Efficient protocols, safe from somaclonal variation, were developed for regeneration of Iris sibirica plants via organogenesis and somatic embryogenesis from leaf-base explants cultivated on Murashige and Skoog media supplemented with thidiazuron (TDZ, 1.0mg/l) or 2,4-dichlorophenoxyacetic acid (2,4-D, 1.0mg/l). The morphogenic response and callus formation efficiency differed significantly between 2,4-D (80.9%) and TDZ (67%) morphogenesis induction treatments. TDZ induced only organogenic calli, while calli obtained with 2,4-D were composed of three types differing in color and consistency: white, friable — embryogenic calli (4.5%, 3.8mg/explant), green, compact — organogenic calli (12.4%, 48.4mg/explants) and yellow — non-regenerative calli (77.3%, 254.4mg/explant). The cultivation of embryogenic calli on medium with 2,4-D and Kinetin resulted in further development of somatic embryos (54embryos/g of calli) which germinated with a frequency of 62% after being transferred to a medium without plant growth regulators. Stable shoot cultures were established by transferring organogenic calli with shoot primordia to media with 0.1mg/l α-naphthaleneacetic acid (NAA) and 1.0mg/l 6-benzylaminopurine (BA), while further cultivation on media of the same composition (TDZ or 2,4-D) resulted in the reduced growth and rhizogenesis, respectively. The TDZ induction treatment resulted in higher number of shoots per explant (7.9) than the 2,4-D treatment (4.3). After successful rooting and ex vitro acclimatization, plants were grown in the field and flowered to seed production. Flow cytometry, chromosome counting and random amplification of polymorphic DNA (RAPD) analysis indicated no evidence of genetic variation in plants regenerated via somatic embryogenesis or organogenesis. The results suggest that established protocols are safe for use in genetic transformation procedures or large-scale production of true-to-type I. sibirica plants

Drought stress affects plant growth and development through several mechanisms, including the induction of oxidative stress. To cope with drought, plants have drought tolerance mechanisms at the physiological, biochemical, and molecular levels. In this study, the effects of foliar application of distilled water and methyl jasmonate (MeJA) (5 and 50 µM) on the physiological, biochemical, and molecular responses of Impatiens walleriana during two drought regimes (15 and 5% soil water content, SWC) were investigated. The results showed that plant response depended on the concentration of the elicitor and the stress intensity. The highest chlorophyll and carotenoid contents were observed at 5% SWC in plants pre-treated with 50 µM MeJA, while the MeJA did not have a significant effect on the chlorophyll a/b ratio in drought-stressed plants. Drought-induced formation of hydrogen peroxide and malondialdehyde in plants sprayed with distilled water was significantly reduced in plant leaves pretreated with MeJA. The lower total polyphenol content and antioxidant activity of secondary metabolites in MeJA-pretreated plants were observed. The foliar application of MeJA affected the proline content and antioxidant enzyme activities (superoxide dismutase, peroxidase, and catalase) in plants that suffered from drought. The expression of abscisic acid (ABA) metabolic genes (IwNCED4, IwAAO2, and IwABA8ox3) was the most affected in plants sprayed with 50 µM MeJA, while of the four analyzed aquaporin genes (IwPIP1;4, IwPIP2;2, IwPIP2;7, and IwTIP4;1), the expression of IwPIP1;4 and IwPIP2;7 was strongly induced in drought-stressed plants pre-treated with 50 µM MeJA. The study’s findings demonstrated the significance of MeJA in regulating the gene expression of the ABA metabolic pathway and aquaporins, as well as the considerable alterations in oxidative stress responses of drought-stressed I. walleriana foliar sprayed with MeJA. The results improved our understanding of this horticulture plant’s stress physiology and the field of plant hormones’ interaction network in general.

The rapid production and numerous applications of nanomaterials warrant the necessity and importance of examining nanoparticles in terms to their environmental and biological effects and implications. In this study, the effects of a water-soluble hyper-harmonized hydroxyl-modified fullerene (3HFWC) on cherry tomato seed germination, seedlings growth, physiological response and fruiting was evaluated. Changes in the photosynthetic pigments content, oxidative stress assessment, and aquaporin genes expression in cherry tomato plants were studied after during short- and long-term continuous exposure to 3HFWC nanosubstance (200 mg/L). Increased levels of photosynthetic pigments in leaves, lycopene in fruits, decreased levels of hydrogen peroxide content, activation of cellular antioxidant enzymes such as superoxide dismutase, catalase and peroxidase and increased aquaporin gene expression (PIP1;3, PIP1;5 and PIP2;4) were observed in 3HFWC nanosubstance-exposed plants in comparison to control, untreated cherry tomato plants. The 3HFWC nanosubstance showed positive effects on cherry tomato seed germination, plantlet growth and lycopene content in fruits and may be considered as a promising nanofertilizer.

This study was carried out to examine the drought effect on development, physiological, biochemical and molecular parameters in Impatiens walleriana grown ex vitro. Experiment design included three treatments: Control plants—grown under optimal watering (35%–37% of soil moisture content), drought-stressed plants—non-irrigated to reach 15% and 5% of soil moisture content and recovery plants—rehydrated for four days to reach optimal soil moisture content. Drought reduced fresh weight, total leaf area, as well as dry weight of I. walleriana shoots. Drought up-regulated expression of abscisic acid (ABA) biosynthesis genes 9-cis-epoxycarotenoid dioxygenase 4 (NCED4) and abscisic aldehyde oxidase 2 (AAO2) and catabolic gene ABA 8′-hydroxylase 3 (ABA8ox3) which was followed by increased ABA content in the leaves. Decrement in water potential of shoots during the drought was not accompanied with increased amino acid proline content. We detected an increase in chlorophyll, carotenoid, total polyphenols and flavonols content under drought conditions, as well as malondialdehyde, hydrogen peroxide and DPPH (1,1′-diphenyl-2-picrylhydrazyl) activity. Increased antioxidant enzyme activities (superoxide dismutase, peroxidase and catalase) throughout drought were also determined. Recovery treatment was significant for neutralizing drought effect on growth parameters, shoot water potential, proline content and genes expression.