共查询到20条相似文献,搜索用时 46 毫秒
1.
Jianming Gao Yong Zhang Chunguo Wang Shougong Zhang Liwang Qi Wenqin Song 《New Forests》2009,37(3):333-344
Amplified fragment length polymorphism (AFLP) was used in genetic fingerprinting of 22 elite Chinese Populus deltoides and Populus × canadensis accessions. The results indicated that each of the nine AFLP primer pairs selected generated fingerprint profiles that were
unique to each of the accessions. Therefore, each accession was definitively identified by any of the nine primer pairs. Furthermore,
the inter-accession genetic relationships inferred based on 461 polymorphic fragments from the nine AFLP primer pairs were
largely consistent with phylogenetic relationships based on morphologic traits. Bootstrap analysis showed that three AFLP
primer pairs were required to obtain genetic similarity values with a maximum CV of 10% while 10 AFLP primer pairs could give
a maximum CV of 5%. Thus, AFLP can readily be applied for a rapid and accurate evaluation of the degree of similarity between
poplar cultivars. In this study, the number of AFLP fragments used was sufficient to establish a reliable estimate of genetic
similarity among accessions, with a maximum CV of 5.12%. Therefore, the information on the genetic relationships among the
poplar accessions generated in this study in connection with knowledge on agronomic traits may have an impact on poplar breeding
and planting in China. 相似文献
2.
Soil microbes may be critical players in determining the allelopathic potential of some plants. Low levels of plant community biodiversity in Eucalyptus plantations have been attributed to the allelopathic potential of these tree species. The role of soil microbes in the allelopathic effect of leaf leachates of the hybrid tree Eucalyptus grandis × E. urophylla, was tested in Petri dish assays with Brassica chinensis as a receiver plant. Soils were collected from either a local garden (soil A) or a Eucalyptus plantation (soil B) and half of each soil was sterilized to remove microbes. These soils were then treated with E. grandis × E. urophylla leachates for 0–72 h. Seed germination of B. chinensis was significantly inhibited in soils treated with leaf leachates relative to untreated soils. The inhibitory effect of the leaf leachates was more pronounced in sterilized soils. Total phenolic content was obvious lower in nonsterile leachate-treated soils than in sterile soils. Biomass of B. chinensis was negatively correlated with the total phenolic content in soils. Our findings suggest that soil microbes can alleviate the allelopathic potential of Eucalyptus and thereby its negative impact on plant growth. 相似文献
3.
E. G. Mendonça M. G. A. Oliveira L. E. Visôtto R. N. C. Guedes 《Journal of pest science》2012,85(1):117-123
Proteinase inhibitors are currently targeted as potential insect control agents, but adaptation to proteinase inhibitors is
a recognized limitation to such approach requiring the understanding of how phytophagous species can cope with such compounds.
The velvetbean caterpillar (Anticarsia gemmatalis) is a key pest of soybean and well-adapted to its host proteinase inhibitors, which is rich in serine-proteinase inhibitors,
particularly trypsin-like proteinase inhibitors. As the expression of cysteine proteinases in the midgut of the velvetbean
caterpillar is a potential adaptation to circumvent its host defense, we assessed and characterized the digestive cysteine-proteinase
activity from velvetbean caterpillars. Significant soluble and membrane-bound proteolytic activity was obtained and was consistent
with those of cysteine proteinases based on the substrate and inhibitors used for their characterization. The K
m and V
max values obtained were 2.35 ± 0.50 mM and 40.89 ± 6.68 nmol min−1 mg−1 for the soluble proteinases and 0.33 ± 0.03 mM and 24.54 ± 0.67 nmol min−1 mg−1 for the membrane-bound proteinases, range of values also consistent with cysteine proteinases. Therefore, the proteolytic
activity observed in the velvetbean caterpillar midgut is consistent with that of cysteine proteinases providing preliminary
support for the contention of their potential involvement mitigating the negative effects of serine-protease inhibitors in
this species. 相似文献
4.
Xudong He Fagen Li Mei Li Qijie Weng Jisen Shi Xiaoyong Mo Siming Gan 《New Forests》2012,43(3):383-394
Interspecific hybrids of Eucalyptus urophylla S. T. Blake × E. tereticornis Smith were used for quantitative genetic analysis of cold hardiness (CH) and growth traits height (H), diameter at breast height (D) and volume (V) at 0.5, 1.5, 2.5 and 4 years of age. The effect of E. tereticornis male variance was significant (P < 0.05) for CH as well as 2.5- and 4-year-old growth except for H
4, and E. urophylla female × E. tereticornis male interaction was significant for 0.5- and 1.5-year-old growth and CH except for CH
0.5, whereas E. urophylla female effect was not significant for the majority of traits analyzed. Both additive and dominance gene action were present
in the genetics of all the traits measured at most ages, indicating that those traits may be improved by hybrid breeding.
The σ
D
2/σ
A
2 ratios tended to decline after 1.5 years of age in CH and growth traits, implying that breeding value predictions derived from older performance might be more reliable. Estimates
of narrow-sense heritability (h
2
) for CH and growth ranged from 0.03 ± 0.05 to 0.28 ± 0.13, depending on trait and age. Additive genetic correlations between CH and V were 0.28 ± 0.48 and 0.69 ± 0.30 at ages 1.5 and 2.5, respectively, suggesting that selection for growth would cause a favorable
increase in cold hardiness in E. urophylla × E. tereticornis hybrids. 相似文献
5.
Five tannin-related compounds – gallic acid, flavogallonic acid dilactone, valoneic acid dilactone, gallagyldilactone, ellagic acid – were isolated from the heartwood of Shorea laeviforia, and the inhibitory activity of each against rat liver 5-reductase was evaluated. Valoneic acid dilactone and gallagyldilactone exhibited positive inhibitory activity, but gallic acid and ellagic acid did not. Flavogallonic acid dilactone stimulated 5-reductase activity, even though this compound is structurally similar to valoneic acid dilactone. The kinetic study of valoneic acid dilactone and gallagyldilactone indicated that the inhibitory behavior of 5-reductase were not competitive against the substrate (testosterone) and were partially competitive against the cofactor (NADPH). Additionally, double inhibition analysis of valoneic acid dilactone and NADP+ showed synergetic inhibition. These results suggested that neither valoneic acid dilactone nor gallagyldilactone can affect the binding of testosterone but that either compound could interact with an enzyme–NADP+ complex to inhibit 5-reductase. 相似文献
6.
The lethal and sublethal effects of chlorantraniliprole against Spodoptera exigua (Hübner) were evaluated under laboratory conditions by oral exposure of neonate larvae to the compound. The 72 h LC50 value of this insecticide to S. exigua was found to be 12.747 μg l−1. A progressive larval mortality of 24.32% for LC30 treatment and 42.61% for LC50 treatment was observed from 4th to 6th day after exposure, which resulted in the reduced pupation rates in exposure groups.
The sublethal effects of this chemical were indicated by prolongation of larval period, the increase of pupal weight and decrease
in hatch rate of egg. Chlorantraniliprole at LC30 and LC50 rate significantly delayed larval development; the developmental duration of surviving larvae was extended for 22.5 and 28.6%,
respectively, compared with that of control group. LC30 treatment increased the mean weight of pupa and induced to the production of heavier pupa (>150 mg). In LC50 treatment, heavier pupa also showed up but the mean weight of pupa was not influenced. The egg hatch rate in LC50 group was significant lower than that in control and LC30 groups. No significant differences in pupal duration, emergence rate, sex ratio, egg number per female, and longevity of
adults were observed among treatments. Chlorantraniliprole had exceptional activity against S. exigua according to concentration–response bioassay in laboratory, and the toxicities were primarily resulted from immediate lethality. 相似文献
7.
W. A. Shehata S. S. Abou-Elkhair A. A. Youssef F. N. Nasr 《Journal of pest science》2003,76(6):155-158
Abstract The biology of two important lepidopterous pests, Prays oleae Bernard and Palpita unionalis Hübner, was studied. The target pests were reared on olive plants, Oleae europaea L. (Oleaceae) under laboratory conditions for two successive generations, from March to June 2002. For P. oleae, the duration of larval stage development in the first generation was 21.4 ± 0.18 days at 19.3–20.9 °C, 65–68 % R.H, while in the second generation it was 14.8 ± 0.10 days at 20.8–24.2 °C, 65–69 % R.H. The number of eggs laid per female ranged from 58 to 109 eggs in the first generation, and from 47 to 113 in the second. The larval stage duration of P. unionalis was 16.3 ± 0.12 days at 16.8–22.9 °C, 65–69 % R.H. and 15.5 ± 0.12 days at 21.6–25.5 °C, 66–69 % R.H. for the first and second generations, respectively. Also, the number of eggs laid per female ranged from 630 to 653 eggs, and from 425 to 493 eggs in the second generation under the same previous laboratory conditions. P. oleae laid eggs at night mostly singly on flower-buds, more on the calyx. than on the petals. The larvae mined on leaves and damaged groups of flowers. P. unionalis adults were active at night, laid eggs singly at twilight usually on the lower surface of foliage. Larvae fed on leaves spinning several leaves together to form shelter for the pupa. 相似文献
8.
John Mukuka Olaf Strauch Christopher Hoppe Ralf-Udo Ehlers 《Journal of pest science》2010,83(3):281-287
Entomopathogenic nematodes of the genus Heterorhabditis are a suitable alternative to chemical insecticides because of their high control effect against insects in cryptic environments
and their environmental safety. The availability of H. bacteriophora hybrid strains with increased tolerance to environmental extremes could be a driving force for a more widespread use of nematode-based
plant protection products. However, increase in heat and desiccation tolerance of hybrid strains could compromise their fitness
regarding virulence, host penetration and reproductive capacity. The fitness of heat and desiccation tolerant hybrid strains
was compared to the commercial strain EN 01. Only the heat tolerant strains were superior or similar in fitness to strain
EN 01. The strains with increased desiccation tolerance were usually less fit, a possible result of a trade-off effect of
selection for desiccation tolerance. Hybrid strains selected for enhanced tolerance after an adaptation to stress were generally
better in fitness ranking compared to those for which adaptation prior to stress exposure was excluded. This might be a result
of pleitropy. Host penetration and virulence was not correlated. The commercial strain had the highest reproduction per mean
number of nematodes penetrating the host insect, which is a result of automatic selection of inbred lines with high reproduction
potential during the commercial production process in liquid culture. 相似文献
9.
Leaf functional traits are adaptations that enable plants to live under different environmental conditions. This study aims to evaluate the differences in leaf functional traits between red and green leaves of two evergreen shrubs Photinia × fraseri and Osmanthus fragrans. Specific areas of red leaves are higher than that of green leaves in both species. Thus, the material investment per unit area and per lamina of red leaves is significantly lower than that of green leaves, implying an utmost effort of red leaves to increase light capture and use efficiency because of their low leaf-chlorophyll concentration. The higher petiole length of green leaves compared with that of red leaves indicates that adult green leaves may have large fractional biomass allocation to support the lamina structures in capturing light with maximum efficiency and obtaining a high growth rate. The high range of the phenotypic plasticity of leaf size, leaf thickness, single-leaf wet and dry weights, and leaf moisture of green leaves may be beneficial in achieving efficient control of water loss and nutrient deprivation. The high range of phenotypic plasticity of leaf chlorophyll concentration of red leaves may be advantageous in increasing resource (especially light) capture and use efficiency because this leaf type is juvenile in the growth stage and has low leaf-chlorophyll concentration. 相似文献
10.
Defence proteins are a kind of chemical defence compounds. They play a key role in plant restraining biotic and abiotic harm. To illuminate activities of some defense proteins associated with age or plant family of larch, the larch needles were collected from two different families of Korean larch, Larix olgensis and a hybrid larch, L. kaempferi × L. gmelinii, respectively, and then the activities of defence proteins in those were tested using a UV spectrophotometry. The results showed that the activities of protective enzymes at the16-/17- and 19-year-age groups were higher than those at the other age groups in the both larch species. While the activities of polyphenol oxidase (PPO) at the 16-/17-year-age group and phenylalanine ammonia-lyase (PAL) and protease inhibitors at the 19-year-age group were the highest among all age groups. Then, compared with L. olgensis, the hybrid larch had significant effects on the activities of protective enzymes. The effects of plant family on the activities of PAL and chymotrypsin inhibitor were significantly different, and then those on the activities of PPO were not significantly different. The effects of the two families in L. olgensis on the activities of trypsin inhibitor (TI) were significantly different, while those in the hybrid larch on the activities of TI were contrary. To conclusions showed that the different age and plant family significantly affected the activities of defence proteins in the needles of two larch species, and then enhanced the larch resistance to pests. These could play a key function in forestry tree genetic improvement and management in future. 相似文献
11.
Cassiana de Oliveira Juliana Degenhardt-Goldbach Gisela Manuela de França Bettencourt Erika Amano Luziane Franciscon Marguerite Quoirin 《林业研究》2017,28(1):29-39
Genetic transformation systems require protocols that allow regenerating transgenic plants from transformed tissues. This study aimed to establish a protocol for indirect organogenesis in leaf explants of a Eucalyptus grandis × E. urophylla AEC 224 clone. During callogenesis stage, several concentrations of NAA and then NAA or 2,4-D combined with TDZ were tested in JADS culture medium for 30 days, followed by subculture of the explants in the regeneration medium, containing 5.0 µM BA and 0.5 µM NAA for another 30 days. In these media, the explant oxidation rate was high (95 %). Thus, in order to reduce oxidation, different culture media were compared: WPM, MS, JADS and modified QL, followed by explant transfer onto regeneration medium. The highest percentage of regeneration and the lowest oxidation rate were achieved on WPM medium. Then, NAA and 2,4-D were tested in combination with TDZ and also TDZ and BA combined with NAA in WPM medium. The most efficient culture media in terms of shoot regeneration were WPM supplemented with 0.25 µM TDZ and 0.1 µM NAA during 30 days for callus induction and then with 5.0 µM BA and 0.5 µM NAA for another 30 days. This protocol yielded a regeneration rate of 43 %, with a low oxidation of tissues. A rooting experiment was conducted using half strength MS medium and comparing three concentrations of IBA (2.46, 4.90 and 7.35 µM). The highest rooting percentage (35 %) was obtained on medium containing 2.46 µM IBA. Once the shoots were rooted, acclimatization in a greenhouse was not challenging and plant survival reached 100 %. 相似文献
12.
Microsporogenesis and flower development in Eucalyptus urophylla × E. grandis were examined using chromosome tableting to provide a method to predict the meiotic stages in this species. Although microsporogenesis was normal, cytokinesis during meiosis of pollen mother cells occurred simultaneously, with strong asynchronism observed in the two different lengths of stamens in a flower bud. In a single flower, the developmental period of microsporogenesis in anthers on the longer stamens was always ahead of those on the shorter stamens. Flower development was also asynchronous at different locations on a branch. Flower buds on the upper side of the branch were larger in diameter than those on the lower side. In addition, a correlation was observed between microsporogenesis development and flower bud diameter growth. The pachytene stage was first observed when the diameter of the flower buds increased to 3.0 mm, and the majority of the meiotic stages were observed when bud diameters ranged from 3.5 to 5.0 mm. This study showed that the developmental stages of microsporogenesis in Eucalyptus urophylla × E. grandis could be distinguished readily, which may be applicable to future breeding studies. 相似文献
13.
The olive is one of the most important crops in Greece as in many Mediterranean countries. Several insects are considered serious pests of the olive crop. In this study, we report two new pests for olive trees in Greece and possibly in the Mediterranean region: the quince moth Euzophera bigella (Zeller) (Lepidoptera: Pyralidae) and the olive leaf gall midge Dasineura oleae (F. Low) (Diptera: Cecidomyiidae). Although E. bigella is not considered a pest of olive trees, in the summer of 2011, the quince moth was recorded for the first time infesting olive trees in several orchards in the rural area of the Municipality of Amphipolis (Region of Central Macedonia). Infestation induced cracking and swelling symptoms on the bark of limbs and the periderm of trunks, accompanied by extensive internal bark necrosis, which caused the desiccation of limbs or even the death of whole trees. D. oleae has been reported infesting olive trees in Greece; however, it was not considered a pest of the crop. In February 2010, extensive infestations by D. oleae were detected in the coastal zone of Elounda, Lassithi (Region of Crete). Infestations were observed on the leaves causing elongate galls and deformations, while in highly infested trees defoliation was reported. Because of the scarceness of these infestations, the results reported in this study are discussed in relation to cases reported from other countries and/or on other crops. In addition, a review of the distribution, biology and control methods of these species is provided in an attempt to summarize the scattered information currently available. 相似文献
14.
Martin Kohler Julia Sohn Gregor Nägele Jürgen Bauhus 《European Journal of Forest Research》2010,129(6):1109-1118
To investigate whether drought tolerance of individual trees can be increased through the provision of more growing space,
trees from a thinning experiment were analysed for reductions in radial growth during drought years and their subsequent recovery.
Tree-ring widths were quantified on increment cores as well as stem discs of 32 trees from stands of a thinning trial established
in 1974 in 27-year-old spruce stands in the Alpine Foreland of Southwest Germany. Three different thinning regimes of the
trial were selected for this study: unthinned control (8 trees), moderate (13 trees) and heavy thinning (11 trees) intensities.
All trees sampled were of a co-dominant to dominant canopy status. The standardisation of growth data was carried out using
the software program ARSTAN (University of Arizona). For the year 1976—a widespread and severe drought year in Germany—we
found year ring widths were not reduced compared to those of the pre-drought years for all treatments. However, we observed
the formation of false year rings and resin ducts for this year in all trees investigated. The drought events in 1992 and
2003 led to severe growth depressions in the year of the drought event in all trees, regardless of previous thinning regimes.
However, the resilience—the recovery of basal area growth in subsequent years—was significantly more rapid in trees from heavily
thinned stands, even if the drought event occurred more than 10 years after the last thinning intervention. This indicates
a shorter stress period for trees with more growing space, which may reduce the susceptibility to secondary pathogens or pest
species such as bark beetles. 相似文献
15.
The effect of Thidiazuron (TDZ), basal media and light quality on adventitious shoot regeneration from in vitro cultured stem of Populus albaxP berolinensis were determined to establish a high efficiency shoot regeneration system from stem explants of P. alba~P berolinensis. Stems ofPopulus alba~P berolinensis were collected from cultured shoots in vitro derived from dormancy buds of 3-year-old seedlings. The stem explants were cultured on MS medium containing 0.02-mg·L-1NAA (naphthaleneacetic acid), and 0.1, 0.3, 0.5 and 1.0 mg·L-1 concentrations of TDZ to determine the effect of TDZ on shoot regeneration. Three basal media, i.e. MS, woody plant medium (WPM) and B5, were used to test their influences of different media on adventitious shoot regeneration. Green, red, blue and yellow plastic films in comparison with florescent light as control were used to observe their effects on shoot regeneration. The results showed that differ- ent concentrations of TDZ had an evident influence on shoot regeneration. Lower concentration of TDZ (0.1 mg·L-1) resulted in more ad- ventitious shoot regeneration and higher concentration of TDZ (〉0.1 mg·L-1) inhibited shoot regeneration. Among different media, MS medium exhibited a high efficiency for shoot regeneration, followed by WPM medium, while B5 medium inhibited shoot regeneration. Normal light and yellow light exhibited better effects on shoot regeneration, compared with other light. 相似文献
16.
The role of plant eIF5A proteins in multiple biological processes, such as protein synthesis regulation, translation elongation, mRNA turnover, programmed cell death and stress tolerance is well known. Toward using these powerful proteins to increase stress tolerance in agricultural plants, in the present study, we cloned and characterized PsneIF5A2 and PsneIF5A4 from young poplar (P. simonii × P. nigra) leaves. The deduced amino acid sequences of PsneIF5A2 and PsneIF5A4 were 98 % similar to each other, and they are orthologs of eIF5A1 in Arabidopsis. In a subcellular localization analysis, PsneIF5A2 and PsneIF5A4 proteins were localized in the nucleus and cytoplasm. qRT-PCR analysis showed that PsneIF5A2 and PsneIF5A4 were transcribed in poplar flowers, stem, leaves, and roots. In addition, they were also induced by abiotic stresses. Transgenic yeast expressing PsneIF5A2 and PsneIF5A4 had increased salt, heavy metal, osmotic, oxidative tolerance. Our results suggest that PsneIF5A2 and PsneIF5A4 are excellent candidates for genetic engineering to improve salt and heavy metal tolerance in agricultural plants. 相似文献
17.
To reveal the multi-generation effects of transgenic Bt cotton on the metabolism of secondary target herbivores, the activities
of digestive and detoxification enzymes in beet armyworm, Spodoptera exigua (Hübner), fed with transgenic Bt (cv. GK-12) vs. non-Bt cotton (cv. Simian-3) for three successive generations were examined.
Significantly lower activities of lipase, carboxylesterase (CarE) and acetylcholinesterase (AChE), and higher activities of
trypsin and total superoxide dismutase (T-SOD) were observed in Bt-fed S. exigua than in non-Bt fed individuals during the three generations. But the activity of amylase did not differ between the Bt-fed
and non-Bt fed S. exigua. Among the three generations of Bt-fed S. exigua, the activities of lipase and trypsin decreased significantly in the second or third generation than in the first generation.
But those of CarE and AChE were increased significantly. Among the three generations of non-Bt fed S. exigua, the activity of lipase was significantly higher in the second and third generations than in the first generation. The increasing
adaptation and fitness of S. exigua after continuous exposure to Bt cotton was supposed to be associated with the enhanced activities of detoxification enzymes.
Measuring multi-generational enzymes activities of S. exigua in response to Bt cotton can provide proofs of its adaptation development, which is suggested to be a mandatory part of risk
assessment of transgenic Bt plants on secondary target herbivores. 相似文献
18.
The optimum conditions for β-thujaplicin production in a Cupressus lusitanica cell suspension culture were investigated. The conditions required for β-thujaplicin production were clearly different from the conditions for cell growth. The initial phosphate concentration and pH did not affect β-thujaplicin production. A total nitrogen source concentration higher than 3.2 mM suppressed production due to the presence of the ammonium ion. β-Thujaplicin production was observed at 95 mg/l without adding the ammonium ion to the medium. Strict control of major inorganic nutrients was not necessary to produce β-thujaplicin. This finding seems to be favorable for future automated production of β-thujaplicin in commercial cell culture plants. 相似文献
19.
Shengkan Chen Qijie Weng Fagen Li Mei Li Changpin Zhou Siming Gan 《Annals of Forest Science》2018,75(1):16
Key message
Growth and wood chemical properties are important pulpwood traits. Their narrow-sense heritability ranged from 0.03 to 0.49 in Eucalyptus urophylla × E. tereticornis hybrids, indicating low to moderate levels of genetic control. Genetic correlations were mostly favorable for simultaneous improvement on growth and wood traits. Additive and non-additive genetic effects should be considered in making a hybrid breeding strategy.Context
Eucalypt hybrids are widely planted for pulpwood production purposes. Genetic variations and correlations for growth and wood chemical traits remain to be explored in Eucalyptus interspecific hybrids.Aims
Our objectives were to clarify the heritability of growth and wood chemical traits and determine the genetic correlations between traits and between trials in E. urophylla × E. tereticornis hybrids.Methods
Two trials of 59 E. urophylla × E. tereticornis hybrids derived from an incomplete factorial mating design were investigated at age 10 for growth (height and diameter) and wood chemical properties (basic density, cellulose content, hemi-cellulose content, lignin content, and syringyl-to-guaiacyl ratio). Mixed linear models were used to estimate genetic parameters.Results
Narrow-sense heritability estimates were 0.13?0.22 in growth and 0.03?0.49 in wood traits, indicating low to moderate levels of additive genetic control. Genetic correlations were mostly positively significant for growth with basic density and cellulose content but negatively significant with hemi-cellulose and lignin contents, being favourablefavorable for pulpwood breeding purpose. Type-B correlations between sites were significant for all the traits except diameter and lignin content.Conclusion
Hybrid superiority warrants the breeding efforts. An appropriate breeding strategy should be able to capture both additive and non-additive genetic effects.20.
Hui Li Huicheng Xie Zilong Du Xianshuang Xing Jie Zhao Jing Guo Xia Liu Shuyong Zhang 《林业研究》2018,29(4):925-931
The declines in soil fertility and productivity in continuously cropped poplar plantations are related to phenolic acid accumulation in the soil. Nitrogen is a vital life element for poplar and whether the accumulation of phenolic acid could influence nitrogen metabolism in poplar and thereby hinder continuous cropping is not clear. In this study, poplar cuttings of Populus × euramericana ‘Neva’ were potted in vermiculite, and phenolic acids at three concentrations (0X, 0.5X and 1.0X) were added according to the actual content (1.0X) in the soil of a second-generation poplar plantation. Each treatment had eight replicates. We measured gas exchange parameters and the activities of key enzymes related to nitrogen metabolism in the leaves. Leaf photosynthetic parameters varied with the concentration of phenolic acids. The net photosynthetic rate (PN) significantly decreased with increasing phenolic acid concentration, and non-stomatal factors might have been the primary limitation for PN. The activities of nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT), as well as the contents of nitrate nitrogen, ammonium nitrogen, and total nitrogen in the leaves decreased with increasing phenolic acid concentration. This was significantly and positively related to PN (P < 0.05). The low concentration of phenolic acids mainly affected the transformation process of NO3? to NO2?, while the high concentration of phenolic acids affected both processes, where NO3? was transferred to NO2? and NH4+ was transferred to glutamine (Gln). Overall, phenolic acid had significant inhibitory effects on the photosynthetic productivity of Populus × euramericana ‘Neva’. This was probably due to its influence on the activities of nitrogen assimilation enzymes, which reduced the amount of amino acids that were translated into protein and enzymes. Improving the absorption and utilization of nitrogen by plants could help to overcome the problems caused by continuous cropping. 相似文献