Physiological Response of Miscanthus x giganteus to Plant Growth Regulators in Nutritionally Poor Soil

Abstract

Miscanthus x giganteus (Mxg) is a promising second-generation biofuel crop with high production of energetic biomass. Our aim was to determine the level of plant stress of Mxg grown in poor quality soils using non-invasive physiological parameters and to test whether the stress could be reduced by application of plant growth regulators (PGRs). Plant fitness was quantified by measuring of leaf fluorescence using 24 indexes to select the most suitable fluorescence indicators for quantification of this type of abiotic stress. Simultaneously, visible stress signs were observed on stems and leaves and differences in variants were revealed also by microscopy of leaf sections. Leaf fluorescence analysis, visual observation and changes of leaf anatomy revealed significant stress in all studied subjects compared to those cultivated in good quality soil. Besides commonly used Fv/Fm (potential photosynthetic efficiency) and P.I. (performance index), which showed very low sensitivity, we suggest other fluorescence parameters (like dissipation, DIo/RC) for revealing finer differences. We can conclude that measurement of leaf fluorescence is a suitable method for revealing stress affecting Mxg in poor soils. However, none of investigated parameters proved significant positive effect of PGRs on stress reduction. Therefore, direct improvement of soil quality by fertilization should be considered for stress reduction and improving the biomass quality in this type of soils.

Photosynthetic responses of durum wheat to chemical/microbiological fertilization management under salt and drought stresses

“…F v /F m ratio in the present research was observed from 0.777 to 0.799. This parameter, expressing the maximum efficiency of PSII photochemistry in dark-adapted leaves, has been usually reported between 0.79 and 0.85 in unstressed plants (Chojak-Kozniewska et al 2018;Malinská et al 2020). Nevertheless, it is proved that F v /F m ratio is less sensitive and responsive to the stresses in comparison with the effective quantum yield of PSII (Y(II)) (Malinská et al 2020), especially to the mild stress conditions (Salvatori et al 2017).…”

“…This parameter, expressing the maximum efficiency of PSII photochemistry in dark-adapted leaves, has been usually reported between 0.79 and 0.85 in unstressed plants (Chojak-Kozniewska et al 2018;Malinská et al 2020). Nevertheless, it is proved that F v /F m ratio is less sensitive and responsive to the stresses in comparison with the effective quantum yield of PSII (Y(II)) (Malinská et al 2020), especially to the mild stress conditions (Salvatori et al 2017). In fact, the ChlF originates from de-excitation of the first excited singlet-state of Chla molecules (Roháček 2002) and has a significant correlation with Chl content (Yaghoubi Khanghahi et al 2019a).…”

Chlorophyll Fluorescence as a Criterion for the Diagnosis of Abiotic Environmental Stress of <i>Miscanthus x Giganteus</i> Hybrid

“…For most plant species, the optimal values of Fv/Fm range from 0.79 to 0.84, reduced values indicate plant stress [16]. Also, Malinská et al [25] report that measuring leaf fluorescence can be a useful tool for detecting plant stress in vivo. They assessed the Fv/Fm parameter and the performance index on M. x giganteus leaves and considered these parameters to be a suitable method for identifying significant plant stress, but they add that other indexes may detect some minor changes.…”

Efficiency of influence of foliar treatment by plant growth regulators on the parameters of miscanthus biomass

“…Аналогічні дані були отримані після обробки міскантусу двома стимуляторами росту рослин Стімпо і Регоплант (Malinská et al, 2020). Усі регулятори росту рослин містять різні сполуки та екстракти, які стимулюють розвиток рослин (Verma, Ravindran, & Kumar, 2016;Schmidt et al, 2017).…”