Anticipating warming related to climate change, commercial mango plantations in China have been shifting from lower to higher elevations. Such a practice may expose mangoes to climatic conditions that could affect photosynthesis. Photosynthesis research on mango has previously examined mature plantations but exploring adequate functions before the time of fruit production is necessary for later crop success. Therefore, we established two main commercial mango cultivars, Tainong No. 1 and Jinhuang, at 450 m and 1,050 m and examined their photosynthetic performance. Our results showed that photosynthetic capacity parameters, including maximum photosynthetic rate, apparent quantum yield, maximum carboxylation rate, and photosynthetic electron transport rate, were significantly different between cultivars due to elevation and positively correlated with leaf nitrogen per area. Moreover, the seasonal gas exchange of the two cultivars showed variations due to elevation, particularly during the warmer seasons. Therefore, elevation affects the photosynthetic performance of these mango cultivars.
The use of Jatropha curcas oil as a source of biofuel has been well-explored. However, the physiological and growth studies of J. curcas have received considerably lesser attention. In this study, leaf gas exchange measurements and leaf nitrogen content were determined for four varieties of J. curcas, grown in the field or in pots. Based on stable carbon isotope analysis (δ13C) and
gas-exchange studies, J. curcas is a C3 sun plant and the range of leaf photosynthetic rates (or CO2 assimilation rates, PNmax) were typically between 7 and 25 μmol(CO2) m-2 s-1 and light saturation generally occurred beyond 800 μmol(quanta) m-2 s-1. Higher rates of leaf photosynthesis were generally obtained with the mature leaves. In addition, increased foliar PNmax were recorded in potted J. curcas variety Indiana with increasing nitrogen (N) nutrition levels. These plants also showed greater growth, increased leaf N content, higher maximum CO2 assimilation capacity (PNhighCO2) and chlorophyll (Chl) content, indicating the potential of optimizing the growth of Jatropha by varying fertilizer nutrient levels. A rapid assessment for leaf N using a nondestructive and portable Chl meter had been established for J. curcas. This approach will allow repeated sampling of the same plant over time and thus enable the monitoring of the appropriate levels of soil fertility to achieve good Jatropha plantation productivity. High N nutrition improved the overall plant oil yield by increasing the total number of fruits/seeds produced per plant, while not affecting the intrinsic seed oil content. and J. W. H. Yong ... [et al.].
Leaf tissue of azalea cultivars was treated with fluoride by floating leaf discs on Solutions or by allowing KF to enter intact leaves via stem segments and petioles. In each čase, the photosynthetic rate was more strongly influenced by KF than the respiration rate or content of chlorophyll were.
The present study was conducted to determine the effect of exogenous application of brassinolide (BR) on Leymus chinensis grown under shade, i.e., control (100% natural light), mild shade (70% natural light), and moderate shade (50% natural light). Shade substantially enhanced the plant growth, synthesis of photosynthetic pigments, photosynthetic efficiency, and chlorophyll (Chl) fluorescence attributes of L. chinensis as compared with control. The order of increase was mild shade > moderate shade > natural light except Chl content, where the order of increase was moderate shade > mild shade > natural light. Likewise, application of BR resulted in further exacerbation of plant height, plant fresh and dry mass, but less in case of Chl and carotenoids contents, gas-exchange characteristics, and Chl fluorescence attributes. The results conclude that shade significantly enhanced plant growth through alterations in physiological attributes of L. chinensis, while, application of BR may not further improve the plant growth under shade., A. J. Yang, S. A. Anjum, L. Wang, J. X. Song, X. F. Zong, J. Lv, A. Zohaib, I. Ali, R. Yan, Y. Zhang, Y. F. Dong, S. G. Wang., and Obsahuje bibliografii
On the first day after foliar application, chitosan pentamer (CH5) and chitin pentamer (CHIT5) decreased net photosynthetic rate (PN) of soybean and maize, however, on subsequent days there was an increase in PN in some treatments. CH5 caused an increase in maize PN on day 3 at 10-5 and 10-7 M; the increases were 18 and 10 % over the control plants. This increase was correlated with increases in stomatal conductance (gs) and transpiration rate (E), while the intercellular CO2 concentration (Ci) was not different from the control plants. PN of soybean plants did not differ from the control plants except for treatment CH5 (10-7 M) which caused an 8 % increase on day 2, along with increased gs, E, and Ci. On days 5 and 6 the CHIT5 treatment caused a 6-8 % increase in PN of maize, which was accompanied by increases in gs, E, and Ci. However, there was no such increase for soybean plants treated with CHIT5. In general, foliar application of high molecular mass chitin (CHH) resulted in decreased PN, particularly for 0.010 % treated plants, both in maize and soybean. Foliar applications of chitosan and chitin oligomers did not affect (p > 0.05) maize or soybean height, root length, leaf area, shoot or root or total dry mass. and W. M. Khan, B. Prithiviraj, D. L. Smith.
The effect on traits of photosynthesis and water relations of assimilate demand was studied in olive tree that has strong alternate bearing. The diurnal and seasonal leaf gas exchanges, area dry mass, and saccharide and chlorophyll (Chl) contents were measured by comparing shoots with fruit of "on-trees" (heavy fruit load) with shoots without fruit on both "on-trees" and "off-trees" (light fruit load). In spite of large seasonal and diurnal differences, leaf net photosynthetic rate (PN), stomatal conductance (gs), sub-stomatal CO2 concentration (C1), transpiration rate (E), and respiration rate (RD) were not significantly influenced by fruit load or by the presence or absence of fruit on the shoot. An only exception was at the beginning of July when the one-year-old leaves on shoots with fruit had slightly higher PN and E than leaves on shoots without fruit. Water content, Chl and saccharide contents, and area dry mass of the leaf were not substantially influenced by the presence/absence of fruit on the shoot or fruit load. Hence the sink demand, associated with fruit growth, did not improve leaf photosynthetic efficiency in olive.
Agronomic traits, photosynthetic pigments, gas exchange, and chlorophyll (Chl) fluorescence parameters of red stem buckwheat (Fagopyrum dibotrys Hara) mutants induced by γ-radiation were compared with green control at seedling stage. Plant height, number of first-class branches, and rhizome biomass were inhibited significantly (p<0.01). Chl a, Chl b, and Chl a+b contents decreased with elevated dose of γ-rays, while increasing carotenoid content indicated that buckwheat was capable of adjusting to the radiation damage. Decrease in net photosynthetic rate was the result of both stomatal and non-stomatal limitations. Fluorescence parameters, such as F0, Fm, Fv/Fm, Fv/F0, ΦPS2, electron transport rate, and photochemical quenching declined significantly (p<0.01) as compared with control due to photoinhibition, while non-photochemical quenching increased to enhance thermal dissipation. Lower parameters implied that leaf tissue was damaged significantly by high dose of γ-radiation and therefore leaf senescence was accelerated. and C. F. Jia, A. L. Li.
The present study was undertaken to investigate the effect of Glomus mosseae on chlorophyll (Chl) content, Chl fluorescence parameters and chloroplast ultrastructure of beach plum seedlings under 2% NaCl stress. The results showed that compared to control, both Chl a and Chl b contents of NaCl + G. mosseae treatment were significantly lower during the salt stress, while Chl a/b ratio increased significantly. The increase of minimal fluorescence of darkadapted state (F0), and the decrease of maximal fluorescence of dark-adapted state (Fm) and variable fluorescence (Fv) values were inhibited. The maximum quantum yield of PSII photochemistry (Fv/Fm), the maximum energy transformation potential of PSII photochemistry (Fv/F0) and the effective quantum yield of PSII photochemistry (ΦPSII) increased significantly, especially the latter two variables. The values of the photochemical quenching coefficient (qP) and the nonphotochemical quenching (NPQ) were similar between G. mosseae inoculation and noninoculation. It could be concluded that G. mosseae inoculation could protect the photosystem II (PSII) of beach plum, enhance the efficiency of primary light energy conversion and improve the primitive response of photosynthesis under salinity stress. Meanwhile, G. mosseae inoculation was beneficial to maintain the integrity of thylakoid membrane and to protect the structure and function of chloroplast, which suggested that G. mosseae can alleviate the damage of NaCl stress to chloroplast., X. M. Zai ... [et al.]., and Obsahuje bibliografii
Cyanobacterial NDH-1 interacts with PSI to form NDH-1-PSI supercomplex. CpcG2, a linker protein for the PSI-specific peripheral antenna CpcG2-phycobilisome, is essential for stabilization of the supercomplex. Green light (GL) increased the expression of CpcG2 but had little effect, if any, on the expression of NDH-1 and PSI, when compared to the abundance of these components under red light (RL). The increased expression of CpcG2 intensified the band of NDH-1-PSI supercomplex after blue-native gel electrophoresis of the thylakoid membrane, possibly by stabilizing the supercomplex. The activity of NDH-1-dependent cyclic electron transport around PSI increased when cells grown under RL were transferred to a low intensity GL but was suppressed when cells were grown under high intensities of GL. The functionality of PSI showed the same trend. We thus conclude that GL increases the expression of CpcG2, thereby increasing the abundance of the NDH-1-PSI supercomplex and its activity at low GL but not at higher GL., F. Gao, T. Ogawa, W. Ma., and Obsahuje bibliografické odkazy
In two winter wheat (Triticum aestivum L.) cultivars differing in their response to high temperature, JD8 (tolerant) and J411 (sensitive) we studied the effect of heat stress on the activities of phosphoenolpyruvate carboxylase (PEPC) and ribulose-1,5-bisphosphate carboxylase (RuBPC) in green organs during grain-filling. There were significantly higher PEPC activities and lower RuBPC activities in each of the non-leaf organs (awn, glume, lemma, peduncle, and sheath) than in the flag leaf blade. Under heat stress for 12 d, the activity of RuBPC quickly declined and the activity of PEPC first increased and later declined in all organs, resulting in a great increase of the PEPC/RuBPC ratios in the organs, particularly in non-leaf organs which had a higher PEPC/RuBPC than the flag leaf blade in all times. The PEPC activity and PEPC/RuBPC ratio in every organ of JD8 were higher than those in the same organ of J411. Thus the differences in PEPC activities and PEPC/RuBPC may be associated with the differences in photosynthetic heat tolerance among the organs of the same plant or between the two cultivars. and X. L. Xu, Y.-H. Zhang, Z.-M. Wang.