Potassium fertilization as salt stress attenuator in sour passion fruit

Souza, Weslley Bruno Belo de; Lima, Geovani Soares de; Paiva, Francisco Jean da Silva; Soares, Lauriane Almeida dos Anjos; Fátima, Reynaldo Teodoro de; Silva, André Alisson Rodrigues da; Gheyi, Hans Raj; Fernandes, Pedro Dantas

doi:10.1590/0103-8478cr20210769

ABSTRACT:

Water scarcity associated with irregular rainfall in the semi-arid region of Northeastern Brazil stands out as a limiting factor for agricultural production. Thus, the use of waters with high concentration of salts is an alternative to expand irrigated agriculture in this region. In this context, this study evaluated the water status, intercellular electrolyte leakage, photosynthetic pigments, and gas exchange of ‘BRS SC1’ sour passion fruit as a function of irrigation with water of different levels of salinity and potassium doses. The experiment was carried out in pots adapted as drainage lysimeters under field conditions at the Experimental Farm of the Federal University of Campina Grande in São Domingos - PB, Brazil. The experimental design was randomized blocks, in a 5 × 4 factorial scheme, whose treatments were obtained by combining two factors: five levels of electrical conductivity of irrigation water - ECw (0.3, 1.1, 1.9, 2.7, and 3.5 dS m^-1), associated with four potassium doses (60, 80, 100, and 120% of the recommendation), with three replicates. Water with electrical conductivity greater than 0.3 dS m^-1 reduced the relative water content, chlorophyll a and chlorophyll b contents, CO₂ assimilation rate, and instantaneous water use efficiency of ‘BRS SC1’ sour passion fruit plants. The estimated potassium dose of 85% of the recommendation (equivalent to 293 g per plant per year) mitigated the deleterious effects of salt stress on stomatal conductance, transpiration, internal CO₂ concentration, and instantaneous carboxylation efficiency of passion fruit ‘BRS SC1’.

Key words:
salt stress; attenuation; semi-arid region; Passiflora edulis Sims.

[1] E-mail: geovanisoareslima@gmail.com. ^*Corresponding author

--------------------------------------------------------------------Chemical characteristics--------------------------------------------------------------------
pH_H2O	OM	P	K⁺	Na⁺	Ca²⁺	Mg²⁺	Al³⁺	H⁺
(1:2.5)	dag kg^-1	(mg kg^-1)	cmol_c kg^-1
7.82	0.81	10.60	0.30	0.81	2.44	1.81	0	0
-------------------Chemical characteristics----------------------			------------------------------Physical characteristics--------------------------------
EC_se	CEC	SAR_se	ESP	Particle-size fraction (g kg^-1)			Moisture (dag kg^-1)
(dS m^-1)	cmol_c kg^-1	(mmol L^-1)^0.5	%	Sand	Silt	Clay	33.42 kPa¹	1519.5 kPa²
1.52	5.36	6.67	15.11	820.90	170.10	9.00	12.87	5.29

Source of variation	DF	---------------------------------------------Mean squares-----------------------------------------
		RWC	IEL	Chl a	Chl b	Car
Saline levels (SL)	4	248.95^**	39.81^*	75.40^*	4.21^*	3.81^*
Linear regression	1	889.98^**	115.95^**	294.34^**	16.59^**	11.32^**
Quadratic regression	1	90.46^ns	30.82^*	0.35^ns	0.005^ns	3.10^*
Potassium doses (PD)	3	22.95^ns	30.55^*	0.90^ns	0.56^ns	1.42^ns
Linear regression	1	25.12^ns	51.95^*	0.21^ns	0.003^ns	0.48^ns
Quadratic regression	1	42.50^ns	41.02^*	0.64^ns	0.100^ns	0.21^ns
Interaction (SL × PD)	12	19.73^ns	10.48^ns	19.25^*	1.18^ns	1.07^ns
Blocks	2	27.18^ns	1.28^ns	15.32^ns	1.42^ns	1.69^ns
Residual	38	12.75	8.90	10.33	0.87	0.72
CV(%)		5.21	19.72	14.17	18.27	13.44

Source of variation	DF	---------------------------------------------Mean squares-----------------------------------------------
		gs	Ci	E	A	CEi	WUEi
Saline levels (SL)	4	0.021^*	9199.18^**	1.57^*	147.62^*	0.015^**	12.72^*
Linear regression	1	0.07^**	33533.63^**	4.88^*	484.12^**	0.055^**	5.76^*
Quadratic regression	1	0.007^ns	971.52^ns	1.17^ns	84.27^*	0.004^*	1.20^ns
Potassium doses (PD)	3	0.003^ns	184.75^ns	0.59^ns	18.64^ns	0.001^ns	2.43^ns
Linear regression	1	0.006^ns	4.81^ns	0.36^ns	47.52^ns	0.002^ns	4.04^ns
Quadratic regression	1	0.0002^ns	470.40^ns	0.20^ns	2.80^ns	0.0003^ns	0.51^ns
Interaction (SL × PD)	12	0.006^*	2579.78^*	0.87^*	31.76^ns	0.002^*	9.39^ns
Blocks	2	0.0009^ns	587.85^ns	6.08^*	40.74^ns	0.0005^ns	29.80^*
Residual	38	0.002	716.48	0.41	21.58	0.0008	2.92
CV(%)		25.18	14.90	12.51	13.69	14.76	11.85

Brasil

Brasil

Potassium fertilization as salt stress attenuator in sour passion fruit

Adubação potássica como atenuante do estresse salino em maracujazeiro-azedo

ABSTRACT: