scholarly journals Influence of Plant Growth at High CO2 Concentrations on Leaf Content of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase and Intracellular Distribution of Soluble Carbohydrates in Tobacco, Snapdragon, and Parsley

1997 ◽  
Vol 115 (1) ◽  
pp. 241-248 ◽  
Author(s):  
Bd. Moore ◽  
D. E. Palmquist ◽  
J. R. Seemann
2019 ◽  
Vol 20 (2) ◽  
pp. 353 ◽  
Author(s):  
Manzer Siddiqui ◽  
Saud Alamri ◽  
Mutahhar Al-Khaishany ◽  
M. Khan ◽  
Abdullah Al-Amri ◽  
...  

Melatonin, a natural agent, has multiple functions in animals as well as in plants. However, its possible roles in plants under abiotic stress are not clear. Nowadays, soil salinity is a major threat to global agriculture because a high soil salt content causes multiple stresses (hyperosmotic, ionic, and oxidative). Therefore, the aim of the present study was to explore: (1) the involvement of melatonin in biosynthesis of photosynthetic pigments and in regulation of photosynthetic enzymes, such as carbonic anhydrase (CA) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco); (2) the role of melatonin in osmoregulation by proline and carbohydrate metabolism; and (3) the function of melatonin in the antioxidant defense system under salinity. Outcomes of the study reveal that under non-saline conditions, application of melatonin (20 and 50 µM) improved plant growth, viz. shoot length, root length, shoot fresh weight (FW), root FW, shoot dry weight (DW), root DW and leaf area and physio-biochemical parameters [chlorophyll (Chl) a and b, proline (Pro) and total soluble carbohydrates (TSC) content, and increased the activity of CA and Rubisco]. However, tomato seedlings treated with NaCl exhibited enhanced Chl degradation, electrolyte leakage (EL), malondialdehyde (MDA) and reactive oxygen species (ROS; superoxide and hydrogen peroxide). ROS were detected in leaf and root. Interestingly, application of melatonin improved plant growth and reduced EL, MDA and ROS levels through upregulation of photosynthesis enzymes (CA, Rubisco), antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase and ascorbate reductase) and levels of non-enzymatic antioxidants [ascorbate (ASC) and reduced glutathione (GSH)], as well as by affecting the ASC—GSH cycle. Additionally, exogenous melatonin also improved osmoregulation by increasing the content of TSC, Pro and Δ1-pyrroline-5-carboxylate synthetase activity. These results suggest that melatonin has beneficial effects on tomato seedlings growth under both stress and non-stress conditions. Melatonin’s role in tolerance to salt stress may be associated with the regulation of enzymes involved in photosynthesis, the antioxidant system, metabolism of proline and carbohydrate, and the ASC—GSH cycle. Also, melatonin could be responsible for maintaining the high ratios of GSH/GSSG and ASC/DHA.


2020 ◽  
Vol 40 (12) ◽  
pp. 1726-1743
Author(s):  
Agnieszka Szuba ◽  
Łukasz Marczak ◽  
Izabela Ratajczak

Abstract It is believed that resource exchange, which is responsible for intensified growth of ectomycorrhizal plants, occurs in the fungus–plant interface. However, increasing evidence indicates that such intensified plant growth, especially root growth promotion, may be independent of root colonization. Nevertheless, the molecular adjustments in low-colonized plants remain poorly understood. Here, we analysed the metabolome of Populus × canescens microcuttings characterized by significantly increased growth triggered by inoculation with Paxillus involutus, which successfully colonized only 2.1 ± 0.3% of root tips. High-throughput metabolomic analyses of leaves, stems and roots of Populus × canescens microcuttings supplemented with leaf proteome data were performed to determine ectomycorrhiza-triggered changes in N-, P- and C-compounds. The molecular adjustments were relatively low in low-colonized (M) plants. Nevertheless, the levels of foliar phenolic compounds were significantly increased in M plants. Increases of total soluble carbohydrates, starch as well as P concentrations were also observed in M leaves along with the increased abundance of the majority of glycerophosphocholines detected in M roots. However, compared with the leaves of the non-inoculated controls, M leaves presented lower concentrations of both N and most photosynthesis-related proteins and all individual mono- and disaccharides. In M stems, only a few compounds with different abundances were detected, including a decrease in carbohydrates, which was also detected in M roots. Thus, these results suggest that the growth improvement of low-colonized poplar trees is independent of an increased photosynthesis rate, massively increased resource (C:N) exchange and delivery of most nutrients to leaves. The mechanism responsible for poplar growth promotion remains unknown but may be related to increased P uptake, subtle leaf pigment changes, the abundance of certain photosynthetic proteins, slight increases in stem and root amino acid levels and the increase in flavonoids (increasing the antioxidant capacity in poplar), all of which improve the fitness of low-colonized poplars.


2020 ◽  
Vol 8 (1) ◽  
pp. 342
Author(s):  
Monyck Jeane dos Santos Lopes ◽  
Moacyr Bernardino Dias-Filho ◽  
Thomaz Henrique dos Reis Castro ◽  
Edilson Ferreira da Silva ◽  
Marcela Cristiane Ferreira Rêgo ◽  
...  

The aim of this study was to evaluate the effects of plant growth-promoting rhizobacteria effects on anatomical characteristics and nutritional value of Brachiaria (Syn. Urochloa) brizantha cv. BRS Piatã. The experimental design applied was completely randomized design  with three treatments: (1) non-inoculated unfertilized-control plants (C-), (2) non-inoculated fertilized-control plants (C+) and (3) B. brizantha inoculated with Pseudomonas fluorescens (BRM-32111) and Burkholderia pyrrocinia (BRM-32113). The following parameters were evaluated at 35 days after seedling emergence: biomass production, plant height, net photosynthesis (A), water-use efficiency (WUE), chlorophyll (SPAD), anatomical and nutritional. The rhizobacteria modified the anatomy of the leaf, culm and roots of B. brizantha. They also increased the chlorophyll content, A, WUE, total soluble carbohydrates, starch and crude protein contents, N, P, Mg and Fe concentrations, plant height, root area and biomass production. Therefore, we conclude that co-inoculation with P. fluorescens (BRM-32111) and B. pyrrocinia (BRM-32113) modified the anatomy and biochemistry of B. brizantha, promoting growth and nutrient accumulation. Therefore, these findings set up the basis for additional exploratory studies, using these rhizobacteria as biotechnological innovation with potential of use as biofertilizer in B. brizantha, aiming higher productivity and nutritive value in a more eco-friendly and sustainable pasture production system.


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