Acta Physiologiae Plantarum

Baha, Nassima

doi: 10.1007/s11738-021-03248-8pmid: N/A

This study was carried out to study the effects of single and combined inoculation of rhizobial strain and PGPR at varying ratios on Lucerne grown under salt stress. Germination, seedling growth parameters, organic solutes and mineral ions contents of the seedlings were assessed after nine days of sowing. Germination, length and vigor index did not significantly change after inoculation. In contrast, under saline stress, application of inoculums significantly enhanced the germination and growth parameters. In addition, germination was less affected by saline stress than seedling growth, since the levels of reduction in growth-related parameters are higher. The effect of bacterial inoculation was strain specific and ratio dependent. The single inoculation and co-inoculation at the ratio of 2/1 were more effective under salt stress than the other co-inoculations suggesting the existence of synergistic interactions between the used strains. In opposite, the co-inoculation at ratio 1/2 was more effective on germination in the absence of salt stress. The inoculated seedlings accumulated less sodium and chloride as well as they maintained the same levels of K+ content compared to non-inoculated ones. Organic solute levels were not significantly influenced by both salt and bacterial inoculation in most seedlings. These results suggest that the Lucerne salt tolerance strategy does not directly involve organic solutes. These results indicate that application of these strains could alleviate the deleterious effects of soil salinity on seedling germination and growth, suggesting that these strains may be used as bio-fertilizers to enhance alfalfa establishment in arid and semi-arid areas.

Huan, Yunmin; Yang, Liu; Liu, Qin; Lin, Lijin; Liao, Ming’an; Wang, Zhihui; Liang, Dong; Xia, Hui; Tang, Yi; Lv, Xiulan; Wang, Jin

doi: 10.1007/s11738-021-03247-9pmid: N/A

To study the effects of indole acetic acid (IAA) on the growth and selenium (Se) absorption of fruit tree, a pot experiment was conducted to study the effects of different concentrations involved in the spraying of 0 (the control), 30, 60, 90, and 120 mg/L IAA on the growth and Se uptake of C. betacea seedlings. The concentrations of 30, 60, and 90 mg/L IAA increased the various organs’ biomass and net photosynthetic rate of C. betacea seedlings compared to the control, while the concentration of 120 mg/L IAA had no significant effect on that. Only the concentration of 60 mg/L IAA increased the chlorophyll (chlorophyll a, chlorophyll b, total chlorophyll) contents in C. betacea seedlings compared to the control. The concentrations of 30, 60, and 90 mg/L IAA also increased the antioxidant enzymes’ (superoxide dismutase, peroxidase, and catalase) activities and soluble protein content of C. betacea seedlings compared to the control. For Se content, compared to the control, the concentrations of 60 and 90 mg/L IAA increased the Se contents in roots, stems, leaves, and shoots of C. betacea seedlings, and also enhanced the Se bioconcentration factor. Therefore, spraying IAA with the appropriate concentration (60–90 mg/L) could promote the C. betacea seedlings’ growth and Se absorption, and the best concentration was 60 mg/L IAA.

Unnikrishnan, Divya K.; Sreeharsha, Rachapudi V.; Reddy, Attipalli R.

doi: 10.1007/s11738-021-03245-xpmid: N/A

In the present study, we have analyzed the seed yield and seed quality of pigeonpea grown under elevated CO2. Pigeonpea was grown for its complete life cycle in open top chambers under elevated CO2 (600 µmol/mol) and atmospheric ambient CO2 (400 µmol/mol). The growth, biomass and seed yield were increased under elevated CO2 when compared to plants grown at ambient CO2 concentrations. The mature seeds were collected after 120 days for various biochemical analyses to determine their nutritional quality. The biochemical analyses indicated that elevated CO2 grown pigeonpea seeds did not show any significant decrease in nitrogen and protein contents but showed an increase in total carbohydrates. The metabolomics of seeds revealed changes in sugars, amino acids, organic acids and fatty acid levels under elevated CO2 growth. The seeds collected from elevated CO2 grown pigeonpea showed higher levels of essential amino acids inferring their better nutritional quality. The total proteome of pigeonpea seed was studied through label-free quantification and recorded an increase in several seed specific proteins including certain stress related proteins in elevated CO2 grown pigeonpea seeds. The proteome and metabolome data demonstrate better seed vigor in elevated CO2 grown pigeonpea.

Rádi, Feríz; Nagy, Bettina; Ferenc, Györgyi; Török, Katalin; Nagy, István; Zombori, Zoltán; Dudits, Dénes; Ayaydin, Ferhan

doi: 10.1007/s11738-021-03252-ypmid: N/A

Genome-editing tools from Oligonucleotide-Directed Mutagenesis (ODM) to CRISPR system use synthetic oligonucleotides for targeted exchange of nucleotides. Presently, majority of genome-editing protocols are dependent on the in vitro cell or tissue culture systems with somaclonal variation, and limitations in plant regeneration. Therefore, here, we report an alternative in planta cellular test system for optimization of the ODM, based on the injection of oligonucleotide solution into the apical meristematic region of haploid maize seedlings. Using 5′-fluorescein-labeled oligonucleotides, we detected accumulation of synthetic DNA molecules in cells of the shoot apical meristem and of the vascular bundles of leaf primordia. For silencing or knocking down of the phytoene desaturase gene in somatic cells, 41-mer long single-stranded oligonucleotides with TAG stop codon were injected into maize seedlings. We detected out-growing M1 plantlets that developed leaves with white stripes or pale-green color. Confocal microscopy of white stripes showed that in addition to the chlorophyll fluorescence-deficient tissue region, chlorophyll containing cells are present in white stripes. The Ion Torrent sequencing of DNA samples from the white stripes indicated 0.13–1.50% read frequency for the TAG stop codon in the phytoene desaturase gene. Appearance of chlorotic abnormalities supports the mutagenic nature of oligonucleotide molecules after injection into the shoot apical meristem region of maize seedling. The described protocol provides basis for early seedling stage characterization of functionality of a mutagenic oligonucleotide with different chemistry and testing efficiency of various treatment combinations at plant level.

Marques Fonseca, Maira Christina; de Ávila, Mariane Borges Rodrigues; Coutinho, Ítalo Antônio Cotta; das Dôres, Rosana Gonçalves Rodrigues; Meira, Renata Maria Strozi Alves; Silva, Andréia Fonseca

doi: 10.1007/s11738-021-03241-1pmid: N/A

Mikania laevigata leaves are used worldwide as herbal medicines. Our study investigates the production differences among three different genotypes of this herb: the genotypes’ influence on the essential oil yield, chemical composition, and the plant tissues involved in the secretion of the chemical compounds produced by the leaves. The study performed the analysis during the summer and winter seasons. Plants were grown under an organic cultivation system in Oratórios, Minas Gerais, Brazil. Essential oils were extracted by hydrodistillation and analyzed by gas chromatography/mass spectrometer. The analysis highlighted substantial genetic variability among the genotypes. The genotype CENARGEN showed higher biomass production, oil yield, and a high concentration of major constituents detected by chromatographic analysis in essential oils, such as germacrene D and caryophyllene oxide. The season affected the chemical composition of the essential oils. Germacrene D and bicyclogermacrene were the major constituents in the winter-essential-oils; spatulenol and caryophyllene oxide were the major constituents in the summer-essential-oils.

Wang, Limin; Yu, Boyang; Zhao, Yanan; Li, Yongzhou; Guo, Jing; Zhu, YuanDi

doi: 10.1007/s11738-021-03243-zpmid: N/A

Columnar apples are a labor saving and productive tree form that has long been of interest to apple breeders and producers. MdCo31, which encodes a putative 2OG-Fe(II) oxygenase, is a potential candidate gene involved in controlling the internode length of columnar growth of apple. In this study, a putative regulation in internode length was conducted by exogenous application of GA3 and paclobutrazol. The results showed that the MdCo31-GFP fusion protein was specifically localized in the cytoplasm. Heterologous over-expression of MdCo31 in tobacco produced stunted phenotypes with high chlorophyll content in leaves, and delayed the timing of seed germination and flowering. The over-expression tobacco plants were more sensitive to exogenous application of GA3 but insensitive to paclobutrazol, and their growth correlated to lower concentrations of endogenous GA1 and lower expression levels of the gibberellin-regulated family gene NtGASA6. The higher the MdCo31 expression levels were identified in more dwarf transformants with the shorter internodes. This research proposed that the decrease in endogenous GA1, resulting from high MdCo31 expression, induced dwarf phenotypes and shorted internodes, which indicated that MdCo31 is responded to gibberellins’ deficiency conferring the internodal growth of columnar apples.

Ikkonen, Elena; Chazhengina, Svetlana; Butilkina, Marina; Sidorova, Valeria

doi: 10.1007/s11738-021-03239-9pmid: N/A

The application of carbon-rich substrates to agricultural soils is discussed as a strategy to improve soil properties and fertility, which can affect plant physiological traits and enhance agricultural crop yield. The aim of this study was to evaluate if shungite, carbon-rich sedimentary-volcanic rock, may improve plant ecophysiological traits under sufficient water supply as well as soil water deficit. A pot culture experiment was conducted with onion (Allium cepa L.) seedlings, using four shungite concentrations (0, 5, 10 and 20 g kg−1) in an Umbric Podzols and two water regimes: well-watered and drying-wetting cycles. Soil water deficit decreased root nutrient content, depressed seedlings growth, net CO2 assimilation rate (An), stomatal conductance (gs) and the respiration rates in both darkness (Rd) and the light (Rl), but increased water use efficiency (WUE) at leaf level. Shungite application decreased the leaf necrosis under both water regimes and increased total leaf length of DW seedlings. Compared with the well-watered conditions, under drying-wetting cycle shungite stimulated the increase of the An rate and WUE at low measurement temperature. No significant effect of shungite was found for Rd, Rl, Rl/Rd, Rd/Ag (Ag = An + Rl) and Rl/Ag regardless soil water regimes. Shungite application was not so successful to eliminate the negative effects of soil water deficit on growth and physiological processes of A. cepa. The observed positive effects of shungite on the physiological traits of onion seedlings were more likely associated with the increase in the content of nutrients than with the improvement in soil water properties.

El-Sheekh, Mostafa M.; Prášil, Ondřej; El-Mohsnawy, Eithar

doi: 10.1007/s11738-021-03242-0pmid: N/A

The iron in cyanobacterial cells contributes to energy conversion via electron transport chains, so its availability directly influences all metabolic pathways. Besides exploring cell adaptations and changes occurring with iron insufficient stress, the present work examines profoundly for the first time the metabolic changes accompanied with iron recovery for the thermophilic cyanobacterium Synechococcus elongatus (Näg., var. thermalis Geitl. Strain Kovrov 1972/8). S. elongatus cells were cultivated on two iron deprivation levels, iron-limited (45 nM Fe) and iron-deficient (4.5 nM Fe). Growth, carotenoids/Chlorophyll-a (Car/Chl-a) ratio, transmitting electron images, pigments fractionation analysis, and cell activity were checked. The obtained results demonstrated an astounding decrease in Chl-a content, an increment in β-carotene content, leading to rising the Car/Chl-a ratio, a reduction of phycobilins content, a reduction in cell diameters, a decrease of energy transfer, a depletion of the electron transport chain, and a reduction of photosynthesis and respiration processes under inadequate iron condition. Likewise, the photochemical activity of photosystem II (PSII), determined by Fv/Fm ratio and thermoluminescence estimations, demonstrated that PSII was disabled under iron pressure. With iron recovery by 200 nM Fe, cells regained full metabolic activity within 24 h. Despite the fact that photosynthesis and respiration activity exhibited nearly a similar behavior, S. elongatus under iron-deficiency began to recuperate the activity of the photosynthetic apparatus quicker than the respiratory machinery by regaining their pigment content and activity.

Lu, Qi-Huan; Wang, Ya-Qi; Xu, Jin-Peng; Cai, Xian-Yun; Yang, Hong-Bing

doi: 10.1007/s11738-021-03238-wpmid: N/A

Salt-tolerant variety Chuanqiao No. 1 and salt-sensitive variety Chuanqiao No. 2 of Tartary buckwheat were used as experimental materials, and the effect of different concentrations of ABA on physiological characteristics of Tartary buckwheat under salt stress and the optimal ABA concentration on expression of salt tolerance-related genes were analyzed. The results showed that the ABA treatment with appropriate concentration improved the stress resistance of Tartary buckwheat seedlings, and the optimal ABA concentration varies in Chuanqiao No. 1 and Chuanqiao No. 2 with 30 and 20 μM. Under salt stress, the ABA treatment with appropriate concentration increased the fresh weight, root vigor of seedlings and leaf SOD, POD, and CAT activity of Tartary buckwheat, and reduced the leaf plasma membrane permeability of Tartary buckwheat, and the optimal ABA concentration under salt stress varies in Chuanqiao No. 1 and Chuanqiao No. 2 with 40 and 10 μM. The ABA treatment with optimal concentration promoted the expression of FtNHX1, FtSOS1, potassium channel, and four ABA receptor-related genes in the stem and root of two Tartary buckwheat varieties. The expression of salt tolerance-related genes is consistent with the improvement of physiological characteristics in Tartary buckwheat.

Golkar, Pooran; Hamzeh, Esmaeil; Mirmohammadi Maibody, Seyed Alimohammad; Taghizadeh, Marzieh

doi: 10.1007/s11738-021-03254-wpmid: N/A

Drought is a main stressor affecting plant production worldwide. Safflower (Carthamus tinctorius L.) is known to exploit biochemical strategies to tolerate drought stress. However, the little so far known about these strategies does not guarantee safflower yield stability in future. To fill the gap, changes in the biochemical traits and antioxidant activities of safflower were monitored using 100 genotypes under the two non-stress and drought-stress field conditions in two subsequent years (2017 and 2018). While drought stress was observed to give rise to reversible increases in total phenolics (TPC), total flavonoids (TFD), total flavonols (TFL), total anthocyanin (Ant), proline, malondialdehyde (MDA), and antioxidant activity, it decreased total chlorophyll (ChlT) and total carotenoid (Car) contents in safflower. Under drought stress, the highest values for TPC (21.55 16.07 mg GAEg−1 fresh weight [FW]), Car (0.08 mg g−1 FW), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity (98%) were measured in G16, averaged over the two study years. Also the highest values for TFD (5.17 mg QEg−1 FW), TFL (1.99 mg QEg−1 FW), Ant (234.1 µmol g−1 FW), ChlT (0.67 mg g−1 FW), and proline (851 μmol g −1 FW) were recorded for G80, G60, G23, G62, and G33. The least MDA content (2.8 µmol g−1 FW) was denoted to G91 under drought stress. The results of both principal component and correlation analyses demonstrated the effective role of total flavonoids in safflower drought tolerance. The high genetic variance was seen to result in the high heritability of biochemical traits under drought stress, thereby improving drought tolerance in safflower cultivated in drought prone regions. The significant genetic variations in all the biochemical traits indicated that these traits, especially TPC and TFD, could be used as screening criteria for genotypic selection in arid climates.