Shapira Or, Chernoivanov Simon, Neuberger Itamar, Levy Shay, Rubinovich Lior
Fruit Tree Sciences, Agricultural Research Organization (ARO), The Volcani Center, HaMaccabim Road 68, P.O. Box 15159, Rishon LeZion 7528809, Israel.
Fruit Tree Sciences, Agricultural Research Organization (ARO), Newe Ya'ar Research Center, P.O. Box 1021, Ramat Yishay 30095, Israel.
Plants (Basel). 2021 Jul 29;10(8):1562. doi: 10.3390/plants10081562.
The worldwide demand for avocados has resulted in the planting of millions of young plants each year. However, global warming, resulting in high temperatures, sensed as heat stress, may severely damage these new plantings. The objective of this study was to assess the risks of heat stress on young avocado plants. We aimed to characterize different physiological parameters of young 'Hass' plant leaves following exposure to high temperatures under low light (LL) intensity and to pinpoint the temperature threshold for significant heat stress damage in these plants. To this end, young potted plants were subjected to different temperature gradients in a controlled-climate chamber. Minor and severe leaf damage was apparent in plants subjected to the 51 °C and 53 °C treatments, respectively. Minor and vast reductions in optimal quantum yield efficiency of photosystem II (Fv/Fm) values were observed in plants subjected to 51 °C and 53 °C, respectively. Heat stress treatments significantly reduced CO assimilation in plants subjected to 49 °C and higher temperatures. Stomatal conductance to water vapour and substomatal internal CO concentration were less sensitive to the heat treatments. These results imply that the heat damage threshold for young avocado plants under LL conditions is between 49 °C and 51 °C, whereas at 53 °C, severe and irreversible leaf damage occurs.
全球对牛油果的需求导致每年有数百万株幼苗被种植。然而，全球变暖导致气温升高，形成热胁迫，这可能会严重损害这些新种植的植株。本研究的目的是评估热胁迫对牛油果幼苗的风险。我们旨在描述在低光照（LL）强度下暴露于高温后，‘哈斯’幼苗叶片的不同生理参数，并确定这些植株发生显著热胁迫损害的温度阈值。为此，将盆栽幼苗置于可控气候室内，使其经受不同的温度梯度。分别在经受51℃和53℃处理的植株中观察到轻微和严重的叶片损伤。在经受51℃和53℃处理的植株中，分别观察到光系统II（Fv/Fm）最佳量子产率效率的轻微和大幅降低。热胁迫处理显著降低了经受49℃及更高温度植株的CO同化。气孔导度和气孔下内部CO浓度对热处理不太敏感。这些结果表明，在LL条件下，牛油果幼苗的热损伤阈值在49℃至51℃之间，而在53℃时，会发生严重且不可逆的叶片损伤。
