Anatomical Studies on Compatibility and Incompatibility of Some Solanaceous Plant Species to Field Dodder ( Cuscuta campestris Yuncker)

Abstract

Four solanaceous plant species, namely hot pepper (Capsicum frutescens L.), potato (Solanum tuberosum L.), tobacco (Nicotiana tabacum L.) and tomato (Lycopersicon esculentum Miller) were anatomically screened for compatibility/incompatibility to field dodder (Cuscuta campestris Yuncker, Cuscutaceae). The development of field dodder haustorium within stem tissues of the studied solanaceous plants was found to depend on the latter’s response to the former’s penetration. In hot pepper and tobacco, which showed a positive response, the haustorium was well developed and its searching hyphae established connections with their vascular tissues. However, potato and tomato showed a negative response and acquired different defense mechanisms against the parasitism of field dodder. In both of them, the field dodder haustorium and/or its searching hyphae exhibited distorted appearance and failed to establish connection with their vascular tissues. Thus, the tested solanaceous plant species could be classified as either compatible (hot pepper and tobacco) or incompatible (potato and tomato) hosts to field dodder.