Discipline of Horticultural Science, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, South Africa.
Discipline of Crop Science, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, South Africa.
J Sci Food Agric. 2019 Jun;99(8):4142-4149. doi: 10.1002/jsfa.9644. Epub 2019 Mar 21.
'Nules Clementine' mandarin was used to investigate the potential involvement of endogenous plant hormones in mediating citrus fruit susceptibility to rind breakdown disorder (RBD). The effect of light exposure (namely canopy position and bagging treatments) on the endogenous concentration of ABA, 7'-hydroxy-abscisic acid (7-OH-ABA), ABA-glucose ester (ABA-GE) and dihydrophaseic acid (DPA), and t-zeatin was tested using four preharvest treatments: outside, outside bagged, inside and inside bagged. Phytohormones concentration was evaluated during nine weeks of postharvest storage at 8 °C.
The shaded fruit inside the canopy had the highest RBD score (0.88) at the end of postharvest storage, while sun-exposed fruit had the lowest score (0.12). Before storage, ABA concentration was lowest (462.8 µg kg ) for inside fruit, and highest in outside bagged fruit (680.5 µg kg ). Although ABA concentration suddenly increased from the third week, reaching a maximum concentration of 580 µg kg at week 6 in fruit from inside position, it generally reduced 1.6-fold ranging from 240.52 to 480.65 µg kg throughout storage. The increase of 7-OH-ABA was more prominent in fruit from inside canopy. Overall, the concentration of ABA-GE increased three-fold with storage time. DPA concentration of bagged fruit from inside canopy position was significantly higher compared to outside fruit. The lower ABA-GE and higher DPA concentration in inside bagged fruit throughout storage also coincided with higher RBD.
The strong positive correlations between 7-OH-ABA, DPA and RBD incidence demonstrated that these ABA catabolites could be used as biomarkers for fruit susceptibility to the disorder. © 2019 Society of Chemical Industry.
“Nules Clementine”蜜橘被用来研究内源性植物激素在调节柑橘果实对裂皮病易感性中的潜在作用。通过四个预采后处理，即外果皮、外袋、内果皮和内袋，测试了光照（即冠层位置和套袋处理）对 ABA、7'-羟基脱落酸（7-OH-ABA）、ABA-葡萄糖酯（ABA-GE）和二氢相位酸（DPA）以及玉米素的内源浓度的影响。在 8°C 的条件下进行了九个星期的采后贮藏后，评估了植物激素的浓度。
在采后贮藏结束时，树冠内遮荫的果实裂皮病评分最高（0.88），而暴露于阳光的果实裂皮病评分最低（0.12）。在贮藏前，内果皮的 ABA 浓度最低（462.8μg/kg），外袋果的 ABA 浓度最高（680.5μg/kg）。虽然 ABA 浓度在第三周突然增加，在第六周达到 580μg/kg 的最大值，但在贮藏过程中总体上降低了 1.6 倍，范围从 240.52 到 480.65μg/kg。来自内冠层的果实中 7-OH-ABA 的增加更为明显。总的来说，ABA-GE 的浓度随贮藏时间增加了三倍。内冠层位置套袋果的 DPA 浓度明显高于外果皮果。在整个贮藏过程中，内袋果的 ABA-GE 浓度较低，DPA 浓度较高，也与较高的 RBD 相一致。
7-OH-ABA、DPA 和 RBD 发病率之间的强正相关表明，这些 ABA 分解产物可作为果实对该疾病易感性的生物标志物。 © 2019 化学工业协会。
