Plant Growth Hormones and Micro-Tuberization in Breaking the Seed Dormancy of Bunium persicum (Boiss.) Fedts.

Bunium persicum is a valuable medicinal plant with limited production but high market demand. It thrives predominantly in high-altitude regions. The main challenges hindering its widespread cultivation are seed dormancy and a lengthy seed-to-seed cycle, making its large-scale cultivation difficult. Six genotypes of Bunium persicum were collected from different altitudes to evaluate its germination behavior and seed dormancy. The study was conducted during 2020-23 and comprised three experiments (viz., seed germination under an open field, controlled conditions, and micro-tuberization). Under open field conditions, germination percent was genotype dependent, and the highest germination percentage, root length, and shoot length were recorded in Shalimar Kalazeera-1. Germination behavior assessment of the Bunium persicum revealed that treatment T9 (GA3 (25 ppm) + TDZ (9 µM/L)) is effective in breaking the dormancy of Bunium persicum as well as in obtaining a higher germination percent for early development of the tubers. Similarly, with regard to the effect of temperature and moisture conditions, stratification under moist chilling conditions showed effectiveness in breaking seed dormancy as the germination percentage in stratified seeds was at par with the most efficient growth hormone. With regard to the in vitro micro-propagation, direct regeneration showed multiple shoot primordia at the base of the tubers without intervening callus phase from the MS medium supplemented with BA (22.2 µM) and NAA (13.95 µM) 4 weeks after sub-culturing. Similarly, medium supplemented with JA (8.0 mg/L) and BA (22.2 µM) produced well-organized somatic embryos with shiny surfaces, which appeared at the swelled basal portion of apical stems. Further, the combination of JA (6.0 mg/L) and BA (22.2 M) was effective in developing the micro-tubers and also enhanced the weight and length of Bunium persicum micro-tubers.

Impact of copper treatment on phenylpropanoid biosynthesis in adventitious root culture of Althaea officinalis L.

Althaea officinalis has been widely used in various pharmaceutical applications. The biological effects and significance of phenylpropanoids in numerous industries are well studied. However, fulfilling consumer demand for these commercially important compounds is difficult. The effect of heavy-metal toxic influence on plants is primarily due to a strong and rapid suppression of growth processes, as well as the decline in activity of the photosynthetic apparatus, also associated with progressing senescence processes. Some of the secondary metabolite production was triggered by the application of heavy metals, but there was not a stress response. In the adventitious root culture of A. officinalis, copper-mediated phenylpropanoid biosynthesis has been investigated in both concentration-and duration-dependent manners. High-performance liquid chromatography (HPLC) analysis revealed a total of nine different phenolic compounds in response to different concentrations of copper chloride. In this study, high productivity of phenolic compounds was observed in the copper chloride treated-adventitious root culture of A. officianalis. In particular, a low concentration of copper chloride led to a significant accumulation of phenolic compounds under optimal conditions. Moreover, all genes responsible for phenylpropanoid biosynthesis may be sensitive to phenolic compound production following copper treatment. Especially, the highest change in transcript level was observed from AoANS at 6 h. According to our findings, treatment with copper chloride (0.5 mM) for 48 or 96 h can be an appropriate method to maximize phenylpropanoid levels in A. officinalis adventitious root culture.

Silicon Confers Soybean Resistance to Salinity Stress Through Regulation of Reactive Oxygen and Reactive Nitrogen Species.

Salt stress is one of the major abiotic stressors that causes huge losses to the agricultural industry worldwide. Different strategies have been adopted over time to mitigate the negative impact of salt stress on plants and reclaim salt-affected lands. In the current study, we used silicon (Si) as a tool for salinity alleviation in soybean and investigated the influence of exogenous Si application on the regulation of reactive oxygen and reactive nitrogen species and other salt stress-related parameters of the treated plants. Our results revealed that the canopy temperature was much higher in sole NaCl-treated plants but declined in Si + NaCl-treated plants. Furthermore, the chlorophyll contents decreased with sole NaCl treatment, whereas Si + NaCl-treated plants showed improved chlorophyll contents. In addition, Si application normalized the photosynthetic responses, such as transpiration rate (E) and net photosynthesis rate (PN ) in salt-treated plants, and reduced the activity of ascorbate peroxidase and glutathione under salt stress. The expression levels of antioxidant-related genes GmCAT1, GmCAT2, and GmAPX1 started to decline at 12 h after addition of Si to NaCl-treated plants. Similarly, the S-nitrosothiol and nitric oxide (NO)-related genes were upregulated in the salt stress condition but reduced after Si supplementation. Si application downregulated genes associated with reactive oxygen species and reactive nitrogen species and reduced enzymatic and non-enzymatic antioxidants of the treated plants. Results of the current study conclude that Si mitigated the adverse effects of NaCl-induced stress by modulating the crosstalk between antioxidants and NO scavengers. It is suggested that Si may be used in agricultural systems for alleviating salt stress.

A test of taxonomic and biogeographic predictivity: resistance to soft rot in wild relatives of cultivated potato.

The concept that traits should be associated with related organisms and that nearby populations of the same species are likely to be more similar to each other than to populations spread far apart has long been accepted. Consequently, taxonomic relationships and biogeographical data are commonly believed to have the power to predict the distribution of disease resistance genes among plant species. In this study, we test claims of such predictivity in a group of widely distributed wild potato species. There was no clear association between resistance to soft rot and taxonomic relationships. However, we have found some associations between resistance to soft rot and environmental data such as annual precipitation and annual mean temperature. In addition, we have noted that high levels of resistance are mostly found in species with high levels of phenotypic plasticity. The three most resistant species were Solanum paucijugum, S. brevicaule, and S. commersonii.