Plant physiology

About: Plant physiology is a research topic. Over the lifetime, 1537 publications have been published within this topic receiving 72038 citations.

Influence of Exogenous Hydrogen Peroxide on Plant Physiology, Leaf Anatomy and Rubisco Gene Expression of the Ficus deltoidea Jack var. Deltoidea

Abstract: This study was carried out to investigate the regulatory effects of hydrogen peroxide (H2O2) on the growth, photosynthesis, biochemical properties, leaf anatomy and Rubisco gene expression in Ficus deltoidea var. deltoidea, a slow-growing medicinal herb. Results showed that 20-mM H2O2 treatment increased plant height, net photosynthetic rate, stomatal conductance and chlorophyll content of the plants by 10%, 20%, 127% and 57%, respectively, than a control plant. In addition, 20 mM H2O2 treatment significantly increased the carotene, total phenolic, total flavonoid and total sugar content than the control plant. The applications of H2O2 did not produce any negative effects on the leaf area, chlorophyll fluorescence, quantum yield or antioxidant activity of F. deltoidea plants. In regard to leaf anatomy, it was observed that the applications of H2O2 at 15 mM significantly improved cellular structure, leaf veins and promoted cell proliferation. Treated leaves developed a palisade layer, thickened leaf surface, the widest stomatal openings and a well-developed vascular bundle when compared to the control plant. Employing reverse transcription polymerase chain reaction (RT-PCR), the study showed that the Rubisco gene was expressed at a higher level in 15 mM H2O2 treatments than in 20 mM H2O2 treatments. The results indicate that H2O2 increased the Rubisco expression ratio up to 16-fold when compared to the untreated plants. It was conclusive that spraying 15 mM and 20 mM H2O2 twice a week enhanced growth, photosynthesis, the stomatal aperture, improved leaf anatomy and helped to regulate the expression of the Rubisco gene.

Air ion effect on respiration and photosynthesis of barley and Antirrhinum majus

Abstract: Stem height increases of 13% and 15% for barley and snapdragon respectively were observed for plants maintained in an atmosphere of high concentrations of negative air ions compared to control plants. Dry weights of the exposed plant species to negative ions increased by approximately 18% compared to untreated plants. The effects of positive air ions were insignificant. The rates of photosynthesis and respiration measurements on continuously exposed plants to negative air ions conformed to these observations.

Improve Plant Photosynthesis by a New Slow-Release Carbon Dioxide Gas Fertilizer.

Abstract: In the natural state, the concentration of carbon dioxide in the atmosphere is about 300 μmol mol-1. Plants need a suitable balance of CO2 to achieve optimal growth. The optimum CO2 content corresponding to a high photosynthesis rate is between 0.1 and 1.0% by volume. However, air has only a CO2 content of 0.03% by volume, so plants cannot use all of their growth potential. The use of fertilizer to assist in the supply of CO2 increases the rate of photosynthesis. In this work, a slow-release CO2 gas fertilizer inspired by polyphenol chemistry was prepared to provide sustainable CO2 that could improve plant photosynthetic capacity and get a higher crop yield. The core-shell structure was designed to confer gas fertilizers slow-release property. Micron-sized calcium carbonate particles with uniform particle size and regularity morphology, as carbon sources for plant photosynthesis, was a core, and tannic acid was coated on it as a shell via oxidative oligomerization and cross-linked by polyetherimide. The structure and morphology of fertilizers were characterized by scanning electron microscopy, X-ray energy dispersive spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. In vitro experiments, the prepared fertilizers were proved to have slow-release properties. And then through net photosynthesis rate, chlorophyll fluorescence parameters, chlorophyll content, leaf area, leaf mass per area, and dry matter to study the effects of slow-release CO2 gas fertilizers on plant physiology of Brassica chinensis. The results revealed that the slow-release CO2 gas fertilizers not only had good slow-release properties but also can well improve plant photosynthesis.

Plant Age Affects Wound-Induced Senescence in Lactuca Sativa L

Abstract: In the present study we investigated the performance of dark-stored wounded leaf discs and pieces (to some extent mimicking fresh-cut product) of Lactuca sativa L. in relation to the physiological maturity at harvest. We used two related genotypes, i.e. a green (cv. Troubadour) and a red butterhead (cv. Teodore) differing in their pigment levels. For both genotypes, senescence of the wounded (fresh-cut) tissue prepared from leaves of younger plants was significantly delayed compared to wounded tissue prepared from the more mature plants. Shelf-life (time to unacceptable quality) of fresh-cut was doubled when plants were harvested one week before the commercial harvesting date. To explain differences in shelf-life between fresh-cut products prepared from plants harvested at different age, a number of physiological and nutritional parameters were determined at harvest. The red lettuce contained about two times more chlorophyll, carotenoids, and polyphenolic antioxidants than the green lettuce, but the shelf-life of both genotypes was about similar. Increasing the amount of pigments and polyphenols through application of LED light (with high percentage blue) during cultivation did not affect the shelf life of the wounded leaf tissue. The content of chlorophyll, carotenoids, phenolic compounds, as well as total antioxidant capacity was not affected by age of the plants for either genotype. The content of ascorbic acid decreased with maturation in the green lettuce but it was not affected by maturity in the red lettuce. This shows that there are no obvious signs of leaf senescence with age and the differences in pigments and antioxidants show no relation to the fresh-cut shelf life and thus cannot explain the effect of plant age on senescence of the wounded tissue. The net photosynthesis rate and carbohydrate reserves in the red lettuce were about half of that in the green lettuce but the shelf-life of both genotypes was similar. The net photosynthesis rate was not influenced by plant maturity in the green lettuce, whereas it decreased with maturation in the red lettuce. A decrease in sucrose and starch, and therefore the total content of carbohydrates with aging was observed in both genotypes. This effect was more pronounced in the red than in the green lettuce. There was no apparent relationship between the absolute levels of the total carbohydrates and the shelf-life of the fresh-cut product showing that carbohydrate reserves in itself cannot explain the effect of plant age on senescence of the wounded tissue. The leaves from older plants apparently have a reduced capability to cope with the stress from wounding. No simple one to one relationship emerged between any of the measured nutritional parameters, their change during maturation and the eventual shelf-life of the fresh-cut produce.