The effects of nitrogen and potassium nutrition on the growth of nonembryogenic and embryogenic tissue of sweet orange (Citrus sinensis (L.) Osbeck)

Somatic embryogenesis and β-glucuronidase transformation in chickpea (Cicer arietinum cv. Bivanich)

BACKGROUND

Chickpea (Cicer arietinum L.) is an important kernel legume in the world. To optimize the plant tissue culture some experiments such as direct regeneration, proliferation, rooting shoots and somatic embryogenesis were done.

METHODS AND RESULTS

In experiments were used direct regeneration and proliferation, various levels of plant growth regulators NAA (0 and 1.0 mg/l), BAP (0, 1, 3 and 5 mg/l) and three explants' types (epicotyl, cotyledon and embryonic axis). The results of both experiments showed that embryonic axis explant was better than other explants. The highest percentage was obtained in MS media containing 1 mg/l BAP and also 3 mg/l BAP and 0.1 mg/l NAA with an average of 72%. The highest average number of branches (4.66) was found in the proliferation of embryonic axis in MS medium containing 3 mg/l BAP. The highest rooting shoot (90%) was found in 1/2MS in B5 medium vitamins with 0.2 mg/l of IBA and 0.5 mg/l NAA. Somatic embryogenesis experiments were compared on the concentration gradient of 2,4-D in fine embryonic axis explants. The results displayed that the concentration gradient of 10 mg/l 2,4-D to 5 mg/l of 2,4-D and then to zero concentration showed the highest number of embryos.

CONCLUSION

The best environment for regeneration embryos was MS medium with 2.5 mg/l of 2,4-D concentration gradient to zero. In this study, the PCR reaction showed the presence of the β-glucuronidase (gus) marker gene in regenerated cotyledons for 20 min in all three strains studied.

Optimization of Biomass Accumulation and Production of Phenolic Compounds in Callus Cultures of Rhodiola rosea L. Using Design of Experiments

Rhodiola rosea L. is a valuable medicinal plant with adaptogenic, neuroprotective, antitumor, cardioprotective, and antidepressant effects. In this study, design of experiments methodology was employed to analyze and optimize the interacting effects of mineral compounds (concentration of NO₃⁻ and the ratio of NH₄⁺ to K⁺) and two plant growth regulators [total 6-benzylaminopurine (BAP) and α-naphthylacetic acid (NAA) concentration and the ratio of BAP to NAA] on the growth and the production of total phenolic compounds (TPCs) in R. rosea calluses. The overall effect of the model was highly significant (p < 0.0001), indicating that NH₄⁺, K⁺, NO₃⁻, BAP, and NAA significantly affected growth. The best callus growth (703%) and the highest production of TPCs (75.17 mg/g) were achieved at an NH₄⁺/K⁺ ratio of 0.33 and BAP/NAA of 0.33, provided that the concentration of plant growth regulators was 30 μM and that of NO₃⁻ was ≤40 mM. According to high-performance liquid chromatography analyses of aerial parts (leaves and stems), in vitro seedlings and callus cultures of R. rosea contain no detectable rosarin, rosavin, rosin, and cinnamyl alcohol. This is the first report on the creation of an experiment for the significant improvement of biomass accumulation and TPC production in callus cultures of R. rosea.

Callus induction and regeneration in sugarcane under drought stress

Tissue culture methods are useful in assessing the tolerance of various stresses due to the ease of controlling stress under in vitro conditions. This study aimed to investigate the response of sugarcane genotyps to drought stress using calli as a model system. For inducing sugarcane callus, the medium of Murashige and Skoog (MS) was used with different mannitol concentrations (100, 200, and 300 mM) to measure their effects on callus frequency, the day of callus initiation, embryogenic potential, relative growth rate (RGR), water and proline contents, K+ and Na+ contents, as well as the formation of shoot and roots for three sugarcane genotypes (e.g., GT 54-9, G 84-47, and pH 8013). The RAPD-PCR analysis was carried out using five oligonucleotide primers to identify the genetic variation among sugarcane genotypes. The results indicated that the degree of callus proliferation varied from 70 - 86%. The highest value of callus proliferation, PGR, shoot formation was recorded for the genotype GT 54-9 compared to the other two genotypes (G 84-47 and pH 8013). Calli treated with 100 mM mannitol showed the highest RGR, proline and waer contents for the genotype GT 54-9, while, those treated with 300 mM recorded the lowest values of these parameters for the genotype pH 8013. The genotype G 84-47 collected highest Na+ content, while the genotype pH 8013 collected highest K+ content. The results of this study recommend preference for GT 54-9 genotype, which is considered the most promising genotype, showing more tolerance to drought stress based on all studied traits.

Introducing a hybrid artificial intelligence method for high-throughput modeling and optimizing plant tissue culture processes: the establishment of a new embryogenesis medium for chrysanthemum, as a case study

Data-driven models in a combination of optimization algorithms could be beneficial methods for predicting and optimizing in vitro culture processes. This study was aimed at modeling and optimizing a new embryogenesis medium for chrysanthemum. Three individual data-driven models, including multi-layer perceptron (MLP), adaptive neuro-fuzzy inference system (ANFIS), and support vector regression (SVR), were developed for callogenesis rate (CR), embryogenesis rate (ER), and somatic embryo number (SEN). Consequently, the best obtained results were used in the fusion process by a bagging method. For medium reformulation, effects of eight ionic macronutrients on CR, ER, and SEN and effects of four vitamins on SEN were evaluated using data fusion (DF)-non-dominated sorting genetic algorithm-II (NSGA-II) and DF-genetic algorithm (GA), respectively. Results showed that DF models with the highest R² had superb performance in comparison with all other individual models. According to DF-NSGAII, the highest ER and SEN can be obtained from the medium containing 14.27 mM NH₄⁺, 38.92 mM NO₃^-, 22.79 mM K⁺, 5.08 mM Cl^-, 3.34 mM Ca²⁺, 1.67 mM Mg²⁺, 2.17 mM SO₄^2-, and 1.44 mM H₂PO₄^-. Based on the DF-GA model, the maximum SEN can be obtained from a medium containing 0.61 μM thiamine, 5.93 μM nicotinic acid, 0.25 μM biotin, and 0.26 μM riboflavin. The efficiency of the established-optimized medium was experimentally compared to Murashige and Skoog medium (MS) for embryogenesis of five chrysanthemum cultivars, and results indicated the efficiency of optimized medium over MS medium.Key points• MLP, SVR, and ANFIS were fused by a bagging method to develop a data fusion model.• NSGA-II and GA were linked to the data fusion model for establishing and optimizing a new embryogenesis medium.• The new culture medium (HNT) had better efficiency than MS medium.

Interactive effects of nitrogen and potassium on photosynthesis and photosynthetic nitrogen allocation of rice leaves

BACKGROUND

Nitrogen (N) and potassium (K) are two important mineral nutrients in regulating leaf photosynthesis. Studying the interactive effects of N and K on regulating N allocation and photosynthesis (P_n) of rice leaves will be of great significance for further increasing leaf P_n, photosynthetic N use efficiency (PNUE) and grain yield. We measured the gas exchange of rice leaves in a field experiment and tested different kinds of leaf N based on N morphology and function, and calculated the interactive effects of N and K on N allocation and the PNUE.

RESULTS

Compared with N0 (0 kg N ha^- 1) and K0 (0 kg K₂O ha^- 1) treatments, the P_n was increased by 17.1 and 12.2% with the supply of N and K. Compared with N0K0 (0 kg N and 0 kg K₂O ha^- 1), N0K120 (0 kg N and 120 kg K₂O ha^- 1) and N0K180 (0 kg N and 180 kg K₂O ha^- 1), N supply increased the absolute content of photosynthetic N (N_psn) by 15.1, 15.5 and 10.5% on average, and the storage N (N_store) was increased by 32.7, 64.9 and 72.7% on average. The relative content of N_psn was decreased by 5.6, 12.1 and 14.5%, while that of N_store was increased by 8.7, 27.8 and 33.8%. Supply of K promoted the transformation of N_store to N_psn despite the leaf N content (N_a) was indeed decreased. Compared with N0K0, N180K0 (180 kg N and 0 kg K₂O ha^- 1) and N270K0 (270 kg N and 0 kg K₂O ha^- 1), K supply increased the relative content of N_psn by 17.7, 8.8 and 7.3%, and decreased the relative content of N_store by 24.2, 11.4 and 8.7% respectively.

CONCLUSIONS

This study indicated the mechanism that K supply decreased the N_a but increased the N_psn content and then increased leaf P_n and PNUE from a new viewpoint of leaf N allocation. The supply of K promoted the transformation of N_store to N_psn and increased the PNUE. The decreased N_store mainly resulted from the decrease of non-protein N. Combined use of N and K could optimize leaf N allocation and maintain a high leaf N_psn content and PNUE.

Transcriptional profiling of genes involved in embryogenic, non-embryogenic calluses and somatic embryogenesis of Valencia sweet orange by SSH-based microarray

Somatic embryogenesis (SE) is a most promising technology that is used for in vitro germplasm conservation and genetic improvement via biotechnological approaches in citrus. Herein, three suppression subtractive hybridization (SSH) libraries were constructed using calluses of Citrus sinensis cv. 'Valencia' to explore the molecular mechanisms that underlie the SE in citrus. A total of 880 unisequences were identified by microarray screening based on these three SSH libraries. Gene ontology analysis of the differentially expressed genes indicated that nucleolus associated regulation and biogenesis processes, hormone signal transduction, and stress factors might be involved in SE. Transcription factors might also play an important role. LEC1/B3 domain regulatory network genes (LEC1, L1L, FUS3, ABI3, and ABI5) were isolated in citrus SE. Some new transcription factors associated with citrus SE, like a B3 domain containing gene and HB4, were identified. To understand the influence of these isolated genes on SE competence, their expression profiles were compared among callus lines of seven citrus cultivars with different SE competence. The expression dynamics suggested that these genes could be necessary for the SE initiation and might play a role in embryogenic competence maintenance in different cultivars. On the basis of gene expression profiles, an overview of major physiological and biosynthesis processes at different developmental stages during citrus SE is presented. For the first time, these data provide a global resource for transcriptional events important for SE in citrus, and the specific genes offer new information for further investigation on citrus SE maintenance and development.

In vitro shoot growth of Brugmansia × candida Pers

The objective of this study was to improve the growth of in vitro shoot cultures of Brugmansia × candida 'Creamsickle'. Several mineral nutrient experiments were conducted to determine the effect of NH4 (+), NO3 (-), K(+), FeSO4/EDTA, ZnSO4, MnSO4, and CuSO4 on quality, leaf width and length, size and weight of shoot mass, and shoot number. The experiment to determine the levels of NH4 (+), NO3 (-), and K(+), was conducted as a 2-component NH4 (+): K(+) mixture crossed by [NO3 (-)] and resulted in an experimental design free of ion confounding and capable of separating the effects of proportion and concentration. The results of the NH4 (+)-K(+)-NO3 (-) experiment revealed a region in the design space where growth was significantly improved; the region generally had lower total nitrogen and lower NH4 (+):K(+) ratios than MS medium. The experiments to determine the appropriate levels of Fe, Zn, Mn, and Cu were conducted at six log levels ranging from 0 to 1 mM. Of the four metal salts tested, MnSO4 had the least effect on in vitro shoot growth and its concentration was reduced from 0.1 mM (MS level) to 0.001 mM. CuSO4 had large effects on in vitro shoot growth and was increased from 0.0001 mM to 0.001 mM. A 2-level factorial of NH4 (+)-K(+)-NO3 (-), FeSO4/EDTA, and ZnSO4 was conducted and several formulations identified for their improvements of quality and growth. In addition to the changes to MnSO4 and CuSO4, these formulations were characterized by lower levels of NH4 (+), K(+), NO3 (-) and Zn, and higher levels of FeSO4/EDTA. Overall, several nutrient formulations were identified as superior to MS medium for growth of in vitro shoot cultures of B. 'Creamsickle'.

Formulation of nutrient medium for in vitro somatic embryo induction in Plantago ovata forsk

A nutrient medium has been formulated by altering the macro- and micro-elemental concentration in the culture medium for in vitro somatic embryo induction of economically important medicinal plant Plantago ovata Forsk .A comparison was made between induced embryos with normal embryos (produced in Murashige and Skoog (MS) medium) to observe frequency of embryo induction and also to determine regeneration efficiency. In the present investigation, three different media have been formulated. Among them, FM3 (formulated media, treatment 3) was the most suitable for increasing the frequency of somatic embryo production and regeneration of P. ovata Forsk. Better result was obtained using formulated medium than with MS medium.

Sensory imbalance as mechanism of orientation disruption in the leafminer Phyllocnistis citrella: elucidation by multivariate geometric designs and response surface models

Experimental designs developed to address mixtures are suited ideally to many areas of experimental biology, including pheromone blend studies, because such designs address the confounding of proportionality and concentration intrinsic to factorial and one-factor-at-a-time designs. Geometric multivariate designs coupled with response surface modeling allowed us to identify optimal blends of a two-component pheromone for attraction and trap disruption of the leafminer moth, Phyllocnistis citrella, a major pest in citrus growing areas around the world. Field trials confirmed that the natural 3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal:(Z,Z)-7,11-hexadecadienal was most effective as an attractant for male moths. However, the response surface generated in mating orientation trials revealed that the triene component alone was more effective than the natural blend in disrupting trap catch. Each individual component was effective at disrupting orientation in field trials, but (Z,Z,E)-7,11,13-hexadecatrienal was approximately 13 times more effective, at the same concentration, compared with (Z,Z)-7,11-hexadecadienal alone. In addition, the application of geometric design and response surface modeling to field studies provided insight into a possible mechanism of mating disruption and supported sensory imbalance as the operating mechanism for this species.