Response of morphological and biochemical traits and transcriptomic of CDPKs and P5CS Genes to phytohormones and nutrients in two bread wheat germplasms under salinity conditions

Several enzymes play an important role in the biosynthesis of osmolyte in plants. The main objective of this work is to study the effects of salt stress, kinetin+potassium and giberellic acid+potassium on calcium-dependent protein kinases (CDPKs) and delta-1-pyrroline-5- carboxylate synthase (P5CS) genes expression of two bread wheat varieties. The results shodwe that, salts stress reduced the plant growth of the two wheat germplasms. Moreover, the addition of kinetin+ potassium improved the performance of morphometric parameters while the addition of giberellic acid +potassium has less effect. On the biochemical level, results indicated that salt stress increased the proline contents compared with control plants. Extra increase in proline contents was recorded by kinetin+ potassium, while the treatment of giberellic acid +potassium showed almost similar results as in salt stress only. On the molecular level, salt stress, kinetin and giberellic acid significantly increased the two genes expression of CDPKs and P5CS with more effect in presence of kinetin+ potassium.

THE EFFECT of GA3 AND SALINITY on GROWTH of ROSELLE (Hibiscus sabdariffa L.)

In order to alleviate the deleterious effects of salinity, different types of phytohormones have been used. Among them, GA3 has been the main focus of some plant scientists. This study aimed to evaluate the effect of gibberellic acid and salinity on growth and production of roselle (Hibiscus sabdariffa L). This research was conducted in a greenhouse of Agriculture Faculty, University of Sumatera Utara, Medan. The study used utterly randomized design with two factors. The first factor was gibberellic acids. They were gibberellic acid (5 mg L-1) and no gibberellic acid. The second factor was salinity. They were 0 dsm-1 and 4-5 dsm-1. The interaction between gibberellic acid and salinity acid indicated a significant effect on the percentage of germination, chlorophyll a and b and beta-carotene. The application of giberellic acid helped in the tolerance of plants to salinity. Thus, application of GA3 become essential to improve overall productivity in salinity.

Identification, characterization, and expression profiles of the GASA genes in cotton

Background GASA (Giberellic Acid Stimulated in Arabidopsis) gene family plays a crucial role in the phytohormone signaling pathway, growth and development, and stress responses in plants. Many GASA homologs have been identified in various plants. Nevertheless, little is known about these proteins in cotton. Results In the current study, we identified 19, 17, 25, 33, and 38 GASA genes via genome-wide analyses of Gossypium herbaceum, G. arboreum, G. raimondii, G. barbadense, and G. hirsutum, respectively, and performed comprehensive bioinformatics and expression analyses. According to our results, 132 GASA proteins shared similar protein structures and were classified into four groups based on the phylogenetic tree. A synteny analysis suggested that segmental duplication was a key driver in the expansion of the GASA gene family. Meanwhile, the cis-element and protein interaction analyses indicated that GhGASA proteins play a significant role in the hormone responses. Transcriptomic and qRT-PCR (Quantitative real time-polymerase chain reaction) analyses revealed diverse expression profiles of the GhGASA genes in different organs under abiotic stresses, indicating that some GhGASA genes possibly participate in fiber development and abiotic-stress responses. Conclusions The GASA genes in cotton were systematically identified and analyzed for the first time in this paper, and it suggested that the GASA genes are important to the development and growth of cotton. These results will support future exploration of the functions of GASA genes in cotton.

Influence of different environmental conditions and giberellic acid treatment on flowering time of divergent genotypes of cabbage (Brassica oleracea var. capitata L.) and their F1 hybrids

In the process of cabbage breeding and seed production, one of the most important characteristics is the time of flowering. In order to investigate the influence of genotype, season and term of sowing on the flowering process, as well as the genetic control of this trait, an experiment was conducted with three genotypes of cabbage N, B and Scc of different geographical origin and different vegetation length, as well as three new F1 hybrids N x Scc , B x Scc and B x N obtained by hybridization between genotypes. The experiment was conducted during three temperature different seasons S1, S2 and S3 (average cold, cold and warm seasons), in three different sowing terms: August 15 (I), September 1 (II) and September 15 (III). During the winter period favorable for vernalization, two treatments with 300 ppm GA3 were performed. A statistically significant influence of all examined factors: genotype, year, sowing term and gibberellin GA3 treatment, on flowering time was determined. AMMI analysis determined the degree of adaptability of genotypes depending on the growing season, sowing terms and GA3 treatment for the trait time of flowering. The highest stability based on ASV values for flowering time was shown by hybrid BxN and its parental component genotypes B and N, while the hybrid Scc x B proved to be the most unstable in terms of flowering time. The pattern of relative expression of the most important flower repressor BoFLC2 gene showed a certain correlation with the flowering time of genotypes. The lowest quantitative expression of this gene was found in genotype B and it had the earliest flowering in all seasons, while genotype N had the highest relative expression of the BoFLC2 locus and the latest flowering.

Enhanced germination performance of dormant seeds of Eragrostis tef in the presence of light

Lack of germination or low germination due to seed dormancy prevents successful crop establishment in several important plants. To determine the presence of innate seed dormancy and effects of stress-related plant hormones on germination performance of Teff (Eragrostis tef) seeds, we primed seeds in 1% KNO3 for 24 hours in dark conditions at 21 ± 0.5 ºC along with varying concentrations of chemicals known to influence seed germination, including: acetyl salicylic acid (ASA); methyl jasmonate (JA-Me); giberellic acid (GA3); and indole acetic acid (IAA). Primed seeds were incubated either in constant light (210 µM/m2/s) or in darkness at 21 ± 0.5 ºC. The results indicated that primingsignificantly improved final germination percentage (FGP) in both light (92.5%) and dark (89.4%) conditions compared with untreated seeds. The inclusion of plant hormones in the priming media generally had limited effects, except for 10 mM ASA (94.5%) and 100 mM GA3 (92.5%). ASA generally provided faster seed germination than seeds primed in 1% KNO3 only, while the other plant hormones had no effect on the time required for 50% of FGP in the dark. Priming had no significant effect on time span of germination in either light or dark incubation conditions. The results demonstrate that E. tef has light-inducible seed germination and about half of freshly harvested seeds can be dormant, which can be eliminated to some extent by priming seeds in 1% KNO3.

Giberellic Acid in the Expansion of the Thermal Range of Lettuce Seeds

Lettuce presents an increasing demand, which makes necessary the expansion of the areas destined to its planting. Temperature is a limiting factor, because it acts directly on germination, where changes and adjustments in the hormonal balance, mainly of gibberellin (GA) and abscisic acid (ABA), occur. The objective of this study was to evaluate if the treatment of seeds with gibberellic acid is capable of mitigating the damages caused by high temperatures. The seeds were submitted to germination test, first count, percentage of abnormal seedlings and analysis of shoot and root growth. The treatments consisted of seven concentrations of gibberellic acid (control—not treated with GA, 25 mg L-1, 50 mg L-1, 75 mg L-1, 100 mg L-1, 125 mg L-1, 150 mg L-1) and three constant temperatures (25, 30 and 35 °C). The germination and first count, when submitted at 25 and 30 °C presented an increase up to 50 mg L-1 of GA, while at 35 °C the growth was constant up to 125 mg L-1 of GA. Treatment with GA increased root and shoot length. Giberelic acid mitigated the damage caused to lettuce seeds when subjected to temperatures above the optimum.

Influence of plant growth regulators on yield and yield components in pigeonpea

Pigeonpea is an important pulse crop and one of the major sources of protein in India. In the present study, investigations were undertaken to study the role of foliar spray of different plant growth regulators (PGRs) in altering morphology and enhancing the yield potential of pigeonpea varieties VBN 1, APK 1 and VRG 62. Among different plant growth regulators (PGRs) studied, foliar application of Giberellic acid (GA3) significantly increased plant height, number of leaves and branches in pigeonpea. This was followed by Brassinosteroid (BR). Foliar application of PGRs significantly increased both the growth attributes and yield. Various yield components viz., days to 50 per cent flowering, days to maturity, number of flowers per plant, number of pods per plant, number of clusters per plant, number of seeds per pod, hundred seed weight and harvest index were enhanced by PGR application. Maximum dry matter accumulation and fertility co-efficient was recorded in the treatment (T9), i.e., BR application @ 0.1 ppm than the other treatments. It is concluded that foliar application of BR @ 0.1ppm is advantageous in enhancing both growth and yield of Pigeonpea and thus BR foliar spray can be recommended for adoption by the farmers, to maximize the yield in Pigeonpea.

Attenuation of low-temperature stress in rice seedlings

ABSTRACT Rice is a cold-sensitive crop, and its exposure to low-temperature stress, during germination and early seedling growth, can negatively affect the initial stand establishment. Substances that act as growth regulators can be used to mitigate this initial stress. Thus, the influence of gibberellic acid, thiamethoxam and a phytohormone was investigated at the growth variables and antioxidant enzyme activity of the 'Irga 424' and 'Puita Inta CL' rice cultivars, at low-temperature (17 ºC). The products act on the germination percentage of 'Puita Inta CL', but vigor is only influenced by giberellic acid. Giberellic acid influences shoot length, irrespective of cultivar, while thiamethoxam and the phytohormone only affect length in 'Puita Inta CL'. The antioxidant activity depends on the cultivar and organ tested (shoot or root). These products mitigate the effects of cold, thereby preventing the formation of reactive-oxygen species and lipid peroxidation, and positively influence the superoxide dismutase enzyme activity.