ISSN:
1615-6110
Keywords:
Angiosperms
;
Scrophulariaceae
;
Orobanchaceae
;
Lesquereuxia = Siphonostegia syriaca
;
Parasitism
;
secondary haustoria
;
primary haustorium
;
apical meristem
;
evolution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In the parasiticScrophulariaceae andOrobanchaceae, two types of contact organs exist: secondary and primary haustoria. Secondary haustoria are lateral organs, developing in large numbers and only when the seedling is fully established. In contrast, a primary haustorium represents the first developmental stage of the seedling itself. In the root system of the parasiticLesquereuxia syriaca (=Siphonostegia syriaca) there are only secondary haustoria, but a few of them apparently develop in a terminal position. This is achieved by transferring the haustorial initiation region closer to the root apex. One can interpret this as a transformation of the apical meristem into a meristematic haustorial tissue. On the condition that an extreme shortening (abbrevation) of the primary root could happen, we discuss the transformation of the terminal secondary into a primary haustorium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00936067
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