Photosynthetic Efficiency of Tomato Plants Submitted to Calcium Silicate Application

Abstract

The objective was to evaluate the effect of calcium silicate on the chlorophyll content and gas exchange of two tomato hybrids. The design used was in randomized blocks in a 2x5 factorial scheme, with four replications. The first factor was composed of two tomato hybrids: Ivety and Natália, and the second factor was composed of five doses of calcium silicate (0, 150, 300, 450, and 600 kg ha-1), applied to the substrate before planting the seedlings. Gas exchange: net CO2 assimilation rate (A), leaf transpiration rate (E), stomatal conductance (gs), internal CO2 concentration (Ci), water-use efficiency (WUE), intrinsic efficiency water use (iWUE), and instant carboxylation efficiency (ACi); SPAD index and the levels of chlorophylls a, b, and total were evaluated. The analyzes were performed in the stages of first flowering (17 days after transplanting - DAT), full flowering (58 DAT), and full fruiting (78 DAT). At 17 DAT, no difference was observed for gas exchange variables and photosynthetic pigments. The application of calcium silicate reduced gas exchange and photosynthetic pigments at 58 DAT. The hybrid Natália had the highest A, WUE, iWUE, and ACi at 78 DAT. However, the hybrid Ivety in the same growth stage, in full fruiting, was superior only for the internal concentration of CO2 and SPAD index, with no difference for photosynthetic pigments.

Leaf gas exchanges and production of kale under Ca(NO3)2 concentrations in salinized nutrient solution

“…The Ci was moderately correlated with WUEi and very strongly correlated with CEi. The variables WUEi and CEi showed a strong and positive correlation among themselves (Table 2), thus demonstrating that stomatal opening is efficient for these variables, since it showed a CO 2 fixation in the leaf mesophyll without causing H 2 O loss (Coutinho et al, 2020).…”

Desempenho produtivo e bioquímico de alface crespa sob diferentes ambientes de cultivo

“…Segundo estudo de Coutinho et al (2020) [9], os pigmentos fotossintéticos, em especial os teores de clorofilas, são responsáveis pela conversão da radiação luminosa em energia, sob a forma de ATP e NADPH. Havendo assim, no decorrer do ciclo da cultura, um aumento da capacidade fotossintética das plantas, acréscimo este que se deve ao teor da ribulose-1,5bisfosfato carboxilase/oxigenase (Rubisco) [22].…”

“…Os ambientes protegidos permitem a realização de cultivos mesmo quando as condições externas são limitantes para o desenvolvimento da cultura. Sabe-se ainda que em ambientes controlados, a radiação solar do interior é reduzida em relação ao ambiente externo, ocorre redução da produção de fotoassimilados, o que altera o metabolismo vegetal, como abertura estomática e eficiência do uso da água, entre outros [9]. Para ter-se eficiente funcionamento do metabolismo vegetal é necessário que ocorra absorção de luz de qualidade que chegue aos centros das reações para conversão em produtos fotossintéticos, que influenciam na produtividade da cultura [8].…”

MORPHOMETRIC CHANGES AND POST-PLANTING GROWTH AS A RESPONSE TO HARDENING ON Tabebuia roseo-alba SEEDLINGS

“…Hence, these photosynthesizable pigments are related to the CO2 net assimilation rate. It is important to highlight that both chlorophylls have different roles on the plant metabolismchlorophyll a is a very important pigment to the plant because it appears on the photochemical phase; but chlorophyll b is an accessory pigment that, along with the carotenoids, aids the photoprotection of chlorophyll a, maximizing the energy absorption that effectively acts on photochemical reactions (COUTINHO et al, 2020). The amounts of chlorophyll a and b are found in different proportions, which occurs because the chlorophyll a and b proportion is 3:1, as a rule, but it varies according to the plant species, age of the leaf, the leaf position, and the plant crown (TAIZ; ZEIGER, 2017).…”