Impact of biostimulants based amino acids and irrigation frequency on agro-physiological characteristics and productivity of broccoli plants

Abstract scientists are concerned about the utilizing of biostimulants-based amino acids in plant feeding and mitigating negative effects of water stress. As a result, two-year field experiments were conducted at Faculty of Agriculture's experimental station at Cairo University to study the effectiveness of liquid yeast waste (CMS) and Cargo amino acids (AAs) on the agro-physiological features of broccoli plants with different irrigation frequencies (every 5, 10, and 15 days). Compared with control plants, the foliar application of AAs and CMS significantly increased plant height, photosynthesis pigments, head weight, head diameter, head height, plant yield, and quality at different irrigation frequencies. Likewise, both treatments (CMS and AAs) significantly improved ascorbic acids by 16.65% and 15.95% and increased total phenol content by 24.10% and 36.60%, respectively, compared to control plants. Accordingly, the highest productivity was achieved for broccoli grown under irrigation every five days with the CMS bio-stimulant, where it was 3111.17 kg ha-1, while the lowest productivity was achieved for the control treatment in which no biostimulants were added and irrigation frequency every 15 days, and the productivity was 1376.22 kg ha-1. Plants irrigated every 15 days produced the highest levels of abscisic acid (ABA) and superoxide dismutase (SOD), followed by plants irrigated every 10 days and every 5 days. Exogenous application of amino acids bio-stimulants could be suggested to improve vegetative growth, biochemical characteristics, productivity, and nutritional value as well as to mitigate negative effects of water scarcity.

Pre-harvest application of proline, methionine, and melatonin improves shelf-life and maintains nutritional quality of Brassica oleracea florets during cold storage

The reduction in shelf-life and nutritional value of cauliflower florets are the most vital problems during cold storage. This research was performed to explore the impact of the pre-harvest foliar implementation of proline (PR), methionine (MT), and melatonin (ML), at a rate of 25 mg.L−1, on shelf-life and active composites of cauliflower florets (cv. ‘Arasya’) stored at 10 °C for 14 d. The obtained results exhibited that florets from treated plants with PR, MT, and ML were lower in water loss, electrolyte leakage, browning index, and titratable acidity (TA) compared with untreated plants, at the end of storage. Furthermore, these pre-harvest treatments significantly slow down the loss of total sugar content, reducing sugar, total soluble solid (TSS), glucosinolates concentration (Gly), total phenols (TP), vitamin C (VC), and antioxidant activity (DPPH) than control samples. After 14 days of storage, the application of PR, MT, and ML significantly improved the activity levels of phenylalanine ammonia-lyase (PAL), and catalase (CAT) as well as declined the polyphenol oxidase (PPO), peroxidase (POD) activates in the florets during the cold storage. Therefore, the pre-harvest application of PR, MT, and ML might be promising substances to keep the nutritional quality of cauliflower forests and reduce the browning index during cold storage