^a*Seyed M. Hosseini, ^aDavid Kartoolinejad, ^aS.K. Mirnia,

^bZ. Tabibzadeh, ^aM. Akbarinia and ^aF. Shayanmehr

*Associate Professor

^aTarbiat Modares University. Natural Resource Faculty. Department of Forestry. Nour, Mazandaran, P.O. Box 46414-356, IRAN

^bTarbiat Modares University. Agriculture Faculty. Department ofSoil Science. IRAN

Abstract. For investigation of the mistletoe (Viscom album L.) effects on leaf area and weight of the host trees, a number of severely infected individuals and completely healthy trees (control trees) were studied. The area and weight of the eleven largest leaves of branches were collected and measured accurately. Moreover, for comparison of nutritional status, several healthy and infected Hornbeam Carpinus betulus and Ironwood Parrotia persica species individuals, with approximately similar conditions of DBH, height and other outward features were selected. Almost 100 leaves from parasitized and unparasitized branches of two host species were sampled in order to compare with control trees (uninfected trees near each host). Results showed, the area of leaves and weight of parasitized branches were less than unparasitized branches and control trees in 95% confidence level. Furthermore the amount of mineral nutrients of K, Mn and Zn showed the higher level in parasitized branches compared to control trees; in contrast, the quantity of nitrogen just in Iron wood host species was lower. This paper suggests, the V. album L. may have undesirable and displeasing effects on leaf structure, physiological and nutritional status of host trees in high intensity of infections.

Key words: Mistletoe; ironwood species; host trees; nutritional status; leaf area

Efeitos do Visco Europeu nas Folhas e Elementos Nutritivos de Duas Espécies Hospedeiras das Florestas da Hircânia

Sumário. Para investigar os efeitos do visco na área foliar e peso das árvores hospedeiras, estudaram-se indivíduos severamente afectados e totalmente sãos (testemunha). Colheram-se as onze maiores folhas dos ramos e registou-se cuidadosamente a área foliar e o peso. Além disso, para comparação do teor de nutrientes, seleccionaram-se algumas espécies afectadas e algumas sãs, de Carpinus betulus e Parrotia persica, com semelhante DAP, altura e outras características externas. Amostraram-se cerca de 100 folhas de ramos de árvores parasitadas e não parasitadas, para comparação com as árvores testemunha (árvores sãs próximo de cada hospedeira). Os resultados demonstraram que a área e o peso das folhas de ramos atacados era inferior ao verificado para os de ramos não parasitados e árvores testemunha, para um nível de confiança de 95%. Também o nível de nutrientes minerais K, Mn e Zn foi mais elevado em ramos atacados em comparação com as árvores testemunha; pelo contrário, o teor de nitrogénio em Parrotia persica foi inferior. Este trabalho sugere que V. album L. pode provocar efeitos indesejáveis na estrutura da folha, na fisiologia e no teor de nutrientes das hospedeiras com elevada intensidade de infecção.

Palavras-chave: Visco; hospedeiras; espécies de pau-ferro; teor de nutrientes; área foliar

Effet du Gui d'Européen sur les Feuilles et les Éléments Alimentaires de Deux Espèces Hôtes Dans les Forêts Hyrcaniennes

Résumé. Pour la recherche des effets du gui sur la surface foliaire et le poids des arbres hôtes, un certain nombre d'individus sévèrement infectés et d'autres complètement sains (arbres témoins) ont été étudiés. La surface et le poids des onze plus grandes feuilles des branches ont été recueillis et mesurés avec précision. Par ailleurs, pour la comparaison du statut alimentaire, plusieurs individus d'espèces saines et infectées de Hornbeam et d'Ironwood, avec des DBH approximativement semblables, la taille et d'autres caractéristiques extérieures ont été choisis. Presque 100 feuilles des branches parasitées et parasitées de deux espèces hôtes ont été prélevées afin de les comparer avec les arbres témoins (arbres non infectés près de chaque hôte). Les résultats ont montré que la surface des feuilles et le poids des branches parasitées étaient moindre que ceux des branches non parasitées ainsi que des arbres témoins, pour un taux de confiance de 95%. En outre la quantité d'aliments minéraux en K, Mn et  Zn a montré de plus hauts niveaux dans les branches parasitées comparées aux arbres témoins; mais en revanche, la quantité d'azote, pour Parrotia persica était inférieure. Ce document suggère que, V. album L. peut exercer des effets indésirables et contrariants sur la structure de la feuille, la physiologie et l'alimentation des arbres de l'hôte dans une forte intensité d'infection.

Mots clés: Gui; espèces d'Ironwood; arbres hôtes; statut alimentaire; région de feuille

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Entregue para publicação em Fevereiro 2007

Aceite para publicação em Julho 2008

^* Corresponding Author E-mail: hosseini@modares.ac.ir