In comparison to deciduous species, evergreen plants have lower leaf nutrient contents and higher leaf life span, important mechanisms for nutrient economy, allowing the colonization of low fertility soils. Strategies to conserve nitrogen in two semideciduous tropical forest tree species, with different leaf life spans were analyzed. The hypothesis was the fact that the two species would presen...

Ascorbic acid (Asc) is a major antioxidant in plants that detoxifies reactive oxygen species (ROS) and maintains photosynthetic function. Expression of dehydroascorbate reductase (DHAR), responsible for regenerating Asc from an oxidized state, regulates the cellular Asc redox state, which in turn affects cell responsiveness and tolerance to environmental ROS. Because of its role in Asc recyclin...

It has been known since Herlitzka's work in 1912 that it is possible to prepare colloidal solutions of chlorophyll by grinding plant tissue. Lubimenko (1927) found that some leaves (Funkia and Aspidistra genuses) gave on extraction with water clear stable green solutions which contained all the chlorophyll of the original leaf in combination with a protein. Other leaves gave extracts which cont...

We have extended a conventional photosynthesis model to simulate field and laboratory measurements of chlorophyll fluorescence at the leaf scale. The fluorescence paramaterization is based on a close nonlinear relationship between the relative light saturation of photosynthesis and nonradiative energy dissipation in plants of different species. This relationship diverged only among examined dat...

The ambient mass spectrometry technique, desorption electrospray ionization mass spectrometry (DESI-MS), is applied for the rapid identification and spatially resolved relative quantification of chlorophyll degradation products in complex senescent plant tissue matrixes. Polyfunctionalized nonfluorescent chlorophyll catabolites (NCCs), the "final" products of the chlorophyll degradation pathway...

tomato plays an important role in providing vitamins and minerals in human nutrition, it has a great potential in exports. as well as it is an important vegetable due to its variety of vitamins, carotene, useful acids, sugar and minerals play an important role in human health. regarding the fact that tomato is one of the most significant products and its consumption is rising up day after day, ...

The use of fluorescence induction measurements in leaves infiltrated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea has been evaluated as a routine method for estimation of the concentration of the reaction centers of photosystem II relative to total chlorophyll in a wide variety of plant species. The procedure is based on a simple theory that takes into account the attenuation of light in passin...

This study was conducted to determine the effects of different irrigation water treatments and silicon doses on leaf SPAD meter readings, chlorophyll content carotenoid contents tomato plants. Tybiff Aq seedling were grown in 3-liter pots filled with 1100 g 1:1 peat-perlite mixture for 70 days. Four type waters prepared use sea tap water. Irrigation included I) Full water, II) ½ + III) ¼ ¾ IV) ...

Grape phylloxera is a root-feeding pest of grapevines. In Australia, phylloxera infested vineyards are subjected to quarantine restrictions and early detection remains vital for the timely implementation of post-outbreak quarantine protocols. Current detection methods rely on time-consuming ground surveying which involves detailed examination of grapevine (Vitis vinifera L.) root systems. Leaf ...

The net photosynthetic rate, chlorophyll content, chlorophyll fluorescence and 820 nm transmission were investigated to explore the behavior of the photosynthetic apparatus, including light absorption, energy transformation and the photoactivities of photosystem II (PSII) and photosystem I (PSI) during senescence in the stay-green inbred line of maize (Zea mays) Q319 and the quick-leaf-senescen...