In vitro acclimatization of Curcuma longa under controlled iso-osmotic conditions

In vitro acclimatization has been validated as the successful key to harden the plantlets before transplanting to ex vitro conditions. In the present study, we investigated the potential of different sugar types (glucose, fructose, galactose, sucrose) in regulating morphological, physiological and biochemical strategies, survival percentage and growth performance, and rhizome traits of turmeric under iso-osmotic potential. Leaf greenness (SPAD value) in acclimatized plantlets (4% glucose; −1.355 MPa osmotic potential) of ‘ST018’ was retained and greater than in ‘PB009’ by 1.69-fold, leading to maintain high F_v/F_m (maximum quantum yield of PSII), Φ_PSII (photon yield of PSII) and P_n (net photosynthetic rate) levels, and retained shoot height, leaf length, leaf width, shoot fresh weight and shoot dry weight after one month upon transplanting to ex vitro conditions. In addition, P_n, C_i (intracellular CO₂), g_s (stomatal conductance) and E (transpiration rate) in acclimatized plantlets (6% sucrose; −1.355 MPa osmotic potential) of ‘PB009’ were stabilized as physiological adapted strategies, regulating the shoot and root growth and fresh and dry weights of mini-rhizome. Interestingly, the accumulation of total curcuminoids in mini-rhizome derived from 6% sucrose acclimatized plantlets of ‘ST018’ was greater than in ‘PB009’ by 3.76-fold. The study concludes that in vitro acclimation of turmeric ‘PB009’ and ‘ST018’ using 6% sucrose and 4% glucose, respectively, promoted percent survival, physiological adaptations, and overall growth performances under greenhouse conditions.     

Salt tolerant screening in eucalypt genotypes (Eucalyptus spp.) using photosynthetic abilities, proline accumulation, and growth characteristics as effective indices

Eucalypts are highly regarded plantation trees due to their fast growing nature, high water consumption, tolerance to abiotic stresses, and ease of conversion to pulp and paper. We screened five genotypes of Eucalyptus camaldulensis (T5, BD4, 1-7-1, H1, and SH4) and three genotypes of the E. camaldulensis × Eucalyptus urophylla hybrid (H4, 58H2, and 27A2) for salt tolerance. Fresh weight and leaf area in hybrid genotypes (H4, 58H2, and 27A2) were greater than those in the E. camaldulensis population after plantlets were subjected to 200 mM NaCl for 14 d. The chlorophyll a content in hybrid genotypes decreased by 19.71–37.11% compared to 51.45–66.00% decline in E. camaldulensis. Similarly, total chlorophyll content was retained at a high level in the hybrid population, leading to stabilization of the net photosynthetic rate. The amount of proline, an osmolyte, was significantly increased in all Eucalyptus genotypes when exposed to 200 mM NaCl. Multivariate analyses of proline accumulation, photosynthetic pigment degradation, diminishing chlorophyll fluorescence, P _n reduction, and growth inhibition in salt-stressed plantlets of Eucalyptus genotypes were performed to classify salt-tolerant- and salt-sensitive groupings. The hybrid eucalypt genotypes H4, 58H2, and 27A2 were identified as salt tolerant while the selection genotypes of E. camaldulensis, T5, BD4, 1-7-1, H1, and SH4, were classified as salt susceptible.     

Exogenous NaCl salt elicitor improves centelloside content and physio-morphological adaptations in indian pennywort (Centella asiatica)

Journal of Plant Biochemistry and Biotechnology - Salt elicitation in therapeutic plants is one of the most popular techniques to enrich targeted secondary metabolites at cellular levels....