Comparing the Positive Impacts and Stress Induction by Polyethylene Glycol (PEG 6000) Variable Levels on Canola (Brassica napus L.) Growth, Yield, and Oil Contents.

Seed quality (i.e., emergence energy, viability, physical purity, size, weight) is a critical factor that influences the yield of crops. Poor seed quality can lead to reduced germination rates, lower plant populations, and, ultimately, lower crop yields. On the other hand, seed priming is suggested to be an effective technique for improving seeds germination and plant population. In this study, we investigated the effect of seed priming with polyethylene glycol (PEG) on the germination, growth, and yield of two varieties of canola, super canola, and sandal canola. The treatment plan includes five concentrations of PEG (i.e., 5, 10, 15, 20%), distilled water priming, and control (no priming). All of the treatments were applied in 3 replications following a completely randomized design. Our results showed that seed priming with 5%PEG (T2) significantly improved radicle length (50 and 36%), plant height (43 and 34%), chlorophyll a (44 and 43%), chlorophyll b (120 and 208%), and total chlorophyll (83 and 111%) compared to control in super canola and sandal canola, respectively. In particular, seed priming with 5%PEG resulted in the highest increase in protein contents (25 and 1.40%), oleic acid (26 and 40%), and linolenic acid (6 and 6%) compared to control in super canola and sandal canola, respectively. It is concluded that seed priming with 5%PEG is an effective treatment to improve the performance of canola crops in terms of seedling growth, yield, chlorophyll, protein, and oil content. More investigations are recommended as future perspectives using other canola varieties to declare 5% PEG as an effective treatment for canola for improvement in growth, oil, protein, and chlorophyll contents.

Prevalence of Aflatoxins in Selected Dry Fruits, Impact of Storage Conditions on Contamination Levels and Associated Health Risks on Pakistani Consumers.

Dry fruits and nuts are nutritious foods with several health-promoting properties. However, they are prone to contamination with aflatoxins at all stages of production and storage. The present study aimed to determine the natural occurrence of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), and total aflatoxins (AFT) in dates, pistachios, and walnuts collected from four districts of South Punjab (Pakistan), and to assess the associated health risks as estimated by dietary exposure and the Margin of Exposure (MoE) determinations. The contents of AFB1 and AFT in these food products were monitored during storage under three different conditions (open-air, hermetically closed jars, and refrigeration at 4 °C) to determine the most efficient conditions in preventing aflatoxin accumulation. HPLC-fluorescence analysis of 60 samples of these products for aflatoxin contamination showed that 52 (86.7%) samples were contaminated at different levels, with a maximum of 24.2 ng/g. The overall (all samples) mean concentrations of AFB1, AFB2, AFG1, AFG2, and AFT were 3.39 ± 2.96, 1.39 ± 1.68, 1.63 ± 1.48. 1.12 ± 1.23, and 7.54 ± 6.68, respectively. The Estimated Daily Intake (EDI) and MoE of aflatoxins through the consumption of the products ranged from 0.06 ng/kg bw/day to 2.0 ng/kg bw/day and from 84.84 to 2857.13, respectively, indicating that consumers are at high health risk. Significant differences were recorded between aflatoxin levels in the samples stored under different storage conditions, with storage under refrigeration (4 °C) being the most effective in controlling aflatoxin accumulation, although storage in closed jars was also efficient and offers a more flexible alternative to retailers. The findings of the study urge official authorities of Pakistan to implement appropriate regulatory and control measures and surveillance program to alleviate the potential public health risks associated with the consumption of dry fruits and nuts in the scope of their increased consumption.

Less Conserved LRRs Is Important for BRI1 Folding.

Brassinosteroid insensitive 1 (BRI1) is a multidomain plant leucine-rich repeat receptor-like kinase (LRR-RLK), belongs to the LRR X subfamily. BRI1 perceives plant hormone brassinosteroids (BRs) through its extracellular domain that constitutes of LRRs interrupted by a 70 amino acid residue island domain (ID), which activates the kinase domain (KD) in its intracellular domain to trigger BR response. Thus, the KD and the ID of BRI1 are highly conserved and greatly contribute to BR functions. In fact, most bri1 mutants are clustered in or surrounded around the ID and the KD. However, the role of the less conserved LRR domains, particularly the first few LRRs after the signal peptide, is elusive. Here, we report the identification of a loss-of-function mutant bri1-235 that carries a mutation in the less conserved fourth LRR of BRI1 extracellular domain in Arabidopsis. This mutant had a base alteration from C to T, resulting in an amino acid substitution from serine to phenylalanine at the 156th position of BRI1. Compared with the wild-type plants, bri1-235 exhibited round leaves, prolonged life span, shorter stature, and approximately normal fertility under light conditions. The bri1-235 mutant was less sensitive to exogenous brassinolide under normal conditions. Importantly, both wild-type BRI1 expression and a sbi1 mutant that activates BRI1 rescued bri1-235 and resembled the wild type. Furthermore, bri1-235 protein was localized in endoplasmic reticulum rather than plasma membrane, suggestive of a cause for reducing BR sensitive in bri1-235. Taken together, our findings provide an insight into the role of the less conserved LRRs of BRI1, shedding light on the role of LRRs in a variety of LRR-RLKs that control numerous processes of plant growth, development, and stress response.

Effects of drought stress on hybrids of Vigna radiata at germination stage.

Drought is one the critical abiotic factors that reduces the germination, growth and yield of crops. Therefore the present project was designed with the objective to screen the best drought tolerant hybrid of Vigna radiata. Genetic variations for drought tolerance among these hybrids were assessed by simple and efficient technique. Seven hybrids of V. radiata (9801, 7002, 9706, 08003, 07007, 97012 and 08007) were used for screening against three levels of drought stress (zero, control), 5% (-0.05 MPa) and 10% (-0.1 MPa) induced by Polyethyleneglycol (PEG6000). A higher proline content was observed in 07007 (6.10 µg/g fresh weight) as compared to all other hybrids. Treated seedlings of each hybrid were compared with their respective control to evaluate the differences in their growth under drought. Different parameters such as percentage of germination, germination stress tolerance index (GSI), shoot and root weights (bath fresh and dry) and lengths, root length stress index (RLSI), dry matter stress index (DMSI) and plant height stress index (PHSI) showed considerable variations. Germination percentage, shoot weights, PHSI and DMSI decreased in all hybrids along with the increase of PEG induced drought stress (5% and 10% PEG). In contrary, root weights and RLSI were increased under drought. Overall 07007 showed a better performance, and can therefore be classified as a drought tolerant hybrid.