Banca de DEFESA: STEFFANY DAIANA DA COSTA BERTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : STEFFANY DAIANA DA COSTA BERTO
DATE: 24/02/2025
TIME: 08:30
LOCAL: Defesa híbrida presencial/remota
TITLE:

Residual effect of silicate fertilizer on the morphophysiology and biochemistry of ratoon sugarcane under water stress

KEY WORDS:

Photosynthetic efficiency. Abiotic stress. Plant nutrition. Water relations. Saccharum officinarum L.. Amorphous silica.

PAGES: 134
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Física do Solo
SUMMARY:

The use of silicon (Si) has stood out as an effective tool for reducing the impacts of water stress on plants. However, there is still a need to investigate the sources, residual effects and ideal doses for sugarcane cultivation. In this sense, this research aimed to evaluate the physiological, nutritional and growth responses of the crop to the residual effect of fertilizer derived from amorphous silica (FSA) in mitigating the damage caused by water stress in ratoon sugarcane. The experiment was conducted in randomized blocks with a 4 x 2 factorial scheme, with four replications, during a period of 150 days after cutting (DAC) corresponding to four residual rates of fertilizer derived from amorphous silica, corresponding to 0.0; 78.0; 117.0, and 156.0 kg ha-1 of Si and two levels of soil moisture (40% and 80% of the maximum water retention capacity). Evaluations were carried out on growth parameters (height - SH and stalk diameter - SD, number of plants - NP and leaf area - LA), biomass (fresh mass - LFM and leaves dry mass - LDM; fresh mass - SFM, and stalk dry mass – SDM), biochemical (chlorophyll fluorescence, photochemical quantum efficiency - Fv/Fm, chlorophyll quantification – Chl a+b and carotenoids), physiological (water relations and gas exchange) and nutritional (Si, N, P, K and C in the plant). The water regime of 80% of MWRC with a dose of 156 kg ha-1 promoted increases in SH (+27.60%), SD (+5.87%), LA (+126.10%), LDM (+34.05%) and SDM (+78.40%), respectively, compared to 40% of MWRC. At 140 DAC the Fv/Fm ratio presented values of 0.66 and 0.71 for 40 and 80% of MWRC, respectively, at a dose of 156 kg ha-1. Chl a+b levels showed increases of 66.28% (40% of MWRC) and 55.21% (80% of MWRC) at a rate of 156 kg ha-1 compared to 0 kg ha-1. At 140 DAC, the water regime of 80% of MWRC with 156 kg ha-1 promotes increases in photosynthesis (+16.93%), transpiration (+25.35%) and internal CO2 concentration (+ 34.46%), in relation to 40% MWRC. The leaf Si contents were 2.47 and 6.64 g kg-1 for rates 0 and 156 kg ha-1, respectively. A rate of 156 kg ha-1 combined with 40% MWRC promoted an increase in contents of N (+27.14%), P (+84.60%) compared to a rate of 0 kg ha-1, respectively. It is concluded that the residual effect of Si rates promoted significant increases growth and in the production of fresh and dry mass of leaves and stalks of ratoon sugarcane under stress. The residual effect of increasing rates attenuated the effects of water stress to enable osmotic adjustment, reduction in electrolyte extravasation and leaf water potential, improvements in gas exchange, photosynthetic pigments and chlorophyll fluorescence. There were increases in nutrient content in ratoon sugarcane leaves under the residual effect of increasing rates of Si. Increases in nutrient levels in the leaves of ratoon sugarcane under the residual effect of increasing rates of Si. The order of extraction and export of macronutrients and Si by the variety RB041443 was: K > N > Si > Ca > P > Mg, in both MWRC.

COMMITTEE MEMBERS:
Presidente - EDIVAN RODRIGUES DE SOUZA
Interno - YGOR JACQUES AGRA BEZERRA DA SILVA
Externo à Instituição - AIRON JOSE DA SILVA - UFS