This study pursues the detection of bruised areas caused by mechanical impact on Golden Delicious apples using chlorophyll fluorescence imagery. When a fruit is impacted by a mechanical force and a bruise occurs, the chlorophyll nuclei inside the peel are damaged, which causes a reduction in fluorescence excitation compared to non-impacted areas. This difference allows automated detection of br...

A phytoplankton bloom occurred in Ardley Cove, King George Island in January 2016, during which maximum chlorophyll-a reached 9.87 mg/m3. Records show that blooms have previously not occurred in this area prior to 2010 and the average chlorophyll-a concentration between 1991 and 2009 was less than 2 mg/m3. Given the lack of in situ measurements and the poor performance of satellite algorithms i...

The photosystem II (PS-II) reaction center is composed of several polypeptides which contain carotenoids and chlorophyll. Three pigment-free extrinsic proteins, with masses 33, 24, 18 kDa, are involved in the oxygen evolving system [1]. One of the extrinsic proteins, a 33 kDa polypeptide, accelerates a dark step in the oxygen-evolving reaction [2] and preserves the binding of the Mn atoms to th...

To assess photosynthesis as a bioindicator of toxicity from polycyclic aromatic hydrocarbons (PAHs), the response of chlorophyll-a fluorescence to creosote exposure was compared with effects on population-level plant growth. Large, outdoor, freshwater microcosms containing Eurasian watermilfoil (Myriophyllum spicatum) received either a single application or multiple applications of liquid creos...

The pesticide PCP was shown to inhibit the Hill reaction in broken chloroplasts (I50 = 15 jam) and to quench chlorophyll fluorescence. Both effects require preillumination. In contrast to the common “phenol-type” inhibitors, neither inhibition of Hill reaction nor chlorophyll fluorescence quench were affected by pretreatment of chloroplast with trypsin instead o f preillumination. An inhibition...

Many plant tissues fluoresce due to the natural fluorophores present in cell walls or within the cell protoplast or lumen. While lignin and chlorophyll are well-known fluorophores, other components are less well characterized. Confocal fluorescence microscopy of fresh or fixed vibratome-cut sections of radiata pine needles revealed the presence of suberin, lignin, ferulate, and flavonoids assoc...

Precise measurements of the minimal fluorescence yield (F(o)) and maximal fluorescence yield (F(m)) of a dark-adapted sample are prerequisites for the quantification of other fluorescence parameters. The pulse amplitude-modulated chlorophyll fluorometer (PAM 101 Chlorophyll Fluorometer, Heinz Walz, Effeltrich, Germany) and saturating pulse technique have frequently been used in measuring F(o) a...

We have studied the time-resolved fluorescence properties of the light-harvesting complexes (Lhc) of photosystem II (Lhcb) in order to obtain information on the mechanism of energy dissipation (non-photochemical quenching) which is correlated to the conversion of violaxanthin to zeaxanthin in excess light conditions. The chlorophyll fluorescence decay of Lhcb proteins LHCII, CP29, CP26, and CP2...