The effect of chitosan on rooting of grapevine cuttings and on subsequent plant growth under drought and temperature stress

Abstract

The effects of the treatment of grapevine cuttings with chitosan (Biochikol 020 PC) on their rooting, subsequent plant development and reaction to drought and temperature stress were investigated. 7-cm long cuttings containing a single bud were dipped in water or in Biochikol 020 PC solution at concentrations of 0.5, 1 and 2% for 24 hours at 25°C. Cutting dipped in water were served as a control. After treatment, the cuttings were rooted during 28 days at 25-28°C in the medium consisted of mixture of peat and sand (1:1, v/v). When the 1 st , 3 rd or 6 th primary root appeared the rooted cuttings were grown in optimal watering at 20°C and 32% substrate volumetric water content (VWC), which was considered optimal, under water stress (20°C, 12, 15 and 18% VWC) or temperature stress (10 and 30°C, 32% VWC). Biochikol 020 PC improved rooting of the cuttings, increased the number of new canes formed and their length, as well as the number of internodes and chlorophyll content in the leaves. The effectiveness of the compound depended on its concentration and a stage of plant development at a time when they were exposed to the drought or temperature stresses. Biochikol 020 PC was the most effective in alleviating adverse effects of drought stress when the rooted grapevine cuttings possessed six primary roots. The treatment remarkably stimulated the development of the root system, especially when the growing media moisture content was 18% (at 20°C) and when the compound was applied at concentration of 1 and 2%. Biochikol 020 PC applied at 1% also stimulated greatly the growth of the cuttings by increasing the number of internodes by 33%, the number of new canes by 29% and the length of canes by 71%, in comparison with the control. Positive effect of Biochikol 020 PC application in alleviating negative impact of temperature stress also revealed when plants were exposed to 10°C or 30°C and when the biostimulator was used at 0.5 and 1% concentration. Biochikol 020 PC increased also chlorophyll content in the leaves developed on plants kept in optimal (20°C, 32% VWC) or drought stress conditions (20°C, 12% VWC), when the biostimulator was applied at 0.5 and 1%, respectively.