GENERAL EVALUATION 



333 



Chemical races of Acorus calamus have been described 

 (Wulff and Stahl, 1960). This species is composed of diploid, tri- 

 ploid, and tetraploid races. Analysis of these cytologically different 

 populations from various locations showed significant differences in 

 their essential oil contents (Fig. 16-3). The most striking differences 

 were found between diploid and polyploid races. Two widely 

 separated diploids (from Canada and Denmark) were virtually 

 identical in their oil content, containing mostly geranyl acetate. 

 Triploids from various European sources showed similar patterns: no 

 geranyl acetate but a high content of asarone and traces of iso- 

 eugenol methyl ester. The tetraploids contained slightly less asarone 

 and more isoeugenol methyl ester. It is not clear from this work 

 whether the biochemical differences were the direct result of the 

 cytological differences or the result of genetic selection subsequent to 

 the formation of the cytological races. 



A rather similar situation involving the mustard oils of 

 Brassica Juncea seeds has been reported by Hemingway et al. (1961). 

 Seed samples of ninety-six individuals were collected from different 

 parts of the world, grown in England, and analyzed for their mustard 

 oil content. It was found that these samples could be arranged into 



Rf 

 1,0 



0,8 



0,6 



0,4 



0,2 







2n 2n 3n 4n 4n 



Montreal Kopenh. Kiel Leningr. "pana' 



u u u u u 



Test 



□:n 



:□ 



CZIZCZI 



n:n 



\^ 



CZl 



V77771. '7Z!Zi}[ 



□:n 



czi: 



c=i:iiii 



□:□ 



□: 



n: 



en 



DP 



\ 



□:□ 



□:□ 



□: 



□a 



o 



O - 



Fig. 16-3. Schematic representation of essential oils of several 

 cultivars oi Acorus calamus, u = upper half of leaves; o = lower 

 half of leaves. ^= geranylacetate; \^= asarone; ^= isoeugenol- 

 methylether. (After Wulff and Stahl, 1960). 



