Asparagus is a popular vegetable rich in healthy functional components. Asparagus spears are known to contain a large amount of rutin, which has been found to possess anti-inflammatory, antitumor, and antibacterial/viral properties, and protodioscin, which is an antitumor substance and present in the bottom parts (8 cm from the cut end). However, the process of its production leaves fern in the aboveground parts and roots in the underground parts as significant amounts of nonusable parts, and this issue should be solved. This study was conducted to examine the distributions of rutin and protodioscin, representative functional components in different parts of asparagus. The results suggested that large amounts of rutin were noted in the cladophylls and storage roots (brown and epidermis), and the protodioscin content was high in the buds, the soil-covered section of the spear, and the rhizome. A significant amount of rutin was detected in the aboveground parts, which is consistent with the results of previous studies, but it was also found in the storage roots. The largest amount of protodioscin was found in the buds, as well as in young fruits and seeds of the aboveground parts. Injury by continuously cropping asparagus may be associated with high rutin content in the storage roots of asparagus.

Asparagus is a popular vegetable rich in healthy functional components. However, the process of its production leaves ferns from aboveground parts and roots from underground parts as unusable parts, and this is an issue to be resolved. In our previous studies, large amounts of rutin were noted in the cladophylls and storage roots (brown and epidermis), and the protodioscin content was high in buds, in the soil-covered section of spears, and in rhizomes. This study was conducted to examine the distribution of growth-inhibitory activity and mineral contents in different parts of asparagus. Correlations, including representative functional components (rutin and protodioscin), were examined. The results suggest there are differences in growth-inhibitory activity of different parts of asparagus. The growth-inhibitory activity was strong in the buds, rhizome, and absorptive and storage roots, and weak in the cladophylls and lateral branches. The percent N content of the aboveground part of asparagus was high compared with that in the aboveground part of other crops. Although the percent K content was similar to the mean of the aboveground part of other crops, it was higher than that in general green manure, suggesting the residual stems and leaves of the aboveground part of asparagus are effective green manure. In the aboveground part of asparagus, the rutin content and percent N and K content were higher, whereas growth-inhibitory activity tended to be low, suggesting that when no disease developed in the aboveground part, it can be used as an organic substance.

The whole harvest cultivation method for one-year-old plants (new cultivation method) is a labor-saving open field asparagus cultivation method that allows growers to produce a high yield of high-quality asparagus at low-cost. Green and purple asparagus production by the new cultivation method is becoming popular in Japan. White asparagus production in Japan is usually based on blanching with soil (SOIL). On the other hand, the film-cover method (FILM) has also become popular in recent years. In this study, for the purpose of introducing the new cultivation method for white asparagus production, green and purple asparagus were examined regarding the effects of blanching and its methods on the yield and quality of spears. The test was conducted both in Nagano and Kanagawa (cold and warm areas, respectively). The yield and rate of thick spears (L or larger size) cultivated by SOIL and FILM in both cold and warm areas were equivalent to or higher than without blanching (WITHOUT BLANCHING). The amount of rutin in spears cultivated by WITHOUT BLANCHING was significantly higher than by SOIL and FILM. The amount of protodioscin in spears cultivated by SOIL was significantly higher than WITHOUT BLANCHING and FILM. From these results, on using green and purple asparagus blanched by SOIL and FILM to cultivate as white asparagus with the new cultivation method, the quality of spears was different from WITHOUT BLANCHING, and the yield and rate of thick spears were equal or higher.

No abstract