Growth and Nutritional Quality of Lemnaceae Viewed Comparatively in an Ecological and Evolutionary Context

This review focuses on recently characterized traits of the aquatic floating plant Lemna with an emphasis on its capacity to combine rapid growth with the accumulation of high levels of the essential human micronutrient zeaxanthin due to an unusual pigment composition not seen in other fast-growing plants. In addition, Lemna’s response to elevated CO2 was evaluated in the context of the source–sink balance between plant sugar production and consumption. These and other traits of Lemnaceae are compared with those of other floating aquatic plants as well as terrestrial plants adapted to different environments. It was concluded that the unique features of aquatic plants reflect adaptations to the freshwater environment, including rapid growth, high productivity, and exceptionally strong accumulation of high-quality vegetative storage protein and human antioxidant micronutrients. It was further concluded that the insensitivity of growth rate to environmental conditions and plant source–sink imbalance may allow duckweeds to take advantage of elevated atmospheric CO2 levels via particularly strong stimulation of biomass production and only minor declines in the growth of new tissue. It is proposed that declines in nutritional quality under elevated CO2 (due to regulatory adjustments in photosynthetic metabolism) may be mitigated by plant–microbe interaction, for which duckweeds have a high propensity.

Protein Biomarkers from Physiological Disorder Syndrome in Leave, Peel and Seed of Longan on Fruit Growth Using One-Dimension Electrophoresis Technique Followed by Protein Identification with LC-MS/MS

Proteomic investigation of leaves, peels and seeds on longan (Dimocarpus longan Lour. cv. Daw) at Maejo University’s farm in Chiang Mai province, Thailand. There were comparisons between normal and physiological disorder syndromes in longan on fruit growth (5, 10, 15, 20, 25 and 30 weeks fruition, respectively) by one dimensional electrophoresis (1-D gel) technique at a concentration of 12.5% gel in reducing condition with Coomassie brilliant blue R-250 staining coupling on liquid chromatography tandem mass spectrometry (LC-MS/MS). The research showed that vegetative storage protein (25.2 KDa), a storage protein in plants, was expressed in leaves, peels and seeds on before and after physiological disorder syndrome occurring. A protein involved on photosynthesis, the ribulose-1,5-bisphosphate carboxylase/oxygenase (48.3 KDa), was represented only on leaves at 30 weeks after fruition but not in peels and seeds of longan. Two proteins, the BnaC01g20210 (35.8 KDa) and predicted protein (40.11 KDa), which could not be identified the type and function of the metabolism, were decreased in diseased longan. These proteins may be important protein in part of the recovery process of abnormal longan. Therefore, advanced technique will be used for further proteomic studies.

Autumn dormancy regulates the expression of cas18, vsp and corF genes during cold acclimation of lucerne (Medicago sativa L.)

As a global forage legume, lucerne (alfalfa, Medicago sativa L.) is valuable for studying the evolutionary and ecological mechanisms of plant adaptation to freezing, owing to the characteristic of contrasting winter hardiness induced by autumn dormancy. Autumn-dormant lucerne plants often exhibit greater cold tolerance than non-dormant plants under natural field conditions. The study examined the autumn shoot growth of four diverse lucerne cultivars, and the influence of two sampling dates in late autumn, three sampling positions and four autumn-dormancy categories on cas18, vsp and corF gene transcripts during the first year of lucerne establishment. Results showed that in field-grown lucerne, non-dormant and highly non-dormant cultivars had greater shoot growth than a dormant cultivar in autumn. The level of transcripts of cas18 (which encodes a dehydrin-like protein) was highest in dormant cultivars and lowest in semi-dormant cultivars in both November and December; in particular, the cas18 transcripts in the crown remained highest in both November and December. The level of transcripts of vsp (which encodes vegetative storage protein) in all dormant cultivar tissues was highest in both November and December. In semi-dormant cultivars, the expression of vsp in the taproot increased compared with the lateral root and crown in November. The corF transcript in the dormant cultivar was markedly higher than in the semi-dormant cultivar and almost zero in the non-dormant and highly non-dormant cultivars. These results indicate that the significant impact of autumn dormancy and plant position on gene expression of cas18, vsp and corF occurring during autumn hardening, and continuing low temperatures, are likely to have significant consequences on lucerne productivity and its long-term persistence.