Effects of different vegetation restoration models on soil microbial biomass in eroded hilly Loess Plateau, China

Vegetation restoration is a key measure to improve the eco-environment in Loess Plateau, China. In order to find the effect of soil microbial biomass under different vegetation restoration models in this region, six trial sites located in Zhifanggou watershed were selected in this study. Results showed that soil microbial biomass, microbial respiration and physical and chemical properties increased apparently. After 30 years of vegetation restoration, soil microbial biomass C, N, P (SMBC, SMBN, SMBP) and microbial respiration, increased by 109.01%–144.22%, 34.17%–117.09%, 31.79%–79.94% and 26.78%–87.59% respectively, as compared with the farmland. However, metabolic quotient declined dramatically by 57.45%–77.49%. Effects of different models of vegetation restoration are different on improving the properties of soil. In general, mixed stands of Pinus tabulaeformis-Amorpha fruticosa and Robinia pseudoacacia-A. fruticosa had the most remarkable effect, followed by R. pseudoacacia and Caragana korshinkii, fallow land and P. tabulaeformis was the lowest. Restoration of mixed forest had greater effective than pure forest in eroded Hilly Loess Plateau. The significant relationships were observed among SMBC, SMBP, microbial respiration, and physical and chemical properties of soil. It was concluded that microbial biomass can be used as indicators of soil quality. __________ Translated from Journal of Natural Resources, 2007, 22(1): 20–27 [译自: 自然资源学报]     

Investigation of anti-salt stress on tetraploid Robinia pseudoacacia

Tetraploid Robinia pseudoacacia was used as a main test material and diploid R. pseudoacacia was used as the control. The indices of shape, physiology and biochemistry, photosynthesis and anatomic structure of the young plants were investigated under salt stress (NaCl and Na₂SO₄). The treatment time was 30 d with an interval time of 7 d. Before and after treatment, the indices were measured. Results show that: 1) the growth of diploid R. pseudoacacia inhibited an evident symptom of salt damage and the leaf moisture content was lower under salt stress than that of control. But the tetraploid R. pseudoacacia was contrary. 2) The relative electric conductivity and proline (Pro) of tetraploid R. pseudoacacia increased slightly and had no significant difference compared with its control, which was contrary to diploid R. pseudoacacia. At the same time, three protective enzymes including perocidase (POD), superoxide (SOD) and catalase (CAT) kept higher activities at a post stage of salt stress to tetraploid R. pseudoacacia, which enhanced its anti-salt characteristics. Diploid R. pseudoacacia was sensitive to salt and had contrary information. 3) Salt stress had little influence to photosynthesis of tetraploid R. pseudoacacia. The net photosynthetic rate (P _n) and intercellular CO₂ concentration (C_i) had no significant changes, but those of diploid R. pseudoacacia decreased singificantly. 4) After salt stress, the anatomic structure of tetraploid R. pseudoacacia had a positive reaction, including the palisade parenchyma of diachyma, was prolonged and arranged more tightly. The spongy parenchyma was shrunk and was arranged tightly, which was contrary with diploid R. pseudoacacia. These data demonstrate that tetraploid R. pseudoacacia had superior anti-salt performance. __________ Translated from Journal of Plant Ecology, 2008, 32(3): 654–663 [译自: 植物生态学报]     

A model for vertical distribution of fine roots in Robinia pseudoacacia plantations on the Loess Plateau

Based on a detailed investigation of vertical distributions of fine roots in Robinia pseudoacacia plantations at the Ansai Soil and Water Conservation Station, Shaanxi Province, a model was developed for the deep distribution of fine roots of R. pseudoacacia, which reflects the growth of fine roots affected by the mixed process of infiltration water and deep soil water. The maximum depth of the distribution h _max and the depth of the highest fine root density (FRD) h _p were determined and the maximum depth of infiltration water supplied for fine root growth h _q could also be calculated, h _q was considered as the approximate boundary between infiltration water and deep soil water in support of the growth of fine roots. According to the model, the soil water of R. pseudoacacia woodland in the profile could be classified into three layers: the first layer from the soil surface to h _p was the active water exchange layer, very much affected by precipitation; the second was the soil water attenuation layer, between h _p and h _q and largely affected by the vertical distribution of fine roots; the third was the relatively stable soil water layer below h _q, below which soil water did not change much. The percentage of infiltration water supplied for the growth of fine roots reached a level of 88.32% on the shaded slopes and 85.21% on sunny slopes. This indicated infiltration of precipitation played a crucial role in the growth of R. pseudoacacia in the gully region of the Loess Plateau. The research of interaction between the distribution of fine roots and soil water in the profile will help to explain the reasons for the complete drying out of soils and provide a theoretical basis for continuing the policy of matching tree species with sites on the Loess Plateau. Translated from Scientia Silvae Sinicae, 2006, 42(6): 40–48 [译自: 林业科学]     

Characteristics of carbon and nitrogen of soil microbial biomass and their relationships with soil nutrients in Cunninghamia lanceolata plantations

The soil microbial biomass and nutrient status under the native broadleaved forest and Cunninghamia lanceolata plantations at the Huitong National Research Station of Forest Ecosystem (in Hunan Province, midland of China) were examined in this study. The results showed that after the native broadleaved forest was replaced by mono-cultured C. lanceolata or C. lanceolata, soil microbial biomass and nutrient pool decreased significantly. In the 0–10 cm soil layer, the concentrations of soil microbial carbon and nitrogen in the broadleaved forest were 800.5 and 84.5 mg/kg, respectively. These were 1.90 and 1.03 times as much as those in the first rotation of the C. lanceolata plantation, and 2.16 and 1.27 times as much as those in the second rotation of the plantation, respectively. While in the 10–20 cm soil layer, the microbial carbon and nitrogen in the broadleaved forest were 475.4 and 63.3 mg/kg, respectively. These were 1.86 and 1.60 times as much as those in the first rotation, and 2.11 and 1.76 times as much as those in the second rotation, respectively. Soil nutrient pools, such as total nitrogen, total potassium, NH₄ ⁺-N, and available potassium, also declined after the C. lanceolata plantation replaced the native broadleaved forest, or Chinese fir was planted continuously. Less litter and slower decay rate in pure Chinese fir plantation were the crucial factors leading to the decrease of soil microbial biomass and nutrient pool in this area. Human disturbance, especially slash-burning and site preparation, was another factor leading to the decrease. There were significant positive correlations between soil microbial carbon and nitrogen and soil nutrients. To improve soil quality and maintain sustainable productivity, some measures, including planting mixed conifer with hardwood, preserving residues after harvest, and adopting scientific site preparation, should be taken. Translated from Chinese Journal of Applied Ecology, 2006, 17(12): 2,292–2,296 [译自: 应用生态学报]     

匈牙利刺槐（（Robinia pseudoacacia L.）林的经营研究

匈牙利刺槐（（Robinia pseudoacacia L.)是在17世纪初从北美引入到欧洲的第个森林树种。在匈牙利，刺槐是非常重要的速生树种，为经济和生态目的，可以成功营造刺槐人工林。结合该树种的生长特点选择营林措施，可以最大限度的提高刺槐人工林的成活率和生产力。本文根据林分结构和森林产量长期实验林的研究成果，提出了刺槐林的抚育作业次序。制定好的营林计划和模式将会培育出效益刺槐林，并能使土地经营者更好地接受该树种。同时，刺槐也是一个非常有用的能源生产树种，本文展示了对这方面的研究成果。图2表1参8。     

Propagation methods for black locust (Robinia pseudoacacia L.) improvement in Hungary

Black locust (Robinia pseudoacacia L.) is one of the most important stand-forming tree species in Hungary and its importance is increasing in many countries. Black locust plants are commonly produced by two methods, by seed and by root cuttings. Tissue culture propagation can be considered as a relatively new method. Growing trees from seed is a relatively simple method for reliably producing seedlings on a large scale under a variety of circumstances. Mechanization of the method is easy and the production cost is relatively low. Propagation from root cuttings and tissue culture are valuable for reproduction of superior individuals or varieties. By applying these methods, superior traits of the selected trees can be preserved in the clones. Recent experiments demonstrated that micropropagated trees could be successfully transplanted into soil, hardened and grown in the field. Biography: Karoly Redei (1952), male, doctor, deputy director general of Hungarian Forest Research Institute H-1023 Budapest, Frankel Leó Str. 42 44, HUNGARY. Responsible editor: Chal Ruihai     

Effects of afforestation on microbial biomass C and respiration in eroded soils of Turkey

ABSTRACT

Soil erosion is a major socioeconomic and environmental problem in Turkey. Almost 86% of the land in Turkey has suffered various degrees of soil erosion. The objective of this study was to determine whether differences in tree species affect soil characteristics and microbial activity in degraded soils. Results from this study showed that organic C (C_org) was highest in the black locust soil at 0–20 cm depth and lowest in the bare land. Microbial biomass C (C_mic) increased in the order black locust > Scotch pine > bare land at two soil depths. One-way ANOVA demonstrated that afforested soils contain significantly higher microbial biomass C than those in the bare land soils. Microbial quotient (C_mic/C_org) of soils are positively influenced by afforestation as the bare land soils exhibited lower microbial quotient than the associated Scotch pine and black locust soils. Microbial communities in black locust soils were energetically more efficient—had a lower metabolic quotient (qCO₂)—with a higher C_mic/C_org compared to those in Scotch pine soils. However, the microbial quotient in our study was still below range and cannot reach equilibrium again 15 yr after afforestation. Restoration of degraded lands could be a long-term process from microbial activity in the observed regions.     

Variation in germination character of Robinia pseudoacacia L. (Leguminosae) seeds at individual tree level

To demonstrate the seed dormancy and germination characters of Robinia pseudoacacia L., an exotic tall tree species in Japan, we applied scarification, cold stratification, diurnal thermal regime, heat shock, and/or winter weathering treatments to the seeds. These characters differed markedly among three seed sources (Trees K, B, and I). Scarification revealed that most seeds from Tree K showed physical dormancy, whereas those from Tree B had no physical dormancy. The seeds from Tree I showed weak physical dormancy so that the seeds eventually germinate without any treatments as time goes by. The physical dormancy in Tree K was broken by a long, high heat shock treatment. The results imply that seeds from Tree K respond to fire in natural conditions. Seeds from Tree I responded to a wide range of thermal regimes, except for long, high heat shock. In contrast, most seeds from Tree B absorbed water during cold stratification and some germinated. However, many seeds from Tree B died in the soil during the winter, presumably because of microbial and fungal infections. Seeds from Trees I and B acquired physical dormancy by weathering during the winter, implying that seedpods that remain in the crown function as an aerial seed bank. R. pseudoacacia may be able to produce various levels in dormancy with respect to the winter condition.     

栽培措施对四倍体刺槐生物量的影响

为了探索根龄、栽培密度和刈割方法对四倍体刺槐饲料林生物量及再生能力的影响,确定合理的饲料林栽培模式,对不同根龄、不同密度、不同刈割周期及留茬高度和不同刈割工具及刈割部位的当年生林分从总质量、叶质量等生物量指标方面进行了测量分析.结果表明:四倍体刺槐饲料林生物量随根龄的增长而增加;其合理的栽培密度为0.4 m×0.8 m...     

Effect of inoculation with ecto- and arbuscular mycorrhizae and Rhizobium on the growth and nitrogen fixation by black locust,Robinia pseudoacacia

Experiments were made to determine the effect of inoculation withRhizobium, the ectomycorrhizal fungus Hebelomamesophasem and the arbuscular mycorrhizal fungus Glomuscaledonium on the growth and nitrogen fixation of black locust(Robinia pseudoacacia Linn.) seedlings grown invitro and in pot culture. The results showed that both mycorrhizalfungi and Rhizobium stimulated the growth and nitrogenfixing ability of inoculated seedlings. Inoculation with all three microbestogether produced the most beneficial effects on nitrogen fixation, mycorrhizaldevelopment and seedling growth.     

Agrobacterium tumefaciens-mediated GUS gene transformation of Robinia pseudoacacia ‘Idaho’

Based on the plant regeneration system, a GUS gene transformation system to Idaho locust (Robinia pseudoacacia ‘Idaho’) mediated by Agrobacterium tumefaciens was established. The successful transformation was confirmed by regenerating the shoots from the infected leaves in the presence of hygromysin; by histochemical X-gluc assays of β-glucuronidase (GUS) and by PCR and PCR-Southern blotting analysis. The ratio of positive transgenic plants is 5.8% (5 out of 86 plants). With this system, the target gene DREB was introduced into the leaves of Idaho locust. The transgenic plants regenerated, which was verified by PCR-Southern blot-ting. It is suggested that the transformation system could be a new, simple, reliable and practical route to gene transformation of R. pseudoacacia ‘Idaho’ mediated with A. tumefaciens.     

土壤微生物生物量碳研究进展综述

土壤微生物量碳是土壤碳素转化的重要环节,也是土壤有效碳库的重要组成部分。文章从土壤微生物量碳的影响因素、测定、周转以及土壤微生物量碳与土壤有机碳的关系四个方面综述了土壤微生物生物量碳的研究进展。同时,为今后这方面的研究重点及发展方向提供了参考。     

Reproduction of a Robinia pseudoacacia population in a coastal Pinus thunbergii windbreak along the Kujukurihama Coast, Japan

We investigated reproduction of the clonal tree Robinia pseudoacacia in a Pinus thunbergii windbreak. Microsatellite polymorphism analysis revealed that asexual reproduction through horizontal root elongation and ramet formation was the primary mode of reproduction in this population. Germination experiments indicated that the inability of established genets to produce viable seeds inhibited sexual reproduction. The boundaries between genet areas were relatively distinct, indicating that ramets within genets spatially excluded one another. Analyses of the number of annual rings and thickness of excavated horizontal roots provided new insight regarding photosynthate transfer through horizontal roots. The number of annual rings and thickness were highest for horizontal roots near the base of ramets and decreased along portions far from ramets. This result indicates that the new horizontal root is supplied with photosynthate from the mother ramet for a few years only, and that resource translocation between neighboring ramets within the same clone ceases after several years. Hypotheses about horizontal root expansion and cessation were considered to explain the exclusive distribution pattern of the horizontal root between genets.     

Correlation of eco-hydrographic benefit and height increment of Robinia pseudoacacia stand with climatic environmental factors in Yellow River Delta Wetland of China

The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wetland, Shandong Province, China. The correlation of height increment of R. pseudoacacia with nine climate factors such as light, water, heat, etc. was analyzed by stepwise regression analysis. The results showed that the amounts of runoff and sediment in clearcut area of R. pseudoacacia were 53.9%–150.8% and 172.8%–387.1% higher than that in Robinia pseudoacacia plantation, respectively. The runoff peak value in R. pseudoacacia stand was obviously lower than that in clerarcut area, meantime, the occurrence of runoff peak in R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%–25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment of R. pseudoacacia, followed by water and heat factors. Foundation project: Subsidized by the National “11th Five Year” Plan of Science and technology (2006BAD26B06, 2006BAD03A1205) and Ecological Restore Project of Water Resources Ministry of China (2006-2008).     

Effect of auxins (IBA and NAA) and season on rooting of juvenile and mature hardwood cuttings of Robinia pseudoacacia and Grewia optiva

Juvenile (2 year old trees) and mature hardwood (15 year old trees) cuttings of Robinia pseudoacacia and Grewia optiva were tested for their capacity to form roots. Cuttings were prepared in spring, monsoon and winter seasons and treated with different concentrations (250, 500 and 750 mg/l) of IBA and NAA. These were planted in a mist chamber maintained at 25±1°C with relative humidity >70%. Juvenile cuttings of both species rooted significantly better than mature hardwood cuttings in all three seasons, and the age effect was more pronounced in auxin treated cuttings. The highest rooting in juvenile (83.3%) and mature (66.6%) cuttings was observed with the NAA (500 mg/l) treatment in R. pseudoacacia during the spring season. In G. optiva, IBA (250 mg/l) in the monsoon season was most effective and yielding a maximum of 80% and 70% rooting in juvenile and mature cuttings, respectively. Auxin treatments also significantly enhanced the number of roots, root length, leaf number and leaf area. Statistical analysis of data revealed that interactions between age, season and treatments were significant at P <0.05 level for R. pseudoacacia and non-significant for G. optiva.     

Regeneration and gene transformation systems of Robinia pseudoacacia ‘Idaho’ mediated by Agrobacterium tumefaciens

Robinia pseudoacacia ‘Idaho’ is one of several multi-purpose trees used in ornamental, soil and water conservation, fodder and nectar sources. Plant abiotic stress tolerance transformed by genes could meet the requirements for reclamation of arid or alkalid lands and vegetation restoration. For this paper, we studied the effects of auxin and cytokine on Idaho locust in vitro regeneration and the establishment of gene transformation systems for plants mediated by Agrobacterium tumefaciens. Results showed that the ratios of cytokinin and auxin were the major factors affecting adventitious bud differentiation on a MS medium; the concentration of 0.5 mg&#8226;L^–1 6-BA benefitted callus proliferation and 0.25 mg&#8226;L^–1 IBA promoted shoot rooting; however, a higher IBA concentration will inhibit rooting. The most effective antitoxin for screening transgenic Idaho locust shoots was G418 and the most sensitive concentra-tion of it was 8 mg&#8226;L^–1.     

沛县沙土地刺槐新无性系造林对比试验

１９９２年引进刺槐新无性系２３个在沛县沙土地进行造林对比试验。经５ａ系统观测,初步选出生长快、抗性强、适应性广、适宜当地推广造林的鲁刺７３０１０、鲁刺７３０６３、鲁刺７３０２９、鲁刺超１及鲁刺任堂等５个品种。     

Comparison of gene delivery methods for transformation ofRobinia pseudoacacia L. by Ti-plasmid

The binary vector plasmid pIG121-Hm carrying the chimeric neomycin phosphotransferase (npt II), β-glucuronidase (gusA) and hygromycin phosphotransferase (hpt) genes was delivered intoRobinia pseudoacacia L. callus using theAgrobacterium tumefaciens-mediated transformation method and particle gun transformation method. It was determined that adding 10 mg/L of acetosyringone toAgrobacterium infection medium and callus-Agrobacterium co-culture medium could increaseAgrobacterium-mediated transformation efficiency. In contrast, particle gun transformation could successfully deliver plasmid DNA into the callus, but its transformation efficiency was lower and gene expression was transient in comparison with theAgrobacterium-mediated method, suggesting that substantially stronger promoters might be required.     

Selection, regeneration and protein profile characteristics of NaCl-tolerant callus ofRobinia pseudoacacia L.

Changes in callus growth, differentiation potency and protein profile induced by salt stress were investigated in the calli induced from a hypocotyl ofRobinia pseudoacacia L. The NaCl treatment evidently obstructed the callus growth and the influences seemed to continue to be present in the selected calli even after they were restored in NaCl-free medium that could partially recover the callus growth, and some polypeptides were found to restore. The calli selected and restored intermittently every two weeks for one year completely lost their differentiation potency. The NaCl-tolerance test of the regenerated plantlets revealed that part of the plantlets that directly regenerated from the selected NaCl-tolerant calli were able to survive in 0.2 M NaCl, while most of the plantlets regenerated from the NaCl-nonselected calli or from restored calli were obviously damaged by this treatment. The SDS-PAGE assay indicated that a 54 kDa polypeptide increased distinctly to a very high level while a 41 kDa polypeptide decreased to a lower level in almost all the NaCl-tolerant plantlets. This observation led to the suggestion that the changes may play an adaptive role in allowing plantlets to survive under saline conditions.