TY - JOUR
T1 - Spatiotemporal heterogeneity of photosystem II function during acclimation to zinc exposure and mineral nutrition changes in the hyperaccumulator Noccaea caerulescens
AU - Moustakas, Michael
AU - Bayçu, Gülriz
AU - Gevrek, Nurbir
AU - Moustaka, Julietta
AU - Csatári, István
AU - Rognes, Sven Erik
PY - 2019/3/8
Y1 - 2019/3/8
N2 -
We investigated changes in mineral nutrient uptake and translocation and photosystem II (PSII) functionality, in the hyperaccumulator Noccaea caerulescens after exposure to 800 μM Zn in hydroponic culture. Exposure to Zn inhibited the uptake of K, Mn, Cu, Ca, and Mg, while the uptake of Fe and Zn enhanced. Yet, Ca and Mg aboveground tissue concentrations remain unchanged while Cu increased significantly. In the present study, we provide new data on the mechanism of N. caerulescens acclimation to Zn exposure by elucidating the process of photosynthetic acclimation. A spatial heterogeneity in PSII functionality in N. caerulescens leaves exposed to Zn for 3 days was detected, while a threshold time of 4 days was needed for the activation of Zn detoxification mechanism(s) to decrease Zn toxicity and for the stomatal closure to decrease Zn supply at the severely affected leaf area. After 10-day exposure to Zn, the allocation of absorbed light energy in PSII under low light did not differ compared to control ones, while under high light, the quantum yield of non-regulated energy loss in PSII (Φ
NO
) was lower than the control, due to an efficient photoprotective mechanism. The chlorophyll fluorescence images of non-photochemical quenching (NPQ) and photochemical quenching (q
p
) clearly showed spatial and temporal heterogeneity in N. caerulescens exposure to Zn and provided further information on the particular leaf area that was most sensitive to heavy metal stress. We propose the use of chlorophyll fluorescence imaging, and in particular the redox state of the plastoquinone (PQ) pool that was found to display the highest spatiotemporal heterogeneity, as a sensitive bio-indicator to measure the environmental pressure by heavy metals on plants.
AB -
We investigated changes in mineral nutrient uptake and translocation and photosystem II (PSII) functionality, in the hyperaccumulator Noccaea caerulescens after exposure to 800 μM Zn in hydroponic culture. Exposure to Zn inhibited the uptake of K, Mn, Cu, Ca, and Mg, while the uptake of Fe and Zn enhanced. Yet, Ca and Mg aboveground tissue concentrations remain unchanged while Cu increased significantly. In the present study, we provide new data on the mechanism of N. caerulescens acclimation to Zn exposure by elucidating the process of photosynthetic acclimation. A spatial heterogeneity in PSII functionality in N. caerulescens leaves exposed to Zn for 3 days was detected, while a threshold time of 4 days was needed for the activation of Zn detoxification mechanism(s) to decrease Zn toxicity and for the stomatal closure to decrease Zn supply at the severely affected leaf area. After 10-day exposure to Zn, the allocation of absorbed light energy in PSII under low light did not differ compared to control ones, while under high light, the quantum yield of non-regulated energy loss in PSII (Φ
NO
) was lower than the control, due to an efficient photoprotective mechanism. The chlorophyll fluorescence images of non-photochemical quenching (NPQ) and photochemical quenching (q
p
) clearly showed spatial and temporal heterogeneity in N. caerulescens exposure to Zn and provided further information on the particular leaf area that was most sensitive to heavy metal stress. We propose the use of chlorophyll fluorescence imaging, and in particular the redox state of the plastoquinone (PQ) pool that was found to display the highest spatiotemporal heterogeneity, as a sensitive bio-indicator to measure the environmental pressure by heavy metals on plants.
KW - Chlorophyll fluorescence imaging
KW - Detoxification mechanism
KW - Hydroponic culture
KW - Photoprotective mechanism
KW - Photosynthetic heterogeneity
KW - Phytoremediation
KW - Redox state
KW - Zn toxicity
UR - http://www.scopus.com/inward/record.url?scp=85059855519&partnerID=8YFLogxK
U2 - 10.1007/s11356-019-04126-0
DO - 10.1007/s11356-019-04126-0
M3 - Journal article
C2 - 30623337
AN - SCOPUS:85059855519
SN - 0944-1344
VL - 26
SP - 6613
EP - 6624
JO - Environmental Science and Pollution Research
JF - Environmental Science and Pollution Research
IS - 7
ER -