O-J-I-P Fluorescence Rise Kinetics Reveals Differential Cold Acclimation Capability in Sugarcane Varieties Following Exposure to Frost

摘要

In some sugarcane-producing regions of South Africa frost occurs during winter in low-lying areas (frost pockets). There is a great demand for frost tolerant sugarcane varieties as production in these frost pockets could be more profitable. Two Louisiana (USA) varieties, known to yield high sugar even when immature (LCP 85-384 and HOCP 96-540), and two South African varieties (N21 and N36) were evaluated in a field trial for frost tolerance. Kinetic analysis of polyphasic O-J-I-P fluorescence transients, and calculation of JIP-test parameters, revealed that N36 and LCP 85-384 were capable of substantial cold acclimation following the first frost, while N21 and HOCP 96-540 lacked similar capability. Exposure to further frosts altered fluorescence rise kinetics in a variety-specific fashion, with clear recovery in N36 and LCP 85-384 towards baseline kinetics, but with further deterioration in N21 and HOCP 96-540. During the period between the first frost and harvest, N36 and LCP 85-384, which were capable of cold acclimation, increased cane quality values by 26% and 21% respectively, while N21 and HOCP 96-540, which lacked similar capability, only increased these values by 9% and 11% respectively. Sugarcane varieties capable of cold acclimation therefore show promise for use in frost pockets.