FLUORESCENCE of Chlorophyll a As an Indicator of 'ubá' Mango rootstocks More tolerant to Water Deficit
Name: LEONARDO FARIA SILVA
Publication date: 13/02/2020
Advisor:
Name |
Role |
|---|---|
| DIOLINA MOURA SILVA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ALEXANDRE MARTINS COSTA SANTOS | Internal Examiner * |
| DIOLINA MOURA SILVA | Advisor * |
| JOSE AIRES VENTURA (M/D) | Internal Examiner * |
Summary: 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 'Ubá' seedlings, as scion, the Mangifera indica L cv. Uba named Uba clone 2 (UC2) was used and, as rootstock, the seminal hose seedlings Oleo, Uba and Imbu were used. 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, no dry 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, referring to the energetic disconnectivity of the PSII subunits), F3 (relative to the presence of the K band, referring to the 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 rootstock Oleo 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.
