Journal of Plant Physiology and Breeding
Volume:11 Issue: 1, Winter-Spring 2021

Salinity is a harmful environmental factor threatening plant growth and productivity through ionic and oxidative stresses. These detrimental effects of salinity could be modulated by some plant growth regulators. Salicylic acid (SA) as a phenolic molecule regulates growth and development and also induces crucial defense mechanisms in plants under salinity. This growth regulator can also improve some physiological and biochemical processes of salt-stressed plants such as reducing Na+ influx to the root cells and increasing essential nutrients uptake. Application of SA can also help plants to accumulate the toxic Na+ in vacuoles through enhancing the activities of H+-pum- stressed plants. Some reports indicate that salicylic acid counteracts salt-induced water deficit by elevating plant osmolytes including soluble sugars, proline, and glycine betaine. These essential roles as well as the effect of SA in the augmentation of chlorophyll and photosynthetic activities can potentially improve plant growth and productivity under saline conditions. The possible cross-talks of salicylic acid with other growth regulators are also important for promoting salt tolerance and the performance of plants under stressful conditions.

In recent years, with the spread of drought and increasing demand for water, the need for water management in irrigation of plants has become more apparent. Present investigation studied yield-related biochemical responses of sugar beet to vermicompost and phytoprotectants to mitigate drought stress based on a split-plot-factorial design with three replications. The main plots consisted of irrigation at 90%, 70%, 50%, and 30% field capacity (FC). The subplots subjected to treatments comprised a factorial combination of vermicompost (0 and 7 Mg/ha) and foliar application of phytoprotectants [distilled water as a control, zinc (5μM), silicon (4mM), glycine betaine (4mM) and ascorbic acid (0.5mM)]. The findings showed that concentration of ascorbate peroxidase, catalase, dehydroascorbate reductase, glutathione peroxidase, and superoxide dismutase, were significantly enhanced under stress conditions. Despite the higher sugar percentage, the lower root yield and biomass were recorded in the plants irrigated with 30 and 50% FC. Sugar content increased gradually in response to increasing in water deficit (from 70% to 30% FC). Root yield increased insignificantly with zink, glycine betaine, and ascorbic acid treatments. The highest root yield was obtained at 70% FC that followed by other water regimes (90, 50, and 30% FC, respectively). Malondialdehyde increased with increasing stress level but it decreased when phytoprotectants, especially glycine betaine, were applied. Vermicompost treatment had positive effect on the prevention of lipid peroxidation.  It can be concluded that phytoprotectants and vermicompost protect sugar beet plants from drought-induced oxidative stress, and improve root and sugar yield by enhancing plant water-stress tolerance.

Some of the harmful impacts of water shortage on crop performance may be alleviated by growth regulators such as salicylic acid. So, an experiment was arranged as a split-plot design based on randomized complete blocks in three replicates to assess changes in essential oil content of dill (Anethum graveolens L.) organs in response to water availability (water supply after 70, 100, 130, 160 mm evaporation as normal watering and mild, moderate and severe stresses, respectively), and salicylic acid (SA) levels (water spray and 0.6, 1.2 mM SA). Irrigation levels and salicylic acid treatments were assigned to the main and sub-plots, respectively. The results showed that chlorophyll a and especially chlorophyll b decreased with increasing drought stress. The ground green cover and plant organ masses (leaves and stem, flowers, and seeds) were only decreased under severe water deficit. Essential oil percentage of dill organs increased with increasing water deficit up to moderate stress, but thereafter it was decreased as water deficit severed. The highest essential oil yield of the vegetative parts and flowers was also produced in moderately stressed plants, but the greatest essential oil yield of seeds was recorded under mild water deficit. Exogenous salicylic acid enhanced the essential oil percentage of all dill organs, especially under moderate water limitation. The essential oil yield of dill organs was also increased by the salicylic acid treatment. The application of 1.2 mM salicylic acid was more effective in improving essential oil production of dill.

The present study was aimed to investigate the physiological responses of the leaves of Ulmus minor to air pollutants such as ozone, carbon monoxide, and nitrogen dioxide to verify the ability of this species to resistant the air pollutants. The leaves of Ulmus minor Mill. were collected from one location (Chaloos) in the Mazandaran province with lower air pollution and three locations in the Tehran province (Tajrish, Park Laleh, and Park Shahr) with higher air pollutions. The leaves were randomly collected from the middle part of the crowns in each sampling location with five replications and the growth and physiological characters were measured. The climate factors of the sampling locations were also evaluated. The results showed that dry matter, protein, chlorophyll a, anthocyanin, and activity of the peroxidase enzyme in the plants grown in Park Shahr with higher amount of air pollutants was almost 35, 50, 30, 50, and 40 percent higher than those of the plants grown in Chaloos with the lower amount of air pollutants, respectively. The number and intensity of peroxidase isoenzyme bands were significantly higher in the leaves of plants collected from the locations in Tehran province. However, the prominent role of rainfall on the physiological responses of Ulmus minor cannot be ignored. It seems that Ulmus minor is a resistant tree to air pollutants and it might be considered as a biological filter in removing gaseous pollutants in areas like Tehran city to improve air quality.

Mango fruit is one of the most important fruits in terms of nutritional value. One of the important characters of mango is the presence of antioxidants such as polyphenols, carotenoids, and anthocyanins in its fruits and vegetables. These compounds are involved in preventing diseases and maintaining health in humans. Amino acids have been used to preserve and enhance fruits quality. In this study, the mango fruits of a local cultivar were sprayed with the arginine amino acid at concentrations of 0, 200, and 400 µM at the time of fruit formation and 10 days after this stage. Results showed that total phenolics, anthocyanins, carotenoids, antioxidant capacity, total soluble solids, pH, fruit weight, and seed weight of the fruits increased with the increase in arginine concentration and 400 μM arginine had a better effect on these characters. Comparison of the times of application indicated that the second stage of the foliar application was generally more effective than the first stage in increasing the studied characters.

To improve the growth of olive and find a suitable approach for controlling Verticillium dahlia in this plant, treatment of different cultivars by salicylic acid (SA) was evaluated. Nine-month-old seedlings of Koroneiki, Marry, Rowghani, and Zard cultivars were pre-treated with 0, 5, and 10 mM SA at 15-days intervals, and then roots were inoculated by dipping into a defoliating isolate of V. dahliae. The dry weight of different tissues was measured separately at the end of the trial (14 weeks after inoculation). The response was assessed by grading the severity of symptoms on the 0-4 scale and calculating the area under the disease progress curve. Also, the concentration of phenolic compounds in the root tissues, the activity of the superoxide dismutase enzyme, the final intensity of symptoms, and the percentage of dead plants were measured. Foliar spray of 10 mM SA increased the vegetative growth of the olive cultivars. The results showed that treatment with SA decreases the severity of Verticillium wilt. The root phenol level and the activity of superoxide dismutase were significantly higher in the plants treated with 10 mM SA as compared to the control plants. Disease progression had a negative relationship with the superoxide dismutase activity and total phenols of the roots in olive cultivars.

In the 21st century, climate changes and global warming have become critical concerns, in that they can affect many of the natural phenomena. It is reported that aeroallergen sensitization is influenced by changes in climate. Bet v 1 is an important birch pollen respiratory allergen and a prototype for the PR-10 protein family, which has been reported in wheat pollen. Two wheat genotypes were exposed to water deficit at the meiosis stage of anthers to investigate the effect of drought stress changes on wheat pollen Bet v 1 expression. Then, mature anthers of wheat underwent molecular experiments in the anthesis stage. Expression analysis was carried out, using Real-time PCR, on the Bet v 1 gene that encodes allergens. The results indicated the induction of Bet v 1 in both genotypes in the water deficit condition. The genotype which had been improved by breeders for tolerating drought more than the other genotype revealed more increase in Bet v 1 expression. Given the great spread of wheat, especially improved genotypes worldwide as a pivotal and crop plant and regarding wheat pollen effect on provoking allergy in humans, Bet v 1 can cause new distress in human society. Therefore, this finding is considered as a new verification of concerns of climate change on human health, which emphasizes the importance of efforts to alleviate climate changes to avoid the risk of public health.

One of the largest monocotyledonous genus in the Amaryllidaceae family is the Allium genus that includes approximately 900 species. This study aimed to examine the variations and clustering of eight Iranian endemic Allium species based on karyotype features. The species were collected from wild habitats across different geographical areas of Iran. A. sativum, A. stipitatum, A. fistolosum, A. umbellicatum, A. stamineum, A. lenkoranicum, and A. rubellum, were diploids (2n = 2x = 16), but A. atroviolaceum was triploid (2n = 3x = 24). The results represent x = 8 for basic chromosome numbers in all species. Analysis of variance showed significant interspecific variations for all eight chromosomal parameters tested. The mean of chromosome lengths was 11.19 μm, varied from 8.59 μm to 13.81 μm for A. atroviolaceum and A. stipitatum, respectively. In all species, the chromosome types were determined as mostly metacentric (m) and submetacentric (sm), formed five different karyotype formulas of 16m (A. stipitatum, A. fistolosum, A. stamineum), 14m+2sm (A. sativum, A. rubellum), 12m+4sm (A. lenkoranicum), 10m+6sm (A. umbellicatum), and 24m (A. atroviolaceum). According to Stebbins' classification, all karyotypes were grouped in the 1A class and represented the most symmetrical karyotypes. The information obtained from karyotype and chromosome morphology has an appreciable value in understanding the taxon evolution and interrelations.

Sunflower (Helianthus annuus L.) is one of the most important oilseed crops in the world. Basal stem rot, caused by Sclerotinia spp., is an important disease of sunflower causing considerable yield losses worldwide. Effective improvement for disease resistance relies on the understanding of the interaction between pathogen and host. A total of 100 sunflower genotypes from different worldwide agricultural research institutions were evaluated for their responses to three isolates of each of the S. sclerotiorum and S. minor at the seedling stage in the controlled conditions. Remarkable significant host-pathogen isolate interaction indicates the existence of vertical or isolate-specific resistance in the studied sunflower germplasm against Sclerotinia spp. Genotype-by-pathogen biplot analysis was performed to observe the pathogenicity of the two fungi on host genotypes and facilitate the simultaneous visualization of the relationship among the pathogens and genotypes. The first two principal components accounted for 95.86% and 79.77% of the total variation of the genotype-isolate interaction of S. sclerotrium and S. minor, respectively. The GGE biplot related to S. Sclerotiorum isolates depicted that out of the studied genotypes, "H100A/LC1064" was resistant against the A37 isolate of S. Sclerotiorum. Among the examined germplasm, the genotype "1059" was identified as the resistant genotype against the J2 isolate of S. Sclerotiorum. None of the genotypes were resistant to the J1 isolate of S. Sclerotiorum. Regarding the generated biplot for S. minor, "8A*/LC1064C" was the most resistant sunflower genotype against the M1 isolate of S. minor. The genotype "H205A/83HR4" was located in vertex near to A1 and G2 isolates and, therefore, was resistant to these isolates of S. minor. The genetic variation detected within the sunflower collections can be utilized for the selection of diverse parents in the resistant breeding programs as well as the development of mapping populations for the QTL analysis of resistance to S. sclerotiorum and S. minor.

Effects of several soilless growing media on the flowering time, flower bud number, flower number, flower size, and stem height of Lilium cut flower was studied. The treatments were arranged as factorial based on a completely randomized design with 10 growing media and two cultivars of Bernini (Oriental) and Ceb Dazzle (Asiatic) using four replications. The growing media were different organic and mineral components as sand, vermiculite, perlite, cocopeat, and their combinations at equal volumes (50:50). Daily fertigation of the pots with 250 ml of the Hougland solution was carried out, which started one week after sowing the bulbs. Growth and development of plants were monitored and the data was recorded accordingly. The results indicated that cocopeat as a culture medium was superior to others in terms of accelerating flowering time, flower bud number per plant, flower number per plant, flower size, and stem height in both cultivars. The earliest flowering was observed on Bernini and Ceb Dazzle CVs. cultivated in sand and vermiculite media, respectively. The media containing cocopeat (50 and 100 percent) yielded the higher flower bud and flower number, flower size, and stem height in comparison to other mixtures.

Phytate, the highest inorganic phosphorus in cereal grains, is an anti-nutritional factor that reduces the bioavailability of iron (Fe) and zinc (Zn). The whole grains of 109 hexaploid landraces and modern bread wheat cultivars (Triticum aestivum L.) were used to determine Fe, Zn, and phytate concentrations and their bioavailability using phytate:mineral molar ratios. In addition, some morphological and physiological features were identified as contributory factors for the screening process. In the field experiment, the concentrations of Fe and Zn, ranged between 0.036-0.255 mg/g and 0.030-0.085 mg/g, respectively. There were no significant differences in Fe and Zn concentration between the bread wheat cultivars and landraces. Therefore, efforts made by breeders for developing high-yielding wheat didn’t have detrimental effects on Fe and Zn concentrations. The modern bread wheat cultivars showed a significantly higher phytate concentration than landraces. Grain phytate ranged from 15.07-28.77 mg/g resulting in a variation in phytate:Fe of 6.24-58.14 and phytate:Zn of 32.20-77.22, indicating poor bioavailability of these minerals. The identified drawbacks were due to relatively high phytate concentration which in turn could be due to a high level of soil phosphorus concentration, suggesting increasing mineral bioavailability by the breeding methods to reduce the phytate and phytate:mineral ratio. In the solution culture experiment, the role of root length, root dry weight, and root nutrient concentration in distinguishing cultivars’ Fe uptake was demonstrated. The study also revealed that lower values of root length, root dry weight, and leaf dry weight led to lesser leaf Fe which in turn caused reduced contents of photosynthetic pigments and chlorophyll fluorescence. Due to high Zn and Fe concentration, and low concentration of phytate and phytate:mineral molar ratio, some of the current landraces such as Khoram Abad (1), Sarouq (4), Eskan Arak (2), and Hoseinabad Arak could be exploited by breeding strategies in biofortification programs.

Improving knowledge on the relationships between agro-morphological traits in Chitti bean (Phaseolus vulgaris L.) will contribute to identifying key traits affecting grain yield for use in bean breeding programs. A field experiment was conducted using an augmented design consisting of 116 breeding lines and three checks (Sadri, Kousha, Khomein local). Statistical analysis showed that grain yield and seeds per plant had the largest variations. Regression analysis showed that days to emergence of the first trifoliate leaf (V3), seeds per pod, and plant height, explained more than 39 percent of the variation in grain yield. Path analysis indicated a high negative direct effect of V3 and a positive direct effect of seeds per pod on grain yield. Cluster analysis helped to classify all genotypes into four distinct groups. From the genotypes studied, 38 superior genotypes were selected, which can be used in the breeding programs of Chitti bean Also, number of days to emergence of the first trifoliate leaf and the number of seeds per pod were identified as traits useful to consider in bean breeding programs aiming at improving the grain yield of Chitti beans.