Lee Seongho, Jeong Jae Hoon, Kim Seung Heui, Shin Hyunsuk
Department of Horticultural Science, Gyeongsang National University, Jinju 52725, Korea.
Fruit Research Division, National Institute of Horticultural & Herbal Science, Wanju 55365, Korea.
Plants (Basel). 2021 Oct 26;10(11):2301. doi: 10.3390/plants10112301.
Due to recent abnormal weather caused by global warming, peach flowering has gradually accelerated, and spring frost damage caused by premature de-acclimation has increased. In this study, under a simulated spring frost environment using a Soil-Fruit-Daylit-System (SFDS) chamber, we investigated whether treatment with 2% cellulose nanocrystals (CNCs) could enhance the freezing tolerance of the flower buds from 2-year-old whole peach trees. Visual changes in the ice propagation were observed using an infrared camera at the same time. After the peach flower buds in the calyx red stage were placed in the SFDS chamber with a minimum temperature of -4 °C for ~20 h, the percentage of browning in the pistils and stamens was 57.0% in the control group and 14.1% in the group treated with 2% CNCs. During the first pink stage, the percentages of browning in the pistils and stamens in the control group and the group treated with 2% CNCs were 98.2% and 70.3%, respectively. However, when peach flower buds in the group treated with 2% CNCs were exposed to a -6 °C-targeted chamber, they could not mitigate frost injury. Almost all flower buds were damaged. Infrared thermal images showed that the first exotherm in the control group began at 2:33:03 am, whereas that of the group treated with 2% CNCs began at 3:01:33 am. The control started to express exothermic behavior at -4.2 °C, while the group treated with 2% CNCs started expressing exothermic behavior at -5.1 °C. Thus, treatment with 2% CNCs enhanced the freezing tolerance by -0.9 °C and delayed the first instance of exothermic behavior by ~28 min. These results indicate that treatment with 2% CNCs could mitigate the frost damage of peach flower buds in a frost environment of -5 °C.
由于全球变暖导致近期天气异常，桃树开花逐渐加速，过早脱适应引起的春季霜冻危害增加。在本研究中，我们使用土壤-果实-日光系统（SFDS）室模拟春季霜冻环境，研究用2%纤维素纳米晶体（CNCs）处理是否能提高2年生整株桃树花芽的抗冻性。同时用红外热像仪观察冰传播的视觉变化。将处于萼片红色期的桃花芽置于最低温度为-4℃的SFDS室中约20小时后，对照组雌蕊和雄蕊的褐变率为57.0%，2%CNCs处理组为14.1%。在初花期，对照组和2%CNCs处理组雌蕊和雄蕊的褐变率分别为98.2%和70.3%。然而，当2%CNCs处理组的桃花芽置于-6℃的目标室中时，它们无法减轻冻害。几乎所有的花芽都受到了损害。红外热图像显示，对照组的第一次放热始于凌晨2:33:03，而2%CNCs处理组的第一次放热始于凌晨3:01:33。对照组在-4.2℃开始表现出放热行为，而2%CNCs处理组在-5.1℃开始表现出放热行为。因此，2%CNCs处理使抗冻性提高了-0.9℃，并将第一次放热行为延迟了约28分钟。这些结果表明，2%CNCs处理可以减轻-5℃霜冻环境下桃花芽的冻害。
