Alterations induced by Colomerus vitis on the structural and physiological leaf features of two grape cultivars.

Vitis vinifera is cultivated worldwide for its high nutritional and commercial value. More than 60 grape cultivars are cultivated in Chile. Two of these, the país and the corinto cultivars, are the oldest known and widely used for the preparation of traditional homemade drinks and consumption as table grapes. These two grape cultivars are affected by Colomerus vitis, an eriophyid mite which establishes on their leaves and forms erinea, where the mite and its offspring obtain shelter and food. Although C. vitis has a cosmopolitan distribution, few studies of its impact on the structure and physiology of affected plants have been reported. Herein we aimed to evaluate the impact of C. vitis infection on the structural and physiological leaf performance of the two grape cultivars. The results showed tissue hyperplasia and cell hypertrophy in the epidermis, with an overproduction of trichomes and emergences in the abaxial epidermis in both cultivars. The anatomical changes were similar between the país and corinto cultivars, but they were proportionally greater in the país, where the area affected by the erinea were greater. No significant changes were detected in the photosynthetic pigment content; however, there was an increase in the total soluble sugars content in the erineum leaves of the país cultivar. Higher contents of anthocyanins and total phenols, as well as the presence of the pinocembrin in the corinto cultivar, which was less affected by C. vitis, could also indicate some resistance to mites' attack, which should be investigated in future studies.

Phenolic Antioxidant Protection in the Initial Growth of Cryptocarya alba: Two Different Responses against Two Invasive Fabaceae.

The allelophatic effect of the invasive Fabaceae, Ulex europaeus and Teline monspessulana, on the production of phenolic compounds in C. alba seedlings was investigated. It was expected that the oxidative stress caused by the allelochemicals released by both invaders would induce a differential response in the production of phenolic compounds in C. alba seedlings. These antioxidant mechanisms guaranteed C. alba plants' survival, even to the detriment of their initial growth. Cryptocarya alba seedlings were irrigated with T. monspessulana (TE) and U. europaeus (UE) extracts and water as a control. After eight months, morphometric variables were evaluated, and leaves were collected for histochemical analysis. The methanol extracts from treatments and control leaves were used for anthocyanin, phenol, and antioxidant activity quantifications. Both invasive species induced an inhibitory effect on the morphometric variables. Teline monspessulana induced leaf damage and increased the anthocyanin content by 4.9-fold, but did not affect the phenol content. Ulex europaeus induces root damage and a decrease in phenol content, but does not affect the anthocyanin content. Both Fabaceae extracts affected the profile and polyphenol concentration and consequently decreased the antioxidant capacity of C. alba leaves at low extract concentrations. Phenols, lignin, and ROS accumulate on C. alba leaves, but the histochemical reactions were less intense under UE. Although C. alba develops different antioxidant protection mechanisms against stress induced by UE and TE, its survival is guaranteed, even to the detriment of its initial growth.