In order to evaluate the effects of methanol and drought stress on CHLOROPHYLL fluorescence parameters, CHLOROPHYLL and relative water CONTENT in sugar beet, a study was conducted in 2008 in Iran. Aqueous solutions 0 (control), 7, 14, 21, 28, 35% (v/v) methanol and each solution contained 0.2% glycine and second factor was drought stress (irrigation after 70% depletion of available water) and normal irrigation (irrigation after 40% depletion of available water). These solutions were sprayed over head 3 times in two week intervals on foliage parts of sugar beet. Results of this experiment indicated that there was not significant difference between levels of solutions on minimum CHLOROPHYLL fluorescence (f0), fluorescence variable (Fv) and maximum CHLOROPHYLL fluorescence (fm), but there was significant difference between levels of solutions on photochemical capacity of photosystem 2 (Fv/fm) at 5% probability level.

To evaluate the effects of methanol and drought stress on CHLOROPHYLL fluorescence parameters, CHLOROPHYLL and relative water CONTENT in sugar beet, a study was conducted in 2008 in Maahdasht (Karaj, Iran). Aqueous solutions of 0 (control), 7, 14, 21, 28, 35% (v/v) methanol with each solution containing 0.2% glycine and a second factor, namely drought stress (irrigation after 70% depletion of available water) and normal irrigation (irrigation after 40% depletion of available water) constituted the treatments. The solutions were sprayed overhead, 3 times in two week intervals on foliage parts of the crop sugar beet. Results indicated that there was no significant difference between levels of solution on minimum CHLOROPHYLL fluorescence (F0), fluorescence variavle (FV) and maximum CHLOROPHYLL fluorescence (FM), but there was a significant difference observed between levels of solutions on photochemical capacity of photosystem 2 (FV/FM) at a 5% probability level. Analysis of variance revealed that before a third foliar application, CHLOROPHYLL CONTENT did not show any significant difference, whereas there was a significant difference observed among levels of solutions on CHLOROPHYLL CONTENT after the third application at a 5% probability level.Also results indicated that drought stress significantly decreased photochemical capacity of photosystem 2 (FV/FM), fluorescence variavle (FV) and maximum CHLOROPHYLL fluorescence (FM) at 5% probability level. As for minimum CHLOROPHYLL fluorescence (F0) no significant difference was observed between the two levels of irrigation. Also drought stress significantly increased CHLOROPHYLL CONTENT at 5% probability level. Both factors (levels of solution and different irrigation levels) affected relative water CONTENT (RWC) at 1% probability level. The highest correlation was observed between white sugar yield and photochemical capacity of photosystem 2 (FV/FM). In this study interactive effect was not found to be significant.

In order to investigate the effects of methanol application on some physiological properties of soybean under low water stress, a factorial experiment was conducted at Research Field of Faculty of Agriculture and Natural Resources, Islamic Azad University-Karaj Branch, Karaj, Iran, during 2008, based on a randomized complete block design with three replications. The first factor was consisted of different levels of methanol equal to 0 (control), 7, 14, 21, 28 and 35 volumetric percentage (v/v), which were used as foliar applications at three times during growth season of soybean, with 15 days intervals. The second factor was water stress conditions in two levels, based on depletion of 40 and 70% of available soil moisture. Some traits such as grain yield (GY), relative water CONTENT (RWC), CHLOROPHYLL fluorescence parameters, and CHLOROPHYLL CONTENT were measured, one day before and after the third methanol application. Results showed that CHLOROPHYLL CONTENT (Chl), GY, electrolytes leakage (EL) at second sampling, photochemical capacity of PSII (Fv/Fm), maximum and variable fluorescence (Fm and FV, respectively) were affected by water stress significantly (p<0.05). As drought severity was increased, mean values of Fv/Fm, Chl and RWC tend to decline, whereas minimum (initial) fluorescence (F0) and El were increased. Methanol foliar application influenced significantly (p<0.05) Chl, GY, Fv/Fm, Fm, Fv, and RWC. There was a positive, high correlation between GY with Fm, Fv/Fm, and also Chl and RWC in both samplings. It seems applying methanol on water stressed soybean plants can reduce harmful effects of drought and improve plant potential to cope with stress.

CHLOROPHYLL fluorescence could be used as an index for evaluation of stress tolerance in plants. A field experiment was conducted using 3 wheat varieties along with seven irrigation levels in a factorial arrangement of a randomized complete block design with four replications. CHLOROPHYLL fluorescence parameters were measured on plant flag leaves about 3 weeks after anthesis. Variations of maximum CHLOROPHYLL fluorescence (FM), fluorescence variable (FV), minimum CHLOROPHYLL fluorescence (F0),half time of increase from F0 to FM (T1/2) and the photochemical capacity of photo-system II (FV/FM), were evaluated. Relative water CONTENT and flag leaf CHLOROPHYLL CONTENT were measured. Results showed that different irrigation levels affect FV, FV/FM and T1/2 significantly(P £0.05).Both factors of cultivars, and different irrigation levels affected CHLOROPHYLL CONTENT, RWC and grain yield (GY) significantly (p£0.01). Mean FV/FM, FV, T1/2 and FM declined as soil water CONTENT was decreased, but F0 almost remained constant for all the treatments. High yielding varieties exhibited higher values for TI/2, FM, FV/FM, FV, CHLOROPHYLL CONTENT and RWC. The highest correlation coefficient was observed between grain yield and FV as well as FV/FM, while the lowest detected between grain yield and F0.The existence of similar patterns of variation in fluorescence parameters in all varieties indicates that high yielding varieties can overcome the effects of drought stress during grain filling period, this being confirmed by correlation between fluorescence parameters and RWC.

Citrus canker has worldwide distribution and is still a devastating disease caused by the bacteria Xanthomonas citri subsp. citri (Xcc). With the aim of evaluating C. aurantifolia response mechanism, plant leaves non-inoculated and inoculated with the bacteria were collected in 1, 4, and 7 days post-inoculation. Consequently, the CHLOROPHYLL pigment CONTENT and fluorescence were determined, and proteomics study was conducted. Results indicated that pathogen infection, despite the negative effect on CHLOROPHYLL pigment CONTENT, improved the physiological condition. The maximum efficiency of PSII photochemistry and PSII quantum Yield (YPSII) as well as photochemical quenching increase were observed in infected plants compared to the control, whilst nonphotochemical quantum decreased during infection. Judging by the results, the proteomic analysis revealed that these responses were mirrored by rapid changes in the host proteome that included the up-regulation of carbohydrate metabolism proteins and down-regulation of the ATP generating proteins during pathogen infection. The results indicated that the pathogen manipulates the host homeostasis by its effector proteins to exploit in its favor.

The effect of automobile pollution was determined on CHLOROPHYLL CONTENT of four different tree species viz. Azadirachta indica L., Conocarpus erectus L., Guiacum officinale L. and Eucalyptus sp. growing along the roads of the city. Significant changes in the level of CHLOROPHYLL “a”, CHLOROPHYLL “b” and total CHLOROPHYLL “a+b” were found in the leaves of four tree species (A. indica, C. erectus, G.officinale and Eucalyptus sp.) collected from polluted sites (Airport, Malir Halt, Quaidabad) as compared to control site (Karachi University Campus). Lowest concentration of CHLOROPHYLL “a”, CHLOROPHYLL “b” and CHLOROPHYLL “a+b” was recorded in the leaf samples of all tree species collected from Quaidabad site when compared with the leaf samples collected from control site. The highest levels of CHLOROPHYLL pigment were recorded in all tree species leave samples collected from Karachi University Campus. Similarly, better levels of CHLOROPHYLL “a”, CHLOROPHYLL “b” and total CHLOROPHYLL “a+b” was observed in all tree species growing at Airport site as compared to plants growing at Malir Halt and Quaidabad sites. This study clearly indicated that the vehicular activities induced air pollution problem and affected on the level of CHLOROPHYLL pigments in trees which were exposed to road side pollution.

In arid and semi-arid areas of the world, excessive mineral aerosol carried by air parcels is a common climatic incident with well-known environmental side effects. In this study, the role of sand-dust accumulation was investigated on various aspects of photosynthetic yield of Plantago lanceolata including CHLOROPHYLL (Chl) a, b, effective quantum yield of PSII photosystem (FPSII), maximal quantum yield of PSII photosystem (Fv/Fm), electron transport rate (ETR), and biomass. P. lanceolata was exposed to a gradient of dust concentrations (0.5 (T1), 1 (T2), and 1.5 g/m3 (T3)) in a dust chamber for a period of 60 days. Results of this experiment indicated that CHLOROPHYLL CONTENT of shoot is negatively correlated with the intensity of the dust exposure. Exposure of plant in T1, T2 and T3 treatments of dust caused a reduction in DF/Fm´ at 4%, 21%, and 26%, respectively. At the same time a reduction of 19%, 22%, and 46% in three treatments was observed for ETR. However, dust accumulation on the plant had not a significant reduction in Fv/Fm. CHLOROPHYLL CONTENT had a significant reduction in the CHLOROPHYLL b. Also, the amounts of reduction in shoot dry mass of T1, T2, and T3 treatments were 26%, 29%, and 32%, respectively, as compared with their respective control.

In order to understand some physiological mechanism of chilling and cold sensitivity in plants we investigate the effects of chilling and cold stress on CHLOROPHYLL and proline CONTENT, lipid peroxidation and variable CHLOROPHYLL fluorescence (Fv/Fm) of Arabidopsis (thaliana L.) The four weeks-old plants (WT, and four chilling sensitive mutants [chs 2-2], [chs 2-1], [chs 1-2] and [chs 1-1]) were subjected to two different low temperature treatments (control (23oC), chilling (13oC) and cold (4oC)), for one week. Fv/Fm and CHLOROPHYLL CONTENT changed significantly in all mutants except in WT by chilling stress (13oC), compared with control and 4oC treatments. Two out of four mutants, chs 1-1 and chs 1-2, had lowest CHLOROPHYLL CONTENT and Fv/Fm value among the tested genotypes. The proline CONTENT increased in all mutant genotypes, as well as in WT by chilling stress and 4oC, compared with control. MDA CONTENT of shoots changed dramatically in all mutant genotypes except in WT by chilling stress, compared with control and 4oC treatments. Our findings showed that two mutants, chs 1-1 and chs 1-2, have had highest chilling sensitivity among the tested genotypes and had the highest proline and MDA CONTENTs. It is possible that some damages in photosynthetic systems and/or in proline metabolism via mutation cause these plants more sensitive to chilling and cold stress.

An investigation of CHLOROPHYLL quick fluorsence variations was made in the Reaserch Field of Islamic Azad University- Karaj in 2007. The experimental design was a split plot one in form of a complete randomized block design with 4 replications.Drought stress was cosiderded in three levels of 40%, 60%, and 75%, on the basis of depletion of soil moisture as the main factor and the factor of microelements in three levels of 0, 3, 5 lit/ha. The evaluated traits were CHLOROPHYLL fluorsence parameters, RWC, CHLOROPHYLL CONTENT and cell memberane stability, as well as grain yield in two stages. Results, indicated that the stress effects on F0, chla, chlab and GY and also FV/FM, and chlb were significant at the first stage, while in the second stage they were significant on F0 (p<0.05), and while in other parameters they were non significant.The triat means of FV/FM, chlab, chlb, chla andcell memberan stability declined while F0 increased as drought stress levels increased (at the first stage), but at the second stage F0 increased although Fv decreased. At the first experimental time microelements' effects were significant on F0 (p<0.05) and EC (P<0.01) while at the second stage, they were significant on F0 (p<0.05). The means indicated that F0 increased in each stage, but cell membrane stability decreased although microelement levels increased. FV/FM, chlab, chla and EC had the highest while F0 the lowest correlation coefficient with grain yield. At the second stage the highest correlation coefficient was observed with FV/FM, FV, FM and the lowest with F0 with GY. Interaction effects were significant on EC (p<0.01) at the first and on F0 (p<0.05) at the second experimental time. Result showed that, masured parameters under drought stress can act as an index for determination of intensity of stress. Also FV/FM, FV, and even Fm are suitable for an investigation of intensity stress.