Diplotaxis tenuifolia (L.) DC. Yield and Quality as Influenced by Cropping Season, Protein Hydrolysates, and Trichoderma Applications

Abstract

Increasing attention is being given to plant biostimulants as a sustainable farming practice aimed to enhance vegetable crop performance. This research was conducted on greenhouse-grown perennial wall rocket (Diplotaxis tenuifolia (L.) DC.), comparing three biostimulant treatments (legume-derived protein hydrolysates, Trichoderma harzianum T22, and protein hydrolysates + Trichoderma harzianum T22) plus an untreated control, in a factorial combination with three cropping seasons (autumn–winter, winter, winter–spring). Measurements were performed on leaf yield components, colorimetric indicators, mineral composition, bioactive compounds, and antioxidant activity. Leaf marketable yield and mean weight, as well as plant dry weight, showed the highest values in winter crop cycle. Biostimulant treatments resulted in 18.4% and 26.4% increase in leaf yield and number of leaves per rosette, respectively, compared to the untreated control. Protein hydrolysates led to the highest plant dry weight (+34.7% compared to the control). Soil plant analysis development (SPAD) index as well as NO3, PO4, SO4, and Ca contents were influenced more during the winter–spring season than the winter cropping season. The winter production season resulted in a 19.8% increase in the leaf lipophilic antioxidant activity, whereas the hydrophilic antioxidant activity was 34.9% higher during the winter–spring season. SPAD index was the highest with protein hydrolysates + Trichoderma applications, which also increased the colorimetric parameters compared to the untreated control. The treatment with protein hydrolysates + Trichoderma enhanced N, PO4, Mg, and Na contents, compared to both biostimulants applied singly and to the untreated control. Both biostimulants applied alone or the protein hydrolysates + Trichoderma combination led to the increase of the lipophilic and hydrophilic antioxidant activity, as well as ascorbic acid and chlorophyll b, compared to the untreated control. The present research revealed that protein hydrolysates and Trichoderma single applications, and even more their combination in the case of some nutrients content, represent an effective tool for enhancing the yield and the quality attributes of perennial wall rocket produced under the perspective of sustainable crop system.

Application of Trichoderma harzianum, 6-Pentyl-α-pyrone and Plant Biopolymer Formulations Modulate Plant Metabolism and Fruit Quality of Plum Tomatoes

“…It is well documented that lycopene is the main lipophilic antioxidant found in tomato fruits, and its increase is particularly important because it could assure a longer shelf-life of plum tomatoes. On the contrary, polyphenols that behave as free radical scavengers and take part in redox reactions due to their ability to transport protons and electrons and confer resistance to abiotic stresses and pathogens [ 54 , 55 ], were not affected by Trichoderma , metabolites or BP applications, as recently found by Caruso et al [ 56 ]. This result could mean that there is a basal constitutive amount of polyphenols in plum tomatoes that is independent of influences by external stimuli.…”

Recent Advances in the Molecular Effects of Biostimulants in Plants: An Overview

“…Commercial PHs (Sinergon Bio) of animal origin applied to olive tree (Olea europaea) were associated with positive effects on plant growth and increased photosynthetic rate [82]. Similarly, PHs application in Diplotaxis tenuifolia L. also led to an increase in plant dry weight, improved efficiency in chlorophyll biosynthesis and increased activity of the photosynthetic system [83]. The authors also reported an increase in nutrients such as sodium, nitrate, magnesium, potassium, calcium and phosphate, when applied in combination with the microorganism Trichoderma Harzianum T22.…”

Functional Hyperspectral Imaging by High-Related Vegetation Indices to Track the Wide-Spectrum Trichoderma Biocontrol Activity Against Soil-Borne Diseases of Baby-Leaf Vegetables

“…include a plethora of isolates with biocontrol activity against phytopathogens (Kumar et al, 2017 ) that can also give additional benefits to the plants, such as increase the nutrient uptake, enhance the photosynthetic activity and stimulate different metabolic processes that positively affect yields and quality of the treated crops (El Enshasy et al, 2020 ). Recently, it has been shown that soil treatment with Trichoderma gave biostimulant effects on wild rocket and baby lettuce, ranging from the increase of leaf yield, fresh and dry weight, to the improvement of leaf nutritional status, resulting in a premium quality of the fresh-cuttings with higher lipophilic antioxidant activity and total ascorbic acid content (Fiorentino et al, 2018 ; Caruso et al, 2020 ; Di Mola et al, 2020 ; Rouphael et al, 2020 ). However, expressing the full biocontrol potential in these contexts, Trichoderma -based formulates can successfully integrate disease management protocols for producing baby leaf vegetables with high added value in terms of sustainability, decreasing the dependence on synthetic fungicides.…”