Effects of low-temperature acclimation on morphological and physiological indices of banana seedlings

Abstract

Aim: Climate change has become the most important factor limiting the banana cultivation area, especially in countries with subtropical climates. To assess the effect of cold stress on banana, twenty-eight global and local cultivated clones were used for morphological and physio-biochemical evaluation. Methods: The banana clones were produced from shoot tips under in vitro conditions. When the plants were 20-25 cm in height and 5-6 leaves, they were transferred to climate-controlled rooms. The temperature of the testing room was gradually decreased every three days (from 28ºC day/22ºC night to 4ºC day/-1ºC night). After the seedlings remained at these temperatures, the temperature of the room was increased every three days (from 4ºC day/-1ºC night to 28ºC day/22ºC). When the treatment room reached control room conditions (28ºC day/22ºC night), measurements and analyses were started. Results: Low-temperature stress decreased pseudostem length, pseudostem diameter, leaf area, and leaf number of banana clones. The malondialdehyde contents (MDA) were increased compared with control; the chlorophyll content and fluorescence decreased significantly. When temperatures return to normal conditions (28ºC day/22ºC night), only eight banana clones managed to survive and twenty banana clones irreversibly died. After a gradual increase in temperatures, plants have continued to live and form new leaves. Conclusion: At the end of study, it was understood that the low temperatures applied would be sufficient to determine the low-temperature tolerance in banana clones and could work at lower temperatures