Photosynthetic pigments, betalains, proteins, sugars, and minerals during Salicornia brachiata senescence

Abstract

Senescence is the last developmental stage in plants during which recycling of nutrients takes place from senescing organs to newly formed organs such as young leaves and developing seeds. In the present work, senescence induced alterations in mineral ions, chlorophylls, carotenoids, betacyanin, betaxanthin, proteins, amino acids, sugars, starch, and polyphenols were monitored in shoots of an extreme halophyte Salicornia brachiata. A sharp decline in the content of chlorophylls, carotenoids, and proteins in the shoot was noticed at middle and late stages of senescence in comparison with early stage. However, the content of betacyanin, betaxanthin, total soluble sugars, reducing sugars, and starch increased significantly in senescing shoots. The total free amino acid content decreased gradually with the progress of senescence. The content of major minerals did not change significantly with the progress of senescence, whereas marked changes in content of minor minerals were observed. From this study, it was concluded that the sugars and starch accumulating in senescing shoots might be transported into developing seeds to serve as storage nutrients. The accumulation of betacyanin and betaxanthin in senescing shoots suggests that these pigments may act as scavengers of reactive oxygen species during senescence. This study provides comprehensive information on the variations in the utilization of mineral nutrients and organic metabolites with progressing senescence in the halophyte S. brachiata.

Mitigation of drought stress in rice crop with plant growth‐promoting abiotic stress‐tolerant rice phyllosphere bacteria

“…The supernatant was gently transferred into new tubes and 0.5 ml of sample was aliquoted and mixed with 80% acetone. Then, samples were checked for chlorophyll a, chlorophyll b, and carotenoid content by measuring the multiple absorbances at 663, 646, and 470 nm, [25] and calculated using the formula as follows: Approximately 5.0 g of leaf sample was homogenized in a pestle and mortar using 80% ethanol (v/v). The homogenate was incubated for 10 min at 70°C in the water bath and then centrifuged for 10 min at 10,000 rpm.…”

“…The supernatant was used to estimate TSSs by anthrone-sulfuric acid using 0.2% (w/v) anthrone in concentrated H 2 SO 4 as a reagent. Absorption was measured at 630 nm [25]. The standard curve was plotted with 0-1,000 µg of glucose.…”

“…The pellet was separated and dissolved in 1-M NaOH. The protein concentration was estimated using Lowry protein assay by measuring the absorption at 660 nm [25]. Bovine serum albumin was used as the standard.…”

Environmental and Management Considerations for Adopting the Halophyte Salicornia bigelovii Torr. as a Sustainable Seawater-Irrigated Crop.

“…The promising importance of Salicornia not only lies in the oil content of its seeds, or its potential use as fresh vegetables with high mineral content of their forage, but also because its response to watering, it is suitable candidate as a biofilter to recycle water and nutrients contained in effluents from marine aquaculture [19,20]. Salicornia has been studied by several researchers, studying its ecology, physiological responses to salinity changes, agricultural management, and utilization [18,20,21], also the phenology of related species with an emphasis on floristic aspects, the nutrient content [22,23], and other issues. On the coast of the Bay of La Paz BCS, México, it is possible to find Salicornia associated to halophytic vegetation and with diversified soil microbiota, both in winter and in spring, which decreases in summer and autumn due to a change in seasonal climate [24].…”

Research Progress of Betalain in Response to Adverse Stresses and Evolutionary Relationship Compared with Anthocyanin

“…The functional verification of stress tolerance-related genes is usually conducted by measuring the amount of proline or by quantitatively detecting the expression of genes involved in proline biosynthesis, such as P5CS1 and P5CS2 [36,37,38]. Surprisingly, it has been found that betalain not only exerts effects similar to those of anthocyanins and catechins and is an excellent scavenger of a great number of ROS types [6,39,40] but also works like proline to adjust the osmotic pressure of plants [34,39,41], anthocyanins do the same under similar conditions [42].…”