Photochemical reflectance index and solar-induced fluorescence for assessing cotton photosynthesis under water-deficit stress

Using hyperspectral leaf reflectance to estimate photosynthetic capacity and nitrogen content across eastern cottonwood and hybrid poplar taxa

“…Previous physiological studies also found that wavelengths selected by our LASSO models were strongly correlated with photosynthetic capacity and leaf N content. The results of our single-leaf studies corroborated that sun-induced chlorophyll fluorescence retrieval bands (687 and 758 nm) [ 117 , 146 – 149 ] could predict V cmax , J max , and TPU. This suggests that sun-induced fluorescence techniques can be successful in estimating V cmax and J max of Populus plantations at the ecosystem level.…”

“…Due to its capacity to detect chlorophyll fluorescence signal, the wavelength 757 nm has been widely used for modeling terrestrial gross primary productivity from space [ 140 – 145 ]. In addition, 687 nm is also used for sun-induced fluorescence retrieval for estimating leaf- and canopy-level net photosynthesis of vegetation [ 117 , 146 – 149 ]. The absorption maximum positions of the excitation spectra of fluorescence also occurred at 746 nm in pea plants [ 150 ].…”

Use of thermal imaging and the photochemical reflectance index (PRI) to detect wheat response to elevated CO2 and drought

“…Previous studies show that leaves with higher water content also have higher PRI. In fact, a linear relationship was found between the two (Zhang et al, 2018). Further, if we consider that the total available energy ( E ) was the same for all plants since temperature, RH and radiation were all the same in both rooms (i.e., $$E\hspace{0.17em}=\hspace{0.17em}{E}^{{\mathrm{eCO}}_{2}}\hspace{0.17em}=\hspace{0.17em}{E}^{{\mathrm{aCO}}_{2}}$$), then for a specific evaporative cooling— LE , we can rewrite Equation () for two leaves, one grown under elevated and another grown under ambient [CO 2 ], as follows: $$${\rm{\Delta }}{{T}_{\mathrm{leaf}-\mathrm{air}}}^{{\rm{e}}{CO}_{2}}={{r}_{{\rm{a}}}}^{{\mathrm{eCO}}_{2}}(E-LE),$$$ $$${\rm{\Delta }}{{T}_{\mathrm{leaf}-\mathrm{air}}}^{{\mathrm{aCO}}_{2}}={{r}_{{\rm{a}}}}^{{\mathrm{aCO}}_{2}}(E-LE).$$$…”

“…Previous studies show that leaves with higher water content also have higher PRI. In fact, a linear relationship was found between the two (Zhang et al, 2018 ). Further, if we consider that the total available energy ( E ) was the same for all plants since temperature, RH and radiation were all the same in both rooms (i.e., ), then for a specific evaporative cooling— LE , we can rewrite Equation ( 5 ) for two leaves, one grown under elevated and another grown under ambient [CO 2 ], as follows: …”

“…Previous studies show that leaves with higher water content also have higher PRI. In fact, a linear relationship was found between the two (Zhang et al, 2018). Further, if we consider that the total available energy (E) was the same for all plants since temperature, RH and radiation were all the same in both rooms (i.e., which may interact with the crop in complex ways (Muller et al, 2021a;Still et al, 2019Still et al, , 2021.…”