Aphid (Sitobion yakini) investigation shows thin-walled sieve tubes in barley (Hordeum vulgare L) to be more functional than thick-walled sieve tubes.

Matsiliza, B. and Botha, C.E.J. (2002) Aphid (Sitobion yakini) investigation shows thin-walled sieve tubes in barley (Hordeum vulgare L) to be more functional than thick-walled sieve tubes. Physiologia Plantarum, 115 (1). pp. 137-143. ISSN 0031-9317

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Abstract

Barley, like most other grasses that have been studied, contains two kinds of sieve tube. The first formed are called thinwalled sieve tubes because of their thin wall compared to the late-formed, and are associated with companion cells. The late-formed are thick-walled sieve tubes, which differentiate next to the metaxylem vessels and lack companion cells. Aphid (Sitobion yakini (Eastop) feeding was studied using light microscopy to determine if they preferentially feed from thin- or thick-walled sieve tubes in the barley leaf. Penetration of the stylets through the leaf epidermis and mesophyll was largely intercellular, becoming partly intercellular and, partly, intracellular inside the vascular bundle. Sixteen of 19 pairs of stylets (84%), and 293 of 317 (92%) stylet tracks terminated at the thin-walled sieve tubes, suggesting that Sitobion yakini feeds preferentially on the thin-walled sieve tubes which seem to be more attractive to the aphid. These thin-walled sieve tubes are thus probably the most functional in terms of phloem loading and transport.

Item Type:Article
Additional Information:The definitive version is available at www.blackwell-synergy.com
Uncontrolled Keywords:Phloem function; thin-walled sieve tube; thick-walled sieve tube; Aphid; barley; Sitobion yakini
Subjects:Y Unknown > Subjects to be assigned
Divisions:Faculty > Faculty of Science > Botany
ID Code:322
Deposited By: Ms Vivien Botha
Deposited On:05 Sep 2006
Last Modified:06 Jan 2012 16:17
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