Understanding the mechanisms of plant tolerance to osmotic and chemical stress is fundamental to maintaining high crop productivity. Soil drought often occurs in combination with physiological drought, which causes chemical stress due to high concentrations of ions. Hence, it is often assumed that the acclimatization of plants to salinity and drought follows the same mechanisms. Grass pea (Lathyrus sativus L.) is a legume plant with extraordinary tolerance to severe drought and moderate salinity. The aim of the presented study was to compare acclimatization strategies of grass pea seedlings to osmotic (PEG) and chemical (NaCl) stress on a physiological level. Concentrations of NaCl and PEG were adjusted to create an osmotic potential of a medium at the level of 0.0, −0.45 and −0.65 MPa. The seedlings on the media with PEG were much smaller than those growing in the presence of NaCl, but had a significantly higher content percentage of dry weight. Moreover, the stressors triggered different accumulation patterns of phenolic compounds, soluble and insoluble sugars, proline and β-N-oxalyl-L-α,β-diamino propionic acid, as well as peroxidase and catalase activity. Our results showed that drought stress induced a resistance mechanism consisting of growth rate limitation in favor of osmotic adjustment, while salinity stress induced primarily the mechanisms of efficient compartmentation of harmful ions in the roots and shoots. Furthermore, our results indicated that grass pea plants differed in their response to drought and salinity from the very beginning of stress occurrence.

In vitro cultures of Leucojum aestivum are considered as an alternative for the production of galanthamine, which is used for the symptomatic treatment of Alzheimer’s disease. We studied the effects of auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (picloram), 3,6-dichloro-o-anisic acid (dicamba) at concentrations of 25 and 50 µM on the induction of embryogenic callus and its capacity to induce somatic embryogenesis and alkaloid accumulation. The embryogenic response of the explants was from 30% for 25 µM of dicamba to 100% for picloram (for both 25 and 50 µM). 2,4-D (50 µM) stimulated greater callus proliferation and somatic embryo induction as compared to the other auxins. Polyethylene glycol (PEG) stimulated somatic embryo maturation. Callus grown on media containing 50 µM of auxins produced fewer phenolic compounds as compared with callus grown on media containing 25 µM of auxins. GC-MS analyses showed seven alkaloids in the in vivo bulbs and two to four in callus culture. Galanthamine was detected in callus cultivated with 2,4-D (25, 50 µM), picloram (25 µM), and dicamba (50 µM). Other alkaloids, trisphaeridine, tazettine, and 11-hydroxyvittatine were accumulated only in callus growing on medium with picloram (50 µM).

Plants growing under natural conditions are constantly exposed to ultraviolet (UV), primarily UV-A, radiation. Grass pea (Lathyrus sativus L.) is a legume species resistant to harsh growing conditions, such as drought, salinity or periodic flooding. Due to the advantageous composition of seeds, it is used for consumption in such regions as South Asia or East Africa where high intensity of UV radiation occurs. Absorption of this spectral range causes changes in the photosynthetic apparatus of plants, including damage to the photosystem II (PSII) reaction centres. The aim of the work was to examine whether the use of the combination UV-A: red light as a source of radiation would enable quick acclimatization of the photosynthetic apparatus of grass pea to the negative effect of UV-A radiation. 14-day-old plants were exposed to UV-A:red radiation for 48 h. The plants exposed to UV-A:red radiation showed enhanced effective efficiency of PSII and increased total electron carriers, which enabled more effective photosynthesis at higher values of radiation intensity in comparison with control plants, kept under white LED light. At the same time, there were no statistically significant differences in both the photosynthetic pigment contents and the level of lipid peroxidation. The obtained results indicate that the observed increase in the efficiency of CO 2 carboxylation after short-term UV-A:red radiation has resulted from the efficient linear electron transport due to maintaining the effective oxygen evolving complex (OEC) and increased total electron carriers.

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Vigor and selected physiological parameters (content of phenolic compounds, soluble sugars, chlorophyll a and b, and carotenoids) of eight naked and two husked oat cultivars harvested at 15% moisture content were determined. Oat seeds were threshed using two rotational speeds of the threshing drum: 1.6 ms −1 (LS) and 2.4 ms −1 (HS). They were then inoculated with a medium pathogenicity strain of Fusarium culmorum, strain IPO 348-01. In naked cultivars, the use of HS resulted in more severe mechanical damage; in consequence, seedling vigor decreased by 16%. In naked cultivars chlorophyll a and b and carotenoids content were significantly reduced-by more than 64%-when the HS was used. The inoculation caused over a 100% increase of carbohydrates in roots at LS but only a slight increase at HS. Phenolic compound content was twice as high in roots than in leaves after inoculation for both LS and HS. Area of microdamage and reduction of root fresh weight (f.wt.) are significantly correlated with biochemical parameters. Smaller microdamage area and root f.wt. reduction are connected with higher physiological parameters, which confirms lower seedling susceptibility to pathogen infection.