Iranian Journal of Plant Physiology
Volume:13 Issue: 4, Summer 2023

The response of rice towards phosphorus (P) deficiency, from vegetative growth to crop maturity, grain yield, and grain quality, has been less studied. Importance of acid phosphatases (ACP) under P-deficiency is not well understood. In this study, P-non-application (P0) was compared to P application (P30) at a rate of 30 kg ha-1 in seven rice genotypes grown under field conditions. Biomass, P-uptake, and ACP activity of shoots and roots were measured at 30 and 60 days after transplantation (DAT), while grain yield, grain size and grain-P content were measured at harvest, and grain quality after six months of storage following harvest. At 30 DAT, the biomass of shoots was most affected in Pusa44, but by 60 DAT, biomass of shoots and roots improved in CSR10/IET28816 compared to other genotypes under P0. P-uptake was most affected in Pusa44, while it improved by 60 DAT in CSR10/IET28816 compared to the other genotypes under P0. P-uptake was positively related to root growth, and ACP activity in roots under P0. At harvest, grain yield reduced in Pusa44/IET28075, and grain length reduced in Pusa44. In addition, the total P content of grains reduced in IET28066/IET28061/IET27641 under P0. In stored grains, total antioxidant capacity decreased, and oxidative stress increased to a high extent in Pusa44, while it increased to a low extent in CSR10/IET28816 compared to other genotypes under P0. The results concluded that P-uptake determined plant growth, grain yield and grain quality under P0. CSR10/IET28816 showed greater adaptation to P0 compared to the other genotypes.

The purpose of this study was to determine the interaction of plasma radiation on the growth rate and the number of leaves in several species of mangrove. The species of mangrove, which included Rhizophora stylosa, Rhizophora mucronata, Creriops tagal, and Bruguera sp. The method used was a factorial complete randomized design with 12 treatments and 3 replications. The first factor was the duration of plasma radiation, with values of 0 minutes, 30 minutes and 60 minutes. The second factor was the species of mangrove, which included Rhizopora stylosa, Rhizopora mucronata, Creriops tagal, and Bruguera sp. The parameters observed were growth rate and the number of leaves. The results showed that plasma radiation was able to increase the growth rate in R. mucronata species but did not affect the number of leaves. Plasma radiation for 60 minutes met the nitrogen requirements of the plants. This study concluded that corona incandescent plasma radiation can increase the mangrove growth rate, especially in R. mucronata species.

Mycorrhiza fungi play a key role in plants' resistance to environmental stresses. Among environmental stressors, salinity is an acute problem. One way to understand the ability of plants to deal with abiotic stress is to investigate and identify the changes that occur as a result of stress in the levels of certain proteins. The purpose of the present study was to investigate the emergence of special protein bands and their strength in barley plants under increasing salinity concentration and affected by salinity pretreated mycorrhizal fungi.The first factor of the study was pretreatment of mycorrhiza with 0, 25, 50, and 100 mmol of salt, and the second factor included 0, 25, 50, 100, and 200 mmol salinity treatments applied to the plants under study. Barly plants were analyzed by SDS-page gel electrophoresis method and staining to check changes in protein pattern. Results showed that the pattern of protein contents of the plants under stress was significantly different from that of control plants. Considering the enhanced bands or the appearance of new bands on the SDS-page gel, synthesis of some proteins increased in the plants under stress or some new proteins were produced to resist stress conditions compared to control plants. Based on the molecular weight of the proteins that have been determined in different plants and the range of bands obtained on the electrophoresis gel, the proteins of the investigated plant might be identified.

A factorial experiment was conducted based on a completely randomized design with four replications. Treatments included four salinity levels (0, 50, 100 and 150 mM) and four chitosan levels (0, 0.25, 0.50 and 0.75% by weight-volume all of which were dissolved in 1% acetic acid). After RNA extraction and cDNA synthesis, the expression of gibberellin synthesis genes (GA3OX1, GA3OX2, GA3OX3, GA3OX4, GA3OX5 and GA3OX6) was assessed using qRT-PCR, and also some biochemical indicators were measured. The results showed that salinity stress increased the activity of peroxidase and malondialdehyde (MDA) content. Seed pretreatment with chitosan at a concentration of 0.75% increased peroxidase activity and decreased MDA content. Phosphate content in seed pretreatment with 0.75% chitosan and 0 mM salinity levels increased by 57% compared to the control. With increasing salinity, the activity of superoxide dismutase, ascorbate peroxidase and glutathione reductase increased, while catalase activity decreased. The activity of superoxide dismutase in pretreatment with 0.25% chitosan, ascorbate peroxidase and glutathione reductase in pretreatment with 0.75% Chitosan increased at 150 mM salinity stress by 14%, 46% and 34%, respectively. Also, the activity of catalase enzyme in pretreatment with 0.75% chitosan and the level of 0 mM salinity stress increased by 39% compared to the control. GA3OX1 gene expression in priming treatment with 0.75% chitosan at 0 mM salinity level was higher than GA3OX2, GA3OX3, GA3OX4, GA3OX5 and GA3OX6.

Plant physiology, specifically nitrogen (N) metabolism affecting plant phenology (vernalization), may be affected under stress. We have just recently indicated it is possible to enhance wheat (Tritium aestivum L.) yield and seed quality by shortening vernalization under drought conditions using plant growth regulators (PGR). Accordingly, PGR, planting dates and cold stratification affecting plant vernalization under drought stress were investigated. The tested PGR, used for priming seeds or spraying plants (at the double bridge stage, V4-V6 stage), consisted of the single and the combined use of gibberellins (GA3, GA4, and GA7) benzyl adenine 6 (BA6), and kinetin at 100, 200, and 50, mg/l, respectively. Plant morphological properties and seed components were determined in a split plot experiment on the basis of a completely randomized block design with four replicates. Priming and spraying and their interaction significantly affected the measured parameters. Autumn planting and spraying with GA4+7 + BA6 resulted in the highest root length (15.75cm). Interestingly, seed components were more affected by the treatments in spring planting as the highest spike dry weight was resulted by spraying with GA3+4+7 + kinetin + BA6 (3.97g). Spraying at spring planting was also more affective on grain N percentage, as spring planting without priming, using GA3+7 and kinetin, and cold stratification resulted in the highest GNP (3%). The obtained results are another confirmation to our recent experiment indicating it is possible to regulate wheat phonology (vernalization) and improve its growth and seed quality using the tested PGR under drought conditions.

A decrease in air temperature harms many ornamental plants, especially flowers grown in green space. To prevent cold stress, various elicitors are used that reduce the harmful effects of low temperature. Therefore, in this study, we investigated the impact of two elicitor's salicylic acid and boric acid on the growth and yield parameters of French marigold (Tagetes patula). Next, these plants were exposed to cold stress, and their physiological and morphological traits were also studied. Results showed that the application of elicitors, especially in higher concentrations, had a positive effect on morphological and physiological traits. Interaction of SA×BA with a concentration of 2mM, increased flower diameter (20%), stem height (19%), stem and root fresh weight (27 and 35% respectively), stem and root dry weight (31 and 39% respectively), and flower quality (26%). Also, the interaction of these two elicitors led to a decrease in ion leakage (22%), malondialdehyde (28%), and proline (24%) content, and an increase in chlorophyll fluorescence (28%), catalase (20%) and ascorbate peroxidase (33%) activity. In general, the application of salicylic acid and boric acid interaction treatment with 2mM concentration improved growth and yield characteristics and cold stress tolerance in French marigold.

An experiment was conducted based on a split plot arrangement in a randomized complete block design with three replicates during 2019-2020. Experimental factors included drought stress at three levels (50, 80, and 110 mm evaporation from evaporation pan Class A), cultivar at two levels (Titicaca and Q29), and organic acids at four levels (control, humic acid, amino acid, and a combination of humic and amino acids). Findings suggested that extreme drought stress resulted in the decreasing of 20.33% plant height, 30.19% of leaf area index while increasing of 78.69% malondialdehyde content as well as 38.12% of catalase and 31.26% of peroxidase enzymes activities. Titicaca cultivar had higher plant height, leaf area index and catalase contents in amounts of 3.32%, 9.98% and 13.38% as compared with Q29. Applying organic compounds improved growth and biochemical properties of quinoa plants with the maximum positive effect in plants treated with a combination of humic and amino acids. As well as the using of these compounds decreased the negative effects of drought stress. Application of humic and amino acids seems to improve vegetative parameters of quinoa plants under both normal and drought stress conditions though increasing antioxidant enzyme activities and regulation of abscisic acid hormone.

Paclobutrazol (PBZ) retards plant growth through reducing gibberellin biosynthesis. Flowering is critical for Narcissus tazetta as a unique cut flower with commercial value. Hence, every new advancement into the cultivation of N. tazetta is crucial to meet improving its quality and yield. The pre-treatment of Narcissus bulbs with different PBZ levels (25, 50 and 100 mM) induced a significant increase in the flowering percent, flower size, scape diameter, phloem and xylem vessels, pith cavity size, leaf thickness, spongy and palisade mesophylls, and vascular bundle width, despite a significant decrease in height and fresh mass of scape at 100 mM. Mean germination time of bulbs and flowers significantly increased at 50 and 100 mM PBZ, while germination index of bulbs showed a significant increase at 25 mM. Under PBZ treatment, the observed increase in the photosynthetic pigments was followed by high accumulation of sugars. Moreover, different concentrations of PBZ significantly increased anthocyanin, phenols, proteins, proline, and total antioxidant activity in the Narcissus leaves and flowers. No changes in H2O2, malondialdehyde, and activity of catalase and ascorbate peroxidase can be related to no stress-inductive effects of PBZ treatment in Narcissus. Overall, the positive effect of PBZ on physiological, morphological and anatomical function in flowering procedure in N. tazetta offer suggestions of its future usage in other ornamental bulbous plants.

 Soil salinity has become a very serious issue in many parts of the world. Salinity is the most important factor limiting plants growth in these areas. Therefore, in order to make better use of saline soils, it is necessary to identify salinity-resistant plants. The aim of this study was to evaluate the effect of salinity on the response of two Prosopis species to salt stress at arid and semi-arid lands. The present study was done as a factorial experiment based on a completely randomized design. The first factor was salinity of 1.8 (control), 5.8, 10.2 and 16.4 dS/ m and the second factor and second factors were two genotypes (P.cineraria and P.juliflora). The results showed a gradual decrease in stem height, total leaf area, root and shoot dry weight and number of leaves per seedling of both species by increasing salinity of the root zone. Low salinity levels (5.8 dS/ m) do not cause a substantial inhibition of growth, but increasing the salt concentration gradually reduces the vegetative characteristics. In both genotypes, proline, total nitrogen, Glycine betaine aldehyde and calcium (Ca) increased with increasing salt concentration. Also, these factors were significantly higher in Prosopis juliflora than Prosopis cineraria. Potassium (K), organic carbon (OC %), decreased significantly in both genotypes with increasing salt concentration. Glycine betaine aldehyde is one of the effective strategies in salt stress tolerance and increasing carbon storage in soil.