Potential Role of Biochar and Silicon in Improving Physio-Biochemical and Yield Characteristics of Borage Plants under Different Irrigation Regimes

Abstract

Silicon (Si) and biochar (Bc) are key signaling conditioners that improve plant metabolic processes and promote drought tolerance. However, the specific role of their integrative application under water restrictions on economical plants is not yet well understood. Two field experiments throughout 2018/2019 and 2019/2020 were conducted to examine the physio-biochemical modifications and yield attributes of borage plants mediated by Bc (9.52 tons ha−1) and/or Si (300 mg L−1) under different irrigation regimes (100, 75, and 50% of crop evapotranspiration). Catalase (CAT) and peroxidase (POD) activity; relative water content, water, and osmotic potential; leaf area per plant and yield attributes; and chlorophyll (Chl) content, Chla/chlorophyllidea (Chlida), and Chlb/Chlidb were considerably reduced within the drought condition. On the other hand, oxidative biomarkers, as well as organic and antioxidant solutes, were increased under drought, associated with membrane dysfunction, superoxide dismutase (SOD) activation, and osmotic adjustment (OA) capacity as well as a hyperaccumulation of porphyrin intermediates. Supplementation of Bc and Si lessens the detrimental impacts of drought on several plant metabolic processes associated with increasing leaf area and yield attributes. Their application under normal or drought conditions significantly elicited the accumulation of organic and antioxidant solutes as well as the activation of antioxidant enzymes, followed by lessening the formation of free radical oxygen and mitigating oxidative injuries. Moreover, their application maintained water status and OA capacity. Si and/or Bc treatment reduced protoporphyrin, magnesium-protoporphyrin, and protochlorophyllide while increasing Chla and Chlb assimilation and boosting the ratio of Chla/Chlida and Chlb/Chlidb, resulting in a rise in leaf area per plant and yield components following these modifications. These findings highlight the significance of Si and/or Bc as (a) stress-signaling molecule(s) in regulating defensive systems in drought-affected borage plants by boosting antioxidant aptitude, regulating water status, and accelerating chlorophyll assimilation, thus leading to increasing leaf area and productivity.

Morpho-Biochemical Modification of Petunia to Saline Water and Salicylic Acid Applications

“…Conversely, earlier investigations displayed a reduction in chlorophyll levels resulting from the decline in the assimilation of 5-aminolinolic acid, an essential intermediate of protochlorophyllide, which transforms into chlorophyll in light conditions [65]. Furthermore, salt stress persuades a decline in chlorophyll assimilation of intermediation and reductions in the expression of ChlD, Chl H, and Chl I-1 gene encoding subunits of Mg-chelatase [66,67]. Current results revealed that the spraying of SA boosted chlorophyll accumulation in salt-affected plants.…”

Effect of Dopamine on Growth, Some Biochemical Attributes, and the Yield of Crisphead Lettuce under Nitrogen Deficiency

“…Crops possess a unique defense mechanism to eradicate ROS and preserve redox homeostasis in stressful situations [11]. The antioxidant system includes enzymatic and non-enzymatic antioxidants [9,10].…”

“…More importantly, ND accelerates the over-production of reactive oxygen species (ROS) that causes ubiquitous cellular destruction and dysfunction of numerous physio-molecular responses [7,8]. Within oxidative stress, crops possess a distinct protection approach for eradicating ROS and maintaining redox homeostasis [9][10][11]. As a result, boosting ND tolerance is an effective strategy for lowering nitrogen leakage and environmental pollution caused by excessive N fertilization.…”

Role of Humic Acid on Inducing Salt Tolerance of Ivy Geranium (Pelargonium peltatum L.) Plants

“…The degeneration in chlorophyll, once salinity occurs, could result from the drop in chlorophyll biosynthetic or boosted enzymatic chlorophyll deprivation [61], in addition, the degeneration of the thylakoid membranes and devastation of chlorophyll by diverse ROS, and alterations in chlorophyll protein complexes [62]. Moreover, salinity may induce a deterioration in chlorophyll biosynthesis intermediation and decrease the expression of ChlD, Chl Hand Chl I-1 gene encoding subunits of Mg-chelatase [63,64]. As indicated in the current findings and earlier research, utilization of HA has been recorded to improve chlorophyll accumulation in plants within stress or non-stress circumstances [65,66].…”