Based upon investigations in the areas of Jiangsu province where Atractylodes lancea has been recorded, the authors suggest that it will disappear from these areas in 10 or at most 20 years if commercial collecting continues at its current rate. Reasons for this conclusion are discussed. The results of the investigation indicate that plants from different provenances sometimes have different morphological characteristics, which are genetically determined. But not all provenances can be divided clearly by morphological features. There are different variations on chemical constituents within populations. At least two types of variation have been discovered in Jiangsu province. The proportions of two types are 19% and 51% respectively.
As natural medicines are the best ones for mankind and the use of plant drugs for curing diseases is still the common practice in many developing countries, especially in rural areas, many common, widely-used and traditional medicinal plants are under severe threat and are becoming almost extinct in the areas where people have been collecting them. This situation will lead to the sources of many medicinal plants being exhausted in near future. Atractylodes lancea is one such plant.
The Maoshan Mountains are the growing centre of the traditional and typical product of 'cangzhu', derived from A. lancea, although this plant is distributed widely in central China. The best medicinal material from A. lancea is the so-called 'mao-cangzhu'. This medicine is mainly used for the treatment of indigestion and stomach ache.
Based upon an investigation of the production of cangzhu from A. lancea in five counties - Juroung, Jintan, Lishui, Liyang and Gaochun - in Jiangsu province, it has been found that the highest production was in the 1950s. The record production was 15 000 kg per year in Liyang county. Compared with the production in the 1960s and 1970s, production in the 1980s has been seriously reduced. Resources of A. lancea seem to be exhausted in all five counties in Jiangsu. Actually, the collection of A. lancea has almost stopped (Table 1). The data indicates that the size of the resource sharply reduced as soon as the commercial collecting activity began in the county. It will disappear from these areas in 10 or at most 20 years if commercial collection continues at its current rate, if it is not protected. After about 20 years the area will no longer provide any commercial resources.
The slow rate of growth of the species could be an important factor in such a rapid depletion. According to cultivation experiments, the additional weight-gain of its rhizomes is only two times the weight of the rhizomes which have been planted in the field at the beginning of the season. In other words, when the weight of rhizomes for propagation is 1, the yield harvested is only 3. In 1989, 210 kg of rhizomes were planted in spring in Nanjing and only 639 kg of rhizomes were harvested in autumn. Experimental comparisons of the two kinds of differently-shaped rhizomes have not shown any apparent difference in yield (Table 2). Their weight increases are also around two times or a little more of the propagation material. The slow-growing nature of the plant might be further explained by the weight increment of seedlings from seeds. The weight of rhizomes of one-year old seedlings is only 3.6 g and that of two-year old seedlings is 11.6 g.
Obviously, under natural conditions the slow-growing characteristic is an important reason for this plant's depletion. Thus protection measurement and cultivation are absolutely necessary for Atractylodes.
Although the Maoshan area is the most famous region for cangzhu, A. lancea is distributed widely in the country, including Jiangsu, Zhejiang, Shandong, Anhui, Hubei and Sichuan provinces. The results of investigations in Jiangsu, Anhui and Hubei provinces show that it is distributed from 60 m to 1000 m above sea-level. The sites investigated have relatively similar climatic patterns, but their precipitation is different. This varies from 850 mm to 1560 mm (Table 3). Soils are mostly acidic, about pH 5 and occasionally alkaline, pH 7.5. The rocks are mostly granite and quartzite, as well as limestone (Table 4). A. lancea distribution is always concentrated on northern-facing slopes. From Table 3 it is clear that the climatic conditions in the Yingshan area are relatively different from others, since it is at a relatively high elevation.
The plant communities that include A. lancea contain tree species such as Quercus, Lindera and Verbena, and shrubs and herbaceous plants such as Smilax, Pteridium, Carex, Eulalia, Eupatorium, Rosa, Rubus, Houttuynia and Lysimachia (Table 5). Morphological changes are also apparent in plants grown under different conditions. In order to verify the morphological change caused by genetic variations, samples taken from Nanjing Botanical Garden experimental plots were analyzed. All the samples had been introduced from the original sites and propagated vegetatively. It seems that the differences were due to genetic variations. Plants of different provenances show differences in leaf shape (Fig.1).
Medicinal plants are characterised by the presence of useful or effective components. Plants with similar morphological features grown on the same site may contain different chemical components. The variations within populations are especially important for medicinal plants. Takeda et al (1992) reported the analysis of 144 samples collected from four sites - Juroung-Ya, Jintan-Xu, Liyang-Li, and Nanjing-Fo - in Jiangsu province, and indicated that there are at least two types of variation according to the different chemical constituents (Table 6).
Another feature which should be mentioned is that none of the samples from the Nanjing-Fo site contain selina-4(14), 7(11)-dien-8-one, but samples from all three other sites always contain it.
It was commonly considered (Harada 1989) that atractylon is the characteristic component of A. macrocephala. According to this study most samples of A. lancea collected from Jiangsu, the typical area for this medicinal plant, contain atractylon. It seems that there could be some natural hybrids between species of the genus. If the proposed idea is correct for the recognition of mao changzhu, the typical description for A. lancea should be changed.
Localities: Xu = Maoshan (Jiangsu province), Hu = Taiping (Anhui province), Ta = Yingshan (Hubei province), Ca = Suizhou (Hubei province), Wu = Danjiang (Hubei province).
AMT = Annual mean temperature in oC, XMMT = Maximum monthly mean temperature in oC, IMMT = Minimum monthly mean temperature in oC, AP = Annual precipitation in mm, NFD = No. of non-frost days, SP = Sunshine percentage, ALT = Altitude in m.
Localities as in Table 3. OM = Organic matter, TN = Total nitrogen
Localities as in Table 3.
* 30 % not determined. ATR = Atractylon, HIN = Hinesol, EUD = ß-cudesmol, ATD = Atractylodin.
Fig 1. Leaf shapes of different provenances introduced vegetatively from original distributed areas. Samples collected from living collections for ex situ conservation in Nanjing Botanic Garden in 1992. Location codes as for Table 3.
Harada, M. (1989). Quantitative components of common medicinal drugs. pp. 221-4. Hirokawa Publishing Co. (In Japanese).
Takeda, O. et al. 1992. Variation of essential oil components of Atractylodes lancea DC. growing in Maoshan mountains in Jiangsu province, China. In Proceedings of the 39th Annual Meeting of the Japanese Society of Pharmacognosy.
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