Effects of Salicylic Acid and Calcium Chloride on Heat Tolerance of Poinsettia
Journal
Hortscience
Journal Volume
54
Journal Issue
3
Pages
499-+
Date Issued
2019
Author(s)
Abstract
Exogenous application of either salicylic acid (SA) or calcium chloride (CaCl 2 ) to alleviate heat stress has been extensively studied. However, the effects of combined SA and CaCl 2 treatment on the heat tolerance of poinsettia have been poorly studied. This study investigated the role of a foliar spray comprising SA and CaCl 2 in managing heat tolerance of three poinsettia ( Euphorbia pulcherrima Willd.) cultivars, Noel, Winter Rose (WR), and Ice Punch�� (IP). Plants were pretreated with SA, CaCl 2 , or combined SA and CaCl 2 and then exposed to a temperature of 42 �XC for 1 hour. Changes in the relative injury (RI) percentage, malondialdehyde (MDA) content, and antioxidant enzyme activities were determined. All plants were then placed in an environment-controlled greenhouse for 14 days and evaluated. Lateral bud sprouting (%), new leaf numbers, and phenotypic appearance were recorded. Results revealed that the three poinsettia cultivars varied in their appearance, morphological growth patterns, and ability to tolerate high-temperature stress. Plant growth of ��Noel�� was more robust than that of ��WR�� and ��IP��, which were considerably affected by heat stress, resulting in brown, withered leaves and defoliation. In general, the effects of the combined application of SA and CaCl 2 on heat-tolerant ��Noel�� were superior to those of individual applications and no treatment (for control groups) in terms of the RI percentage, lateral bud sprouting (%), and appearance under heat stress. Application of combined SA and CaCl 2 for ��Noel�� plants was more beneficial for enhancing catalase activity and resulted in the effective alleviation of decreased malondialdehyde content under heat stress. Treatment including 200 �g�O SA and 10 m m CaCl 2 may alleviate heat stress and may prove useful in breeding programs focused on improving poinsettia cultivars.
Type
journal article