Low temperature, IBA concentrations and optimal time for adventitious rooting of Eucalyptus benthamii mini-cuttings

Eucalyptus benthamii is a forest species of economic interest that has difficulty with seed production and also is considered to have difficulty with adventitious rooting using propagation techniques,such as cutting or mini-cutting.We aimed to assess the adventitious rooting percentage under different storage times in low temperatures and at various IBA(indole-3-butyric acid) concentrations to determine the optimal time of permanence for rooting Eucalyptus benthamii minicuttings in a greenhouse.Shoots collected from mini-stumps cultivated in a semi-hydroponic system were used to obtain the mini-cuttings.For the first experiment,the mini-cuttings were stored at 4℃ for 0(immediate planting),24,48,72,96 and 120 h.The second experiment evaluated the rooting dynamic to determine the optimal time of permanence for minicuttings in a greenhouse.The basal region of the mini-cutting was treated with various IBA solutions:0(free of IBA),1,000,2,000,3,000 and 4,000 mg·L-1.Every seven days(0(immediate planting),7,14,21 and 28 days),destructive sampling of the mini-cuttings was performed to evaluate the histology of the adventitious rooting.Eucalyptus benthamii minicuttings should be rooted immediately after the collection of the shoots.The 2,000 mg·L-1 IBA concentration induced a greater speed and percentage of adventitious rooting,and an interval of 35 to 42 days was indicated for permanence of the mini-cuttings in the greenhouse.Exposure to low temperature induced adventitious root formation with diffuse vascular connections.     

Improvement of the tissue culture technique for <Emphasis Type="Italic">Melaleuca alternifolia</Emphasis>

Tea tree oil is extracted from the leaves and twigs of Melaleuca alternifolia (Maiden & Betche) Cheel, and it is widely used in medicines, food preservatives, cosmetics and health care products. Traditional propagation of M. alternifolia from seeds does not necessarily transfer the desired characteristics from their mother trees, the seedlings are not uniform, and the multiplication rate from cuttings is relatively low. For these reasons, it is necessary to develop tissue culture techniques for this species. This study showed that an efficient explant initiation medium for M. alternifolia was MS 1/2 + BA 0.6 mg L^?1 + NAA 0.1 mg L^?1 + sucrose 30 g L^?1, which yielded a 75.9 % initiation rate. An efficient multiplication medium was MS + BA 0.3 mg L^?1 + NAA 0.15 mg L^?1 + sucrose 30 g L^?1, which yielded a 4.3 multiplication rate and 3.2 cm shoot length. The rooting medium was MS 1/2 + IBA 0.1–0.25 mg L^?1 + sucrose 15 g L^?1, which yielded a 100 % rooting rate, 2.94–3.32 roots per individual and 1.36–1.44 cm root length. Local red-core soil was suitable as a transplant medium, and yielded 98 % survival. This study improved the tissue culture technique for mass-propagation of M. alternifolia, enabling the production of high quality plants for market.     

Shoot multiplication of <Emphasis Type="Italic">Syringa reticulata</Emphasis> var. <Emphasis Type="Italic">mandshurica</Emphasis> from in vitro cultured seedlings

We developed a shoot multiplication protocol for Syringa reticulata Blume var. mandshurica Hara from in vitro cultured seedlings that derived from in vitro germinated seeds. The shoots could be induced on Murashige and Skoog (MS) medium with proper plant growth regulator combinations of 6-benzylaminopurine (BA) and indole-3-butyric acid (IBA). The better medium for shoot multiplication and growth was MS + 5 mg L^?1 BA + 0.5 mg L^?1 IBA + 20 g L^?1 sucrose + 7 g L^?1 agar, and the corresponding shoot induction rate was 75 %. The plantlets grew well after rooting on 1/2MS medium (macro-elements of MS medium are at half-strength) supplemented with 1 mg L^?1 IBA, and the survival percentage was >80 % at 16 weeks after transplanting.     

Mini-cutting technique for Khaya anthotheca: selection of suitable IBA concentration and nutrient solution for its vegetative propagation

Khaya anthotheca is a hardwood species from Africa and recently introduced to Brazil. This species yields high-quality wood for diverse applications, but little has been done toward an effective propagation method for large-scale production in nurseries. We evaluated the effects of different concentrations of macro and micronutrients(i.e., 100, 50 and 25% of the concentration of a referenced solution) combined with indole-3-butyric acid(IBA) at 0 and 2 g L~(-1) on the survival rate of mini-stumps and the survival and adventitious rooting of K. anthotheca mini-cuttings. The mini-stumps were grown from a source of seeds imported from Ghana, West Africa. The ministumps survived at a high rate(97%). Consistently high shoot yields were obtained from the mini-stumps(average of 1.8 per mini-stump). High survival percentage of minicuttings and adventitious rooting were observed when solutions with 100 and 50% of the nutrients concentration were combined with 2 g L~(-1) IBA. Histological sections analyzed through optical microscopy indicated the tissues from mini-cutting stems were juvenile, which might have stimulated adventitious rooting. These results have important implications for further work aimed at establishing propagation strategies for K. anthotheca, which are of prime importance for assisting breeding programs of this species.     

<Emphasis Type="Italic">Pinus halepensis</Emphasis> somatic embryogenesis is affected by the physical and chemical conditions at the initial stages of the process

Pinus halepensis has been described as a drought-tolerant species with high plasticity to growth in different environments. Its eco-physiological characteristics could facilitate the use of this species in large afforestations in the future scenery of climate change. Somatic embryogenesis is a biotechnological tool with potential for large-scale clonal propagation. In order to establish an improved regeneration protocol for Pinus halepensis, the effects of different temperatures (18, 23, and 28 °C) and water availability conditions (2, 3, and 4 g L^?1 Gelrite^®), during initiation of embryonal masses on the rate of initiation, proliferation, maturation, and the number of embryos developed, were evaluated. It was found that environmental conditions during the initiation stage of Pinus halepensis somatic embryogenesis influence the success of initiation and proliferation. In contrast, there was no effect of these conditions on the maturation rates and the number of somatic embryos. Somatic embryos were obtained in all treatments tested, indicating that plants can be produced from extreme conditions of induction, such as high temperatures (28 °C) and low water availability conditions (4 g L^?1).     

Mini-cuttings technique: a new ex vitro method for clonal propagation of sweetgum

An efficient production system, which can quickly produce high quality plants, is shown in this study of Liquidambar styraciflua. The mini-cuttings technique was used for ex vitro clonal propagation of three sweetgum clones. The semi-hydroponics system for production of propagules was also tested, and the concentration of indole-3-butyric acid (IBA) for rooting was evaluated. Three adult clones, produced according to conventional cutting processes, were used as mini-stumps and maintained in semi-hydroponics systems of medium size sand. Ten collections of sprouts were prepared to evaluate the production of semi-hydroponics systems (mini-clonal hedges). Sprouts from collection number six were used at different concentrations of IBA solution (0; 500; 1,000; 3,000 and 6,000 mg l⁻¹) to test the mini-cuttings technique. The high survival rates of mini-stumps after ten collections (96.3%), and high annual production per square meter (~2,953 mini-cuttings) showed that the mini-clonal hedges are viable to conduct sweetgum mini-stumps. The formation of 62.5% of healthy plants after hardening under outdoor conditions showed that sweetgum could be successfully propagated by the mini-cuttings technique.     

Rooting of Prosopis alba mini-cuttings

Mesquite (Prosopis alba Grisebach), an important species in arid and semiarid regions, is currently commercially propagated by seeds and so there is great interest in developing techniques for species propagation, domestication and improvement. Cloning through mini-cuttings is a new and promising technique for the production of clonal seedlings of forest species. The main objective of this work was to evaluate vegetative propagation using the mini-cutting technique and indolebutyric acid (IBA) at different concentrations (0, 3,000, 4,500, 6,000 and 7,500 mg L^?1) on rooting of P. alba clones. Rooting was achieved in 98–100 % of the mini-cuttings at all concentrations tested. Increasing IBA concentration resulted in an increase in the number of leaves and leaflets, as well as in fresh matter weight and number and length of roots of clone seedlings, until an optimum point (between 3480 and 4800 mg L^?1) was reached. Plants were also vegetatively propagated in the field via conventional clonal garden cuttings under the same rooting conditions to compare the efficiency of the two propagation techniques. Mini-cuttings showed higher rooting and survival percentages than cuttings. A correlation analysis conducted between characteristics of stock plants (height, diameter, number of shoots) and shoots (height, diameter) showed a positive correlation between rooting and height of shoots with total root length, leaflet number, and height of clonal seedlings. We propose the mini-cutting technique as a tool for P. alba cloning.     

In vitro germination and shoot proliferation of the threatened species <Emphasis Type="Italic">Cinchona officinalis</Emphasis> L (Rubiaceae).

Cinchona officinalis (Rubiaceae) is an endemic species of the Loja Valley in southern Ecuador with medicinal uses. Because of over-exploitation in the nineteenth century and more recent disturbances to its ecosystem, C. officinalis populations are threatened. Currently, natural regeneration of the populations is low, despite its high plant regeneration and seed formation capacity. In the present study, an efficient protocol for germination, shoot proliferation and plantlets regeneration was developed for this species. Phenolic content and germination rate of C. officinalis seeds were compared with a control species, C. pubescens. Nodal segments from seedlings of C. officinalis were cultured on Gamborg medium supplemented with different combinations of plant growth regulators. Because the phenol content is high in C. officinalis, the phenolic should be removed with hydrogen peroxide or water washes to stimulate germination. Shoots and callus developed from nodal segments within 45 days using most of the tested combinations of plant growth regulators. The best rates of shoot proliferation, callus formation and adventitious buds were obtained in medium supplemented with 5.0 mg L^?1 6-benzyl-aminopurine and 3.0 mg L^?1 indole-3-butyric acid.     

Screening and verification of the factors influencing somatic embryo maturation of <Emphasis Type="Italic">Larix olgensis</Emphasis>

With embryogenic callus of Larix olgensisis, we investigated the effects of inositol, glutamine, casein hydrolysate, carbohydrate, abscisic acid and silver nitrate concentration on the maturation of the somatic embryo. Three dominant factors emerged, and we developed a response surface model based on the Box–Behnken design. We defined the optimal conditions for the maturation of somatic embryos. The contents of abscisic acid, silver nitrate, sucrose and casein hydrolysis significantly affected the amount of maturing embryos, but inositol, maltose and glutamine had no effect. By establishing a response surface model with multiple factors, we predicted that the optimal number of L. olgensis somatic embryos was 204?±?4 g^?1 on basal medium, containing 18.28 mg L^?1 abscisic acid, 5.46 mg L^?1 silver nitrate and 82.67 g L^?1 sucrose. In the verification experiments, the addition of 20 mg L^?1 abscisic acid, 5 mg L^?1 silver nitrate and 80 g L^?1 sucrose to BM yielded an average of 202.06 somatic embryos per gram. These results should guide large-scale breeding of L. olgensis.     

Insecticidal activity of thiamethoxam against the bamboo powder post beetle <Emphasis Type="Italic">Dinoderus minutus</Emphasis> Fabr. (Coleoptera: Bostrichidae)

Thiamethoxam (ACTARA^® 25WG) was evaluated for its insecticidal activities against the bamboo powder post beetle Dinoderus minutus Fabricius (Coleoptera: Bostrichidae). The study showed that thiamethoxam had contact toxicity against D. minutus. Based on dose-mortality responses, LC₅₀ values for thiamethoxam against D. minutus ranged from 1.74 to 7.94 μg ml^?1. Laboratory and field exposure tests showed that thiamethoxam at concentration of atleast 10 μg ml^?1 may have anti-oviposition or anti-feeding effects on D. minutus and can protect post harvest Bambusa vulgaris Schrad. culms against the infestation of this bamboo boring beetle.     

Direct shoot bud regeneration from shoot tip explants of <Emphasis Type="Italic">Enicostema axillare</Emphasis>: an important medicinal plant

An efficient protocol has been developed for in vitro propagation of Enicostema axillare using shoot tip explants. The shoot tip explants were cultured on MS medium supplemented with various combinations of (BAP, KIN) and (NAA/IAA & IBA) in different concentrations between 0.5 and 2.0 mg/l for multiple shoot bud induction. The highest percent of (98.51 %) was observed at 1.0 mg/l BAP in combination with 0.2 mg/l KIN while maximum number of shoot buds (8.41 shoots/explant) was noticed on MS medium containing 1.0 mg/l BAP and 0.2 mg/l KIN combination. The highest frequency (90.82 %) of multiple shoot bud regeneration was observed at 1.0 mg/l BAP and 0.5 mg/l IBA with 15.12 ± 2.12 shoots/explants. The regenerated multiple shoots were transferred to half-strength MS medium augmented with different concentration of 0.5–2.5 mg/l IBA for rooting. Among the different concentrations of IBA tested, maximum percentage of rooting (100 %) was observed in MS medium augmented with 1.5 mg/l IBA. The rooted plantlets were successfully transferred into plastic cups containing soil and sand in the ratio of 1:1. Subsequently established in the field conditions with 90 % of survival rate. The protocol developed can be utilized for both large scale plant production and conservation of germplasm of this species. The described method can be successfully employed for large-scale multiplication and in vitro conservation as well as production of secondary metabolites of E. axillare.     

Cutting propagation of <Emphasis Type="Italic">Santalum austrocaledonicum</Emphasis>: the effect of genotype,cutting source,cutting size,propagation medium,IBA and irradiance

Developing methods for routine clonal propagation of sandalwood (Santalum austrocaledonicum) is important for its domestication and development as a commercial agroforestry species. The amenability of this species to propagation by leafy stem cuttings in low-cost non-mist propagators was assessed in four separate experiments. These experiments evaluated the effects of (1) genotype (15 genotypes from two island provenances), (2) cutting position on the stock plant (apical, medial and basal), (3) cutting size (1-node/400 mm² and 2-node/800 mm² leaf area), (4) three propagation media [scoria (5 mm, air-filled porosity (AFP)—29%), vermiculite and perlite (1:1 v/v, AFP—46%) and vermiculite, perlite and peat (2:2:1 v/v/v, AFP—42%)], (5) indole-3-butyric (IBA) (3000, 4000 and 8000 ppm) and (6) irradiance in the propagator [daily light integral (DLI) 5.3, 3.9, 2.6, 2.2 mol m^?2 day^?1]. IBA, propagation media and cutting size had no significant effect on rooting percentage, root number or root growth. Evidence of provenance-based variation in rooting capacity was recorded with greater rooting success for genotypes from the island of Erromango compared with Tanna. Variation in adventitious root induction was also recorded between individual genotypes from Erromango across all four experiments. Cuttings collected from the apical and medial parts of the shoot on the stock plant had higher rooting percentage than those collected from the base. Differences in rooting capacity between apical and medial shoots were variable between experiments and may be attributed to different levels of hardening. The use of artificial shade (~?70%) to achieve a mean DLI of between 2.6 and 3.9 mol m^?2 day^?1 increased rooting percentage compared to both lower (2.2 mol m^?2 day^?1 or?~?90% shade) and higher (5.3 mol m^?2 day^?1 or?~?50% shade) irradiance treatments. Leaf retention of cuttings in the propagator was positively associated with the percentage of cuttings with adventitious roots, with highest percentage in cuttings with full leaf retention, regardless of original cutting size. This study demonstrated S. austrocaledonicum seedlings can be successfully propagated by cuttings provided the propagation conditions are optimized for each genotype.     

Litterfall,decomposition and nutrient release of <Emphasis Type="Italic">Shorea robusta</Emphasis> and <Emphasis Type="Italic">Tectona grandis</Emphasis> in a sub-tropical forest of West Bengal,Eastern India

We studied leaf litter fall, decomposition and nutrient release patterns of Shorea robusta and Tectona grandis by using a litter bag technique to better understand the release pattern of nutrients to soil from leaf litter. Annual litterfall varied from 13.40 ± 2.56 t ha^?1 a^?1 for S. robusta to 11.03 ± 3.72 t ha^?1 a^?1 for T. grandis and the decay constant (k) of decomposed leaf litter was distinctly higher for T. grandis (2.70 ± 0.50 a^?1) compared to S. robusta (2.41 ± 0.30 a^?1). Biomass loss was positively correlated with the initial litter C, WSC, C/N and ash content in S. robusta and N, P and K concentration for T. grandis. Biomass was negatively correlated with lignin and L/N ratio for S. robusta and L, WSC, L/N and C/N ratio for T. grandis (P < 0.01). Nutrient use efficiency (NUE) and nutrient accumulation index (NAI) of S. robusta was higher than for T. grandis. The retranslocation of bioelements from senescent leaves ranked as P > N > K. Annual N, P and K input to soil through litterfall differed significantly between the two species in the following order: N>K>P. S. robusta was superior in terms of K and P return and T. grandis was superior in terms of N return. The two tree species showed a similar patterns of nutrient release (K > P > N) during decomposition of their leaf litter. Nutrients of N, K and P were the primary limiting nutrients returned to soil through litterfall with important roles in soil fertility and forest productivity.     

Larvicidal,molluscicidal and nematicidal activities of essential oils and compounds from <Emphasis Type="Italic">Foeniculum vulgare</Emphasis>

Plant-based products, namely essential oils (EOs), are environmentally friendly alternatives for the control of disease vectors, hosts and/or parasites. Here, we studied the general toxicity and biopesticidal potential of EOs and phenylpropanoids from Foeniculum vulgare var. vulgare (bitter fennel), a perennial plant well adapted to temperate climates. EO/compound toxicity was tested against a freshwater snail and potential intermediate host of Fasciola hepatica (Radix peregra), a mosquito and former European malaria vector (Anopheles atroparvus) and one of the most damaging plant-parasitic nematodes, the root-knot nematode (Meloidogyne javanica). Lethal concentrations (LC₅₀; LC₉₀) of EOs (infrutescences/stems with leaves) and compounds were calculated by probit analysis. All displayed noteworthy activity against R. peregra adults (LC₅₀ 21–39 µg ml^?1) and A. atroparvus larvae (LC₅₀ 16–56 µg ml^?1). trans-Anethole revealed acute nematicidal activity after 24 and 48 h (LC₅₀ 310 and 249 µg ml^?1, respectively), and estragole (1,000 µg ml^?1) showed some effectiveness against M. javanica hatching and juveniles after 15 days. Plant and EO yields were determined to evaluate the bitter fennel productivity. The chemical composition of the EOs was analyzed by gas chromatography coupled to mass spectrometry. EOs extracted from whole plants, infrutescences and stems with leaves were characterized by estragole-dominant profiles (28–65 %), considerable amounts of phellandrene (10–34 %) and fenchone (6–16 %), and minor trans-anethole contents (1–4 %). Although additional toxicological studies against nontarget organisms are required, our study demonstrates that bitter fennel is a productive source of molluscicides and larvicides, and thus a potential sustainable biological agent to control particular host species, namely freshwater snails and mosquitoes.     

Establishment of a high-frequency regeneration system in <Emphasis Type="Italic">Cerasus humilis</Emphasis>, an important economic shrub

Cerasus humilis is a species of small, perennial, drought-resistant and multipurpose deciduous shrub grown in arid and semi-arid conditions in northern China. In this study, an efficient protocol for the rapid micropropagation of C. humilis has been standardized using stem and/or leaf explants. Direct multiple shoot induction was observed when the stem explants were cultured on Murashige and Skoog (MS) medium supplemented with different plant growth regulators. The highest shoot induction was obtained when stem explants from adult trees were cultured on MS medium supplemented with 2.0 mg L^?1 6-benzyladenine (6-BA) and 0.9 mg L^?1 α-naphthaleneacetic acid (NAA). The leaf and stem explants cultured on MS medium with 1.0 mg L^?1 6-BA and 0.6 mg L^?1 NAA, and 0.5 mg L^?1 6-BA and 0.8 mg L^?1 NAA, respectively, produced the highest induction frequency of callus. Maximum proliferation of callus was observed on MS medium containing a combination of 0.5 mg L^?1 6-BA with 0.6 mg L^?1 2,4-dichlorophenoxyacetic acid (2,4-d). Optimal shoots differentiated from callus were obtained on MS medium supplemented with 5.0mg L^?1 6-BA and 0.9 mg L^?1 NAA. In vitro rooting was achieved on half-strength (1/2) MS medium containing 0.5 mg L^?1 NAA. Rooted plantlets were hardened under control conditions and successfully acclimatized under field conditions.     

马占相思优树组培快繁技术研究*

相思(Acacia Mill.)类树种(俗称相思树)属含羞草科(Mimosaceae)金合欢属(Acacia Mill.),在我国广东、海南、广西、福建、云南和江西等地均有栽培。相思树植株高大挺拔,根系发达具根瘤,具有耐干旱贫瘠及抗风的特性,是水土保持及改良土壤的优良树种;同时,相思树还是优良的用材树种,其生     

Effect of light,fire and weed control on establishment of <Emphasis Type="Italic">Pericopsis elata</Emphasis> Harms regeneration

Pericopsis elata (a.k.a. African teak) is one of the most valuable timber species in Central Africa. Like other shade intolerant tropical tree species, P. elata could play a vital role in economic development, and ecological sustainability, but regenerates poorly following selective logging. Now endangered, there is a critical need for sustainable silvicultural systems to restore this once prominent timber species. To assess management options for P. elata we analyzed growth performance and survival in primary and secondary forest plots under burning and weeding treatments in Yoko Forest Reserve, Ubundu Democratic Republic of Congo. We transplanted nursery-grown seedlings of P. elata to experimental gaps and followed their growth and survival for 1 year. Seedlings in large canopy gaps 50 × 50 m were taller (mean difference; P = 0.006) and more likely to survive (mean difference; P < 0.001). Weeding improved both diameter (P = 0.024) and height (P = 0.007) growth rates; however, burning alone did not significantly improve the performance of P. elata seedlings. Our data suggest that P. elata regeneration is compatible with shelterwood harvesting and traditional swidden agricultural systems widely practiced in the region.     

Mating patterns of the gum arabic tree (<Emphasis Type="Italic">Acacia senegal synonym Senegalia senegal</Emphasis>) in two different habitats

Understanding the variation of mating patterns in disturbed habitats provide insight into the evolutionary potential of plant species and how they persist over time. However, this phenomenon is poorly understood in tropical dryland tree species. In the present study, we investigated how Acacia senegal reproduces in two different environmental contexts in Kenya. Open-pollinated progeny arrays of 10 maternal trees from each environmental context were genotyped using 12 nuclear microsatellite markers. Overall, A. senegal displayed a predominantly allogamous mating pattern. However, higher multilocus outcrossing rate (tm) was found in Lake Bogoria (tm = 1.00) than in Kampi ya Moto population (tm = 0.949). Higher biparental inbreeding (t _m  ? t _s  = 0.116) and correlation of outcrossed paternity (rp = 0.329) was found in Kampi ya Moto than in Lake Bogoria population (t _m  ? t _s  = 0.074, rp = 0.055), showing the occurrence of mating among relatives. Coefficient of coancestry (Θ = 0.208) showed that full-sibs constitute about 21% of the offspring in Kampi ya Moto population compared to about 14% (Θ = 0.136) in Lake Bogoria population. The results demonstrate that low adult tree density of A. senegal may be promoting seed production through consanguineous mating and suggest that man-made disturbance can affect mating patterns of the species. Despite these mating differences, trees from both populations can contribute as seed source for conservational plans, and to support effective genetic conservation and artificial regeneration programs of A. senegal. We suggest collection of seeds from at least 42 and 63 trees in Lake Bogoria and Kampi ya Moto populations, respectively, to retain a progeny array with a total effective population size of 150.     

A recommended rate for application of <Emphasis Type="Italic">Chaetomium globosum</Emphasis> ND35 fungus fertilizer on poplar plantations in China

Previous studies showed that Chaetomium globosum ND35 fungus fertilizer can improve the microbial community structure and enzyme activities of replanted soil. However, it remains unclear whether can improve the physiological and ecological characteristics of plants under successive rotation. In this study, we investigated the photosynthetic, physiological, and biochemical indexes including photosynthetic parameters, chlorophyll fluorescence, and chlorophyll content of 1-year-old poplar seedlings under seven different doses (range from 0 to 1.67 g kg^?1) of C. globosum ND35 fungus fertilizer to study the effects of fungus fertilizer on photosynthesis of Poplar. Our results showed that: (1) With increasing application of fungus fertilizer in replanted soil, chlorophyll content of poplar leaves (Chl) increased, while physiological indexes such as electron transport rate (ETR), net photosynthetic rate (P _n), quantum efficiency (Φ), nitrate reductase (NR) activity and root vigor initially increased and then declined. Meanwhile, heat dissipation that depended on the xanthophyll cycle declined and non-photochemical quenching (NPQ) initially increased and then decreased. When the dose of C. globosum ND35 fungus fertilizer was 0.67 g kg^?1 (T3) and 1.00 g kg^?1 (T4), excess light energy of photosynthetic apparatus was reduced, and photosynthetic apparatus distributed more light energy to the direction of photochemical reactions, which improved the efficiency of energy use. Plant height and biomass of leaves, stems, and roots were maximum at T3. We conclude that applying appropriate amounts of C. globosum ND35 fungus fertilizer can improve root physiological activity and capacity for use of light by poplar leaves. This can improve the operating states of the photosynthetic apparatus and lead to increased photosynthetic efficiency of poplar leaves and accumulation of dry matter. This suggests a strategy to alleviate the successive rotation obstacle of soil nutrient depletion.     

Earthworm population and microbial activity temporal dynamics in a Caspian Hyrcanian mixed forest

Few studies have analyzed how tree species within a mixed natural forest affect the dynamics of soil chemical properties and soil biological activity. This study examines seasonal changes in earthworm populations and microbial respiration under several forest species (Carpinus betulus, Ulmus minor, Pterocarya fraxinifolia, Alnus glutinosa, Populus caspica and Quercus castaneifolia) in a temperate mixed forest situated in northern Iran. Soil samplings were taken under six individual tree species (n = 5) in April, June, August and October (a total of 30 trees each month) to examine seasonal variability in soil chemical properties and soil biological activity. Earthworm density/biomass varied seasonally but not significantly between tree species. Maximum values were found in spring (10.04 m^?2/16.06 mg m^?2) and autumn (9.7 m^?2/16.98 mg m^?2) and minimum in the summer (0.43 m^?2/1.26 mg m^?2). Soil microbial respiration did not differ between tree species and showed similar temporal trends in all soils under different tree species. In contrast to earthworm activity, maximum microbial activity was measured in summer (0.44 mg CO₂–C g soil^?1 day^?1) and minimum in winter (0.24 mg CO₂–C g soil^?1 day^?1). This study shows that although tree species affected soil chemical properties (pH, organic C, total N content of mineral soils), earthworm density/biomass and microbial respiration are not affected by tree species but are controlled by tree activity and climate with strong seasonal dynamics in this temperate forest.