Gas Exchange in ‘Pome’ Banana Plants Grown Under Different Irrigation Systems

Abstract

This study aimed to evaluate Pome type bananas grown under different irrigation systems. Seventy-two treatments were used in a factorial 3x2x12 scheme, where factors consisted of three irrigation systems (under-tree sprinkling, micro-sprinkling, and dripping), two cultivars ('Prata-Anã' and 'BRS Platina'), and twelve evaluation periods (months). The treatments were arranged in a completely randomized design with five repetitions. During the third production cycle, plant phytotechnical and physiological traits were evaluated in different months at five different times of the day. The results showed no significant interactions between cultivars and irrigation systems. All the assessed traits varied for each irrigation system, except for plant yield. The banana plants presented higher vigor and a larger number of hands when grown under conventional sprinkling and microaspersion systems, regardless of the cultivar. The cultivar 'Prata-Anã' has larger leaf areas and number of hands, regardless of the irrigation system. Moreover, plants irrigated by dripping exhibited higher leaf temperatures, higher transpiration rates, and lower instant water-use efficiency. When irrigated by micro-sprinklers, the plants displayed greater water-use efficiency. As leaf temperature rose, perspiration increased linearly, while the instant water-use efficiency decreased linearly.

Growth, yield and gas exchanges of ‘D’Angola’ plantain under different plant densities

“…Carboxylase and oxygenase activities of rubisco are balanced by its kinetics, temperature, and CO 2 and O 2 substrate concentration. Under normal CO 2 concentrations, increases in temperature change the kinetic constants of the rubisco and increase the oxygenation rate preferentially to carboxylation, consequently increasing photorespiration and decreasing net photosynthesis (Taiz et al, 2017), as also found by Arantes et al (2016;2018).…”

“…RT -Readig time (hours); Q Leaf (μmol fótons m -2 s -1 ) -photosynthetically active solar radiation on the leaf; C i (μmol CO 2 mol -1 ) -internal CO 2 concentration; E (mmol H 2 O m -2 s -1 ) -transpiration rate; g s (mol H 2 O m -2 s -1 ) -stomatal conductance; A (μmol CO 2 m -2 s -1 ) -photosynthesis rate; A/C i -CO 2 carboxylation efficiency (μmol CO 2 m -2 s -1 /μmol CO 2 mol -1 ); A/E (μmol CO 2 m -2 s -1 /mmol H 2 O m -2 s -1 ) -instantaneous water use efficiency ; A/Q leaf -photosynthesis photochemical efficiency; VPD -vapor pressure deficit (kPa); Means followed by the same letter in the columns are not different by the F test at p ≤ 0.05 Table 3. Physiological variables measured at 8:00 h and 14:00 h on the third leaf of 'D' Angola' plantain subjected to different plant densities ** -Significant at p ≤ 0.01 by t test The highest photochemical efficiency was found at 8:00 h. The quantum yield of photosynthesis in C3 plants is high up to approximately 30 °C, and it decreases in banana under temperatures above 34 °C (Robinson & Galán Saúco, 2012), explaining the lower quantum efficiency at 14:00 h because of the higher leaf temperatures observed in this reading time (Arantes et al, 2016;2018).…”

Model for determining nutritional and non-nutritional limitations of Grande Naine banana in the Brazilian semiarid region

“…As the actual yield was lower than the estimated yield, it is suggested that 30.11% of the attainable yield was lost due to non-nutritional factors, e.g., weather conditions, since maximum temperatures recorded between August and December were above 34 °C while the mean air relative humidity remained below 50% (except for December) (Table 1). Under these conditions, banana plants might have undergone considerable thermal stress, thereby hindering photosynthesis rates and lowering yield Arantes et al, 2018;Ramos et al, 2018).…”

Yield of ‘Prata-Anã’ banana plants under water deficit and high plant density

“…The results might be associated with the fact that higher plant densities in semiarid regions protect the plants from strong winds and excessive radiation, improve sensible heat transfer, and reduce soil water loss through evaporation (DONATO et al, 2015). These responses contribute to the improvement of plant physiological processes including carboxylation of rubisco (ARANTES et al, 2016;RAMOS et al, 2018) and plant water use (ARANTES et al, 2018), with further increases in net photosynthesis and yield; hence, using less irrigation water is a feasible option, with gains in yield and WUE.…”