Fluorescência da clorofila A como indicador de porta-enxertos de manga ‘Ubá’ mais tolerantes ao déficit hídrico
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Data
2020-02-13
Autores
Silva, Leonardo Faria
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Universidade Federal do Espírito Santo
Resumo
In order to select the photochemical parameters extracted from the chlorophyll a fluorescence kinetics as being the simplest, fastest and most efficient for early identification of the most vigorous rootstock in the formation of drought tolerant mango tree, the clone of Mangifera indica L cv. Uba named ‘Uba clone 2’ (UC2) was used as scion and the seminal seedlings of “Oleo”, ‘Uba’ and “Imbu” mango were used as rootstock. Initially, rootstocks and their respective scion/rootstock combinations were analyzed: UC2/Oleo, UC2/Uba and UC2/Imbu. Then, the plants were separated into three groups: C0, none drought cycle; C1, one drought cycle and C3, three drought cycles. Each cycle contained 20 days of water deficit followed by 10 days of rewatering. Subsequently, a 35 day water deficit was applied to all groups, keeping part of it in full irrigation. The selected parameters were: F2 (relative to the presence of the L band, i.e. energetic disconnectivity of the PSII subunits), F3 (relative to the presence of the K band, i.e. imbalance between the electron flow from the Oxygen Evolution Complex to the reaction center of the PSII), DI0/RC (total energy dissipated by active reaction center), PIABS (potential performance index of the PSII), PITOTAL (total photochemical performance index). The “Oleo” rootstock was the one that generated 'Uba' mango seedlings that were more vigorous and drought tolerant when exposed to the water deficit only once. However, this tolerance decreased when the plants were subjected to recurrent droughts, losing the ability to recover after the third consecutive water deficit. In the end, it was possible to conclude that the induction of drought tolerance through differential acclimatization is dependent on the rootstock used; and confirm the use of chlorophyll a fluorescence as an indicator of 'Ubá' mango rootstocks more tolerant of water deficit.
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Mangifera indica L , Fotossíntese , Aclimatação diferencial , “Memória” ao estresse , Prolina