The effect of mealybug Pseudococcus longispinus (Targioni Tozzetti) infestation of different density on physiological responses of Phalaenopsis × hybridum ‘Innocence’

Abstract

Cultivated orchids are the most abundantly attacked by polyphagous mealybugs. This study documented how different density of mealybug Pseudococcus longispinus (Targioni Tozzetti) infestation is associated with a response of antioxidative systems of Phalaenopsis × hybridum 'Innocence'. The degree of cell damage, estimated by electrolyte leakage measurement and the level of thiobarbituric acid reactive substances (TBARS), the content of pigments as well as the activity of antioxidative enzymes and proline level, as measurements of stress and stress compensation in moth orchid were examined. The highest electrolyte leakage (E L) value among samples from colonized plants was found in the orchids from series III (50 individuals/plant), whereas the lowest in the plants from series II (20 individuals/plant). The TBARS content reached the highest level at the lowest number of feeding insects (series I). Peroxidase activity toward guaiacol was significantly increased in series I (5 individuals/plant). The highest catalase activity was recorded in plants colonized by the highest number of scale insects (series III). Whereas, the highest value of proline was in series II. The content of individual photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) in plant tissues did not vary significantly between control and colonized orchids. The results have not confirmed hypothesis that the increasing number of mealybugs occurring on plant enhanced plant physiological response. The degree of longtailed mealybug infestation on plants was positively correlated only with electrolyte leakage and catalase activity in leaf tissues.

Defense Responses in the Interactions between Medicinal Plants from Lamiaceae Family and the Two-Spotted Spider Mite Tetranychus urticae Koch (Acari: Tetranychidae)

“…This suggests that antioxidant defense systems in all herbal plants were activated in longer periods of infestation. Our finding is consistent with reports that feeding of phloem-sucking insects increases lipid peroxidation [31,34,90]. Responses to oxidative stress were manifested in the maximum expression of antioxidant enzymes.…”

“…ROS may initiate destructive oxidative processes, such as chlorophyll bleaching, lipid peroxidation, protein oxidation, and nucleic acid damage, eventually leading to cell death [16,28,29]. However, plants have antioxidant mechanisms to scavenge excess ROS and prevent cell damages [30][31][32][33][34]. Low molecular weight antioxidants (ascorbic acid, glutathione and tocopherols) and ROS-scavenging enzymes have the capacity to scavenge superoxides, hydroxyl radicals and singlet oxygen [35,36].…”

Biochemical responses induced in galls of three Cynipidae species in oak trees

“…On the one hand, they are involved in the efficient removal of ROS (Gulsen et al , 2010), on the other, in generation of highly reactive quinones, which are toxic for insects (Shivashankar et al , 2012). The increase of POD activity due to insect feeding has been recorded in different plant species (Gailite et al , 2005; Taggar et al , 2012; Golan et al , 2013; Kot et al , 2015) and can be used with POD as a biochemical marker of resistant cultivars (Wei et al , 2007; Gulsen et al , 2010; Soffan et al , 2014). Enhance POD activity indicates that the stress was induced and the secondary metabolites were released as a defensive mechanism (Biswas et al , 2014).…”

Response of cassava (Manihot esculenta Crantz) genotypes to natural infestation by scale insect pest Stictococcus vayssierei Richard (Hemiptera: Stictococcidae)

“…Catalase is essential for detoxification under stress. It releases H 2 O 2 generated during mitochondrial electron transport and beta-oxidation of fatty acid ( Gill and Tuteja 2010 ; Kot et al., 2015 ). Results show that catalase activity in cassava roots pith level of improved variety 8034 was increased by scale insects infestation than improved variety Excel which had high scale insects numbers.…”

“…Scale insects have mouthparts in the form of stylets that allow them to pierce and suck liquids from the tissues or vascular cells of the plant's roots. Damage caused by scale insects is not limited to specific tissues near the feeding sites but affects the entire plant ( Kot et al., 2015 ). According to Doumtsop et al.…”