nectar robbing had a significant negative effect on the seed set of outcrossing C. ternatifolia.

CONCLUSIONS

A hypothesis is proposed that the type of host-plant mating system could influence the consequences of nectar robbing on host reproductive fitness.

Establishment of callus and cell suspension cultures of Corydalis saxicola Bunting, a rare medicinal plant

An efficient procedure has been developed for callus induction and cell suspension cultures of C. saxicola for the first time. Explant selection was carried out among leaf, stem and root to select a suitable type of explants capable of higher callus formation. Leaf explants thus selected showed maximum response to callus induction (67.1%). Modified B5 medium supplemented with 0.5 mg l(-1) 2,4-D plus 2 mg l(-1) BA was the most favorable medium for callus formation with the highest induction rate (94.8%) and greatest fresh weight of callus (1.7 g per explant). Cell suspension cultures were established by transferring 2-8 g fresh callus to 80 ml liquid B5 medium. An inoculum size of 8 g produced the greatest biomass accumulation, dehydrocavidine and berberine productions, which was 13.1 g l(-1), 8.0 mg l(-1) and 4.1 mg l(-1), respectively. In response to various sucrose concentrations from 10 g l(-1) to 80 g l(-1), cultures with 60 g sucrose l(-1) not only produced the highest dry biomass (18.5 g l(-1)) but also the highest formation of dehydrocavidine (11.6 mg l(-1)) and berberine (7.6 mg l(-1)). These prepared cell suspension cultures provided a useful material for further regulation of alkaloid biosynthesis and for enhanced production of valuable alkaloids on a large scale.

[Studies on morphology and histology of medicinal part of Corydalis yanhusuo]

OBJECTIVE

To Study the morphology, microstructure and morphosis of medicinal part of Corydalis yanhusuo, and provide a basis for the knowledge of the type of modified stem of Corydalis yanhusuo and the identification of crude drug.

METHOD

Sample collection, culture observation and microsectile observation.

RESULT

Morphological and histological characters and morphogenetic and developmental regulation of medicinal part of Corydalis yanhusuo are described with pictures.

CONCLUSION

The medicinal part of Corydalis yanhusuo is bulb, and the conception that the medicinal part of Corydalis yanhusuo is tuber is wrong.