caa a22 4500 469097477 CHVBK 20180323133035.0 cr unu---uuuuu 170328e19920801xx s 000 0 eng 10.1007/BF00317253 doi (NATIONALLICENCE)springer-10.1007/BF00317253 Physiological and growth responses of Centaurea maculosa (Asteraceae) to root herbivory under varying levels of interspecific plant competition and soil nitrogen availability [Elektronische Daten] [Thomas Steinger, Heinz Müller-Schärer] Summary: Centaurea maculosa seedlings were grown in pots to study the effects of root herbivory by Agapeta zoegana L. (Lep.: Cochylidae) and Cyphocleonus achates Fahr. (Col.: Curculionidae), grass competition and nitrogen shortage (each present or absent), using a full factorial design. The aims of the study were to analyse the impact of root herbivory on plant growth, resource allocation and physiological processes, and to test if these plant responses to herbivory were influenced by plant competition and nitrogen availability. The two root herbivores differed markedly in their impact on plant growth. While feeding by the moth A. zoegana in the root cortex had no effect on shoot and root mass, feeding by the weevil C. achates in the central vascular tissue greatly reduced shoot mass, but not root mass, leading to a reduced shoot/root ratio. The absence of significant effects of the two herbivores on root biomass, despite considerable consumption, indicates that compensatory root growth occurred. Competition with grass affected plant growth more than herbivory and nutrient status, resulting in reduced shoot and root growth, and number of leaves. Nitrogen shortage did not affect plant growth directly but greatly influenced the compensatory capacity of Centaurea maculosa to root herbivory. Under high nitrogen conditions, shoot biomass of plants infested by the weevil was reduced by 30% compared with uninfested plants. However, under poor nitrogen conditions a 63% reduction was observed compared with corresponding controls. Root herbivory was the most important stress factor affecting plant physiology. Besides a relative increase in biomass allocation to the roots, infested plants also showed a significant increase in nitrogen concentration in the roots and a concomitant reduction in leaf nitrogen concentration, reflecting a redirection of the nitrogen to the stronger sink. The level of fructans was greatly reduced in the roots after herbivore feeding. This is thought to be a consequence of their mobilisation to support compensatory root growth. A preliminary model linking the effects of these root herbivores to the physiological processes of C. maculosa is presented. Springer-Verlag, 1992 Insect root herbivory nationallicence Resource allocation nationallicence Centaurea maculosa nationallicence Compensatory responses nationallicence Plant competition nationallicence Steinger Thomas Botanical Institute, University of Basel, Hebelstrasse 1, CH-4056, Basel, Switzerland aut Müller-Schärer Heinz Zoological Institute, University of Basel, Rheinsprung 9, CH-4051, Basel, Switzerland aut Oecologia Springer-Verlag 91/1(1992-08-01), 141-149 0029-8549 91:1<141 1992 91 442 https://doi.org/10.1007/BF00317253 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00317253 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Steinger Thomas Botanical Institute, University of Basel, Hebelstrasse 1, CH-4056, Basel, Switzerland aut NATIONALLICENCE 700 1- Müller-Schärer Heinz Zoological Institute, University of Basel, Rheinsprung 9, CH-4051, Basel, Switzerland aut NATIONALLICENCE 773 0- Oecologia Springer-Verlag 91/1(1992-08-01), 141-149 0029-8549 91:1<141 1992 91 442 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer