Response of photosynthesis to short-term drought stress in rice seedlings overexpressing C₄ phosphoenolpyruvate carboxylase from maize and millet

Z. S. Ding, X. F. Sun, S. H. Huang, B. Y. Zhou, M. Zhao

Photosynthetica 2015, 53(4):481-488 | DOI: 10.1007/s11099-015-0126-1

Abiotic stresses induce phosphoenolpyruvate carboxylase (PEPC) expression in C₃ plants which suggests PEPC function in plant adaptation to stresses. Here, we studied the response of photosynthesis to short-term drought stress in rice seedlings overexpressing C₄ PEPC from maize and millet. The transgenic lines exhibited 1.2-5.5 fold of PEPC activities than the wild type before the treatment, while 1.5-8.5 fold after five or ten days of water deficit. Net photosynthetic rate (P _N) declined less during the water stress and recovered more after rewatering in the transgenic lines. These changes were accompanied...

Diurnal and seasonal variations in photosynthetic characteristics of switchgrass in semiarid region on the Loess Plateau of China

Z. J. Gao, B. C. Xu, J. Wang, L. J. Huo, S. Li

Photosynthetica 2015, 53(4):489-498 | DOI: 10.1007/s11099-015-0108-3

In order to use rationally switchgrass (Panicum virgatum L.) introduced in a large scale in semiarid regions on the Loess Plateau of China, we investigated and compared soil water storage dynamics, diurnal and seasonal changes in leaf photosynthetic characteristics, and biomass production of switchgrass grown under three different row spacing (20, 40, and 60 cm). Results indicated that photosynthetic parameters showed a pronounced seasonality. Diurnal course of net photosynthetic rate (P _N) was bimodal, showing obvious midday depression, which was mainly due to stomatal limitation in May and June, by nonstomatal limitation...

Photosynthesis of a yellow-green mutant line in maize

X. M. Zhong, S. F. Sun, F. H. Li, J. Wang, Z. S. Shi

Photosynthetica 2015, 53(4):499-505 | DOI: 10.1007/s11099-015-0123-4

This study compared the relationship between chlorophyll (Chl) content, gas exchange, Chl fluorescence characteristics, and leaf color, using paired near-isogenic lines (NILs) of a medium-green leaf inbred line SN12 and a yellow-green leaf mutant SN62 to explore the photosynthesis of the yellow-green mutant. The SN62 was found in a female parent, Xianyu 335, which grew normally, although there were small yellow spots on the leaves at the seedling stage and yellow-green leaves appeared from the seedling to the maturation stage. The results indicated that Chl a (b), quantum efficiency of PSII, and maximal quantum yield of PSII photochemistry...

Effects of Cd on photosynthesis and growth of safflower (Carthamus tinctorius L.) genotypes

L. Moradi, P. Ehsanzadeh

Photosynthetica 2015, 53(4):506-518 | DOI: 10.1007/s11099-015-0150-1

Heavy metals such as cadmium (Cd) may affect different physiological functions in plants. We carried out a hydroponic experiment under greenhouse conditions in order to evaluate the effect of Cd on photosynthetic and physiological parameters of safflower. The responses of six safflower genotypes (Nebraska-10, 2811, Kouseh, S149, C111, and K12) to four concentrations of CdCl₂ (0, 1.5, 3, and 4.5 mg L^-1) were examined. Mean shoot and root dry masses of safflower plants were reduced by nearly 57% after the treatment by 4.5 mg(CdCl₂) L^-1. Contrary to the mean proline content, which increased by 121%, the mean...

Low contribution of photosynthesis and water-use efficiency to improvement of grain yield in Chinese wheat

X. Chen, M. D. Hao

Photosynthetica 2015, 53(4):519-526 | DOI: 10.1007/s11099-015-0147-9

The contribution of photosynthesis to yield improvement is important to know in order to determine future breeding strategies. The objectives of this study were to determine the contribution of photosynthesis and water-use efficiency (WUE) to grain yield improvement of facultative wheat (Triticum aestivum L.) cultivars on the Loess Plateau of China released between 1937 and 2004. The grain yield has increased nearly sevenfold during this period. Surprisingly, these increases were not correlated with the rate of photosynthesis per unit of leaf area when the cultivars were planted and managed in the same environment. The increases were also not...

Ecosystem carbon exchange under different land use on the Qinghai-Tibetan plateau

C. Y. Luo, X. X. Zhu, S. P. Wang, S. J. Cui, Z. H. Zhang, X. Y. Bao, L. Zhao, Y. Li, X. Q. Zhao

Photosynthetica 2015, 53(4):527-536 | DOI: 10.1007/s11099-015-0142-1

There is a great uncertainty about the effect of land use change on grassland ecosystem in the Tibetan Plateau. Net ecosystem carbon exchange (NEE) was measured for native alpine meadow with winter grazing (NAM), abandoned cropland/pasture (APL), perennial Elymus nutans (PEN), and annual oat pasture (AO) on the Tibetan plateau, during the growing seasons in 2009 and 2010 using a transparent chamber technique (Licor-6400). AO significantly decreased annual average NEE by 21.6, 23.7, and 15.7% compared to PEN, NAM, and APL during the growing season in 2010. Compared to PEN, NAM, and APL, AO significantly decreased average ecosystem respiration...

Trade-offs between seedling growth, plant respiration and water-use efficiency in two Mediterranean shrubs Rhamnus alaternus and Rhamnus ludovici-salvatoris

H. El Aou-Ouad, I. Florez-Sarasa, M. Ribas-Carbó, J. Flexas, H. Medrano, J. Gulías

Photosynthetica 2015, 53(4):537-546 | DOI: 10.1007/s11099-015-0141-2

Seedling recruitment is a critical developmental stage in regeneration of plant populations under Mediterranean conditions that strongly depends on water availability. Seed mass and relative growth rate (RGR) may affect the early establishment of seedlings through different physiological processes. Here, we examined the effects of the seed mass and carbon balance on seedling growth under two water regimes in Rhamnus alaternus L. and Rhamnus ludovici-salvatoris, two Mediterranean shrubs, showing a different ability to recruit seedlings. Plant water consumption and biomass accumulation (ΔB) were measured during three periods of the...

Photosynthetic and antioxidant responses to drought during sugarcane ripening

C. R. G. Sales, P. E. R. Marchiori, R. S. Machado, A. V. Fontenele, E. C. Machado, J. A. G. Silveira, R. V. Ribeiro

Photosynthetica 2015, 53(4):547-554 | DOI: 10.1007/s11099-015-0146-x

Water deficit is an important exogenous factor that enhances the influx of sucrose into sugarcane (Saccharum spp.) stem internodes during ripening, when photosynthetic ability in supplying sinks is essential. The aim of this study was to test the hypothesis that drought tolerance in sugarcane is associated with an effective antioxidant protection during the ripening phase that might maintain a favorable redox balance in chloroplasts and protect photosynthesis under drought conditions. Two commercial sugarcane varieties, IACSP94-2094 (tolerant) and IACSP96-2042 (sensitive), with contrasting behavior under water deficit, were subjected to water...

Photosynthetic adaptation and survival strategy of Duvalia velutina in an extremely arid environment

Y. S. Masrahi, T. A. Al-Turki, O. H. Sayed

Photosynthetica 2015, 53(4):555-561 | DOI: 10.1007/s11099-015-0143-0

Leafless Duvalia velutina Lavranos (Apocynaceae) is an arido-active stem succulent common in the arid region southwest of the Arabian Peninsula. This region is characterized by a short wet season with erratic rainfall and a long dry season with high temperature and high irradiance. We investigated the survival strategy of D. velutina by studying nurse association, gas exchange, and chlorophyll fluorescence. Results showed that D. velutina exhibited the strict nurse association with shade for protection against heat and high irradiance. Results also showed that D. velutina is an obligate CAM plant with ample physiotypic plasticity...

Assessing the relationship between photosynthetic C accumulation and symbiotic N nutrition in leaves of field-grown nodulated cowpea (Vigna unguiculata L. Walp.) genotypes

A. K. Belane, F. D. Dakora

Photosynthetica 2015, 53(4):562-571 | DOI: 10.1007/s11099-015-0144-z

This study evaluated the relationship between photosynthetic carbon accumulation and symbiotic nitrogen nutrition in young fully expanded leaves of 30 nodulated cowpea genotypes grown in the field at Manga, Ghana, in 2005 and 2006. Estimates of fixed-N in photosynthetic leaves revealed greater symbiotic N in genotypes with higher photosynthetic rates and increased leaf transpiration rate/efficiency. There was also greater C accumulation in genotypes with higher symbiotic N and/or total N. Additionally, genotypes with high contents of C per unit of leaf total N exhibited greater C per unit of leaf N-fixed. The C/N and C/Rubisco-N ratios were generally...

Physiological responses of halophytic C₄ grass Aeluropus littoralis to salinity and arbuscular mycorrhizal fungi colonization

R. Hajiboland, F. Dashtebani, N. Aliasgharzad

Photosynthetica 2015, 53(4):572-584 | DOI: 10.1007/s11099-015-0131-4

The halophytic C₄ grass, Aeluropus littoralis, was cultivated under low (50 mM) and high (200 mM) NaCl salinity and inoculated with the arbuscular mycorrhizal fungi (AMF) Claroideoglomus etunicatum in a sand culture medium for 20 weeks. Shoot and root dry mass increased under salinity conditions up to 24 and 86%, respectively. Although the root colonization rate significantly decreased in the presence of salt, AMF-colonized (+AMF) plants had higher biomass compared with plants without AMF colonization (-AMF) only under saline conditions. Net CO₂ assimilation rate increased significantly by both salinity levels despite...

Girdling-induced Alhagi sparsifolia senescence and chlorophyll fluorescence changes

G. L. Tang, X. Y. Li, L. S. Lin, F. J. Zeng, Z. Y. Gu

Photosynthetica 2015, 53(4):585-596 | DOI: 10.1007/s11099-015-0148-8

Senescence constitutes the final stage of a plant organ and tissue development and is a subject to gene control and strict regulation. By the late growing season, when Alhagi sparsifolia entered the natural senescence period, a girdling treatment was carried out on the phloem to increase the sugar content in leaves and to investigate carbohydrate-induced leaf senescence. After the semi-girdling and full-girdling treatment, organic matter could not leave leaves due to the destruction of sieve tubes. This led to constantly increasing sugar contents in leaves. Girdling was shown to greatly accelerate the senescence of plants. In girdled leaves,...

Morphoanatomy and ecophysiology of tree seedlings in semideciduous forest during high-light acclimation in nursery

A. K. Calzavara, E. Bianchini, T. Mazzanatti, H. C. Oliveira, R. Stolf-Moreira, J. A. Pimenta

Photosynthetica 2015, 53(4):597-608 | DOI: 10.1007/s11099-015-0151-0

The recomposition of deforested environments demands the acclimation of seedlings in nurseries. This process induces changes in physiological, anatomical, and morphological traits of plants, favouring their establishment after transplantation to the field. The present study aimed to verify the influence of full-sun acclimation on seedling hardiness. For the purpose, leaf gas-exchange, plant anatomical and morphological parameters of three tree species [Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae), Croton floribundus Spreng. (Euphorbiaceae), and Cecropia pachystachya Trecul (Urticaceae)], which are used for reforestation in...

Selenium improves photosynthesis and protects photosystem II in pear (Pyrus bretschneideri), grape (Vitis vinifera), and peach (Prunus persica)

T. Feng, S. S. Chen, D. Q. Gao, G. Q. Liu, H. X. Bai, A. Li, L. X. Peng, Z. Y. Ren

Photosynthetica 2015, 53(4):609-612 | DOI: 10.1007/s11099-015-0118-1

The effects of selenium on photosynthesis and Chl fluorescence in pear, grape, and peach were analyzed. The foliar spray of amino acid-chelated selenium solution was performed soon after fruit setting, totally six times, with an interval of ten days. After seven days from the last spray, the leaves in the middle of shoots were examined. Foliar spray of selenium increased the net photosynthetic rate in pear, grape, and peach. In contrast, the treatment decreased stomatal conductance, transpiration rate, and substomatal CO₂ concentration in all the three species. The selenium treatment improved the maximum quantum yield of PSII, effective...

Photosynthesis parameters during acclimatization of in vitro-grown olive plantlets

A. Chaari-Rkhis, M. Maalej, A. Chelli-Chaabouni, L. Fki, N. Drira

Photosynthetica 2015, 53(4):613-616 | DOI: 10.1007/s11099-015-0138-x

Monitoring some parameters would help to overcome the difficulties that can affect in vitro-grown plants during the crucial step of their acclimatization. Thus, after the determination of net photosynthesis and other parameters during acclimatization of in vitro-grown olive plantlets, we concluded that three months after the transfer to ex vitro, the in vitro-grown olive plants become well acclimated. In fact, even though the net photosynthesis, relatively high in vitro, recorded low values after 15 d from the transfer, it reverted back to its standard rates after 180 d of acclimatization. Transpiration and stomatal...

Effect of light intensity on the age dependence of nonphotochemical fluorescence quenching in wheat leaf

T. V. Nesterenko, V. N. Shikhov, A. A. Tikhomirov

Photosynthetica 2015, 53(4):617-620 | DOI: 10.1007/s11099-015-0133-2

The effects of actinic light (AL) intensity on the age dependence of nonphotochemical fluorescence quenching (q_N) and effective quantum yield in PSII (Φ_PSII) were studied in continuously illuminated wheat leaves of the upper tier. Regular changes were revealed in both age dependence of q_N at elevated AL intensities and light curves of q_N. These changes are related to alterations in strategies of redistribution and use of absorbed light energy by the photosynthetic apparatus at different stages of wheat leaf development. Unlike Φ_PSII, q_N as a parameter was more sensitive to the...

In vivo evaluation of the high-irradiance effects on PSII activity in photosynthetic stems of Hexinia polydichotoma

L. Li, Z. Zhou, J. Liang, R. Lv

Photosynthetica 2015, 53(4):621-624 | DOI: 10.1007/s11099-015-0136-z

Green photosynthetic stems are often responsible for photosynthesis due to the reduction of leaves in arid and hot climates. We studied the response of PSII activity to high irradiance in the photosynthetic stems of Hexinia polydichotoma in the Taklimakan Desert by analysis of the fast fluorescence transients (OJIP). Leaf clips of a chlorophyll fluorometer were used in conjunction with a sponge with a 4-mm-width groove to prevent light leakage for precise in vivo measurements. High irradiance reduced performance indices, illustrating the photoinhibition of PSII to some extent. However, the decrease in active reaction centers (RC) per...

Proteomic study reveals photosynthesis as downstream of both MAP kinase and cAMP signaling pathways in Chlamydomonas reinhardtii

C. Lee, J. K. Rhee, D. G. Kim, Y. E. Choi

Photosynthetica 2015, 53(4):625-629 | DOI: 10.1007/s11099-015-0128-z

Previously, our data indicated that both cAMP and MAP kinase signaling play important roles in microalgal physiology as well as in lipid or carotenoid biosynthesis. In order to understand downstream genes of these signaling pathways, we employed proteomics approach. Both signal pathways were first altered with specific signaling inhibitors or modulators. Treatment of specific inhibitors changed microalgal size and increased lipid contents. With the microalgal cells after treatments of specific signaling inhibitor or modulators, we performed the proteomics analysis to identify downstream genes responsible for these phenotypes. Interestingly, multiple...

Changes in plant growth and photosynthetic performance of Zizania latifolia exposed to different phosphorus concentrations under hydroponic condition

N. Yan, Y. L. Zhang, H. M. Xue, X. H. Zhang, Z. D. Wang, L. Y. Shi, D. P. Guo

Photosynthetica 2015, 53(4):630-635 | DOI: 10.1007/s11099-015-0149-7

The effects of phosphate concentration on plant growth and photosynthetic performance were examined in leaves of Zizania latifolia. Plants were grown for four weeks in a solution containing 0, 0.16, 0.64, and 2.56 mM orthophosphate. The results showed that the highest net photosynthetic rate (P _N) was achieved at 0.64 mM orthophosphate, which corresponded to the maximum content of organic phosphorus in leaves. Low phosphorus (low-P) content in the culture solution inhibited plant growth, affecting plant height, leaf length, leaf number, tiller number, and fresh mass of leaf, sheath, culm, root, and total plant. In addition,...

Robert Simpson Loomis

M. A. El-Sharkawy

Photosynthetica 2015, 53(4):636-640 | DOI: 10.1007/s11099-015-0176-4