[Effects of dazomet fumigation on growth, biological characteristics of Malus hupehensis seedlings and soil environment]. / 棉隆熏蒸处理对平邑甜茶幼苗生长和生物学特性及土壤环境的影响.

In this study, we examined the effects of dazomet fumigation with different concentrations (0, 0.1, 0.2, 0.4 g·kg-1) on the microbial characteristics of continuous cropping soil and growth of Malus hupehensis seedling in greenhouse and open-field pot. The results showed that all the treatment of dazomet fumigation could promote the growth of M. hupehensis seedlings in continuous cropping soil, with 0.2 g·kg-1 treatment showing the strongest effect. Compared to the control, plant height, stem diameter, dry weight of M. hupehensis seedlings in 0.2 g·kg-1 dazomet fumigation were increased by 192.9% and 91.8%, 72.8% and 60.1%, 196.8% and 195.0%, 138.5% and 130.7%, respectively in greenhouse and open-field. The root related indices (root length, root area, root volume, root respiration rate) were significantly promoted. The activities of SOD, POD, CAT in roots were increased by 114.6% and 118.5%, 123.5% and 107.6%, 164.6% and 175.6% respectively compared with the control, whereas the content of malondialdehyde was significantly lowered. Soil bacterial content, fungal content, copy number of Fusarium oxysporum gene and soil enzyme activity were significantly decreased with the increasing dazomet concentrations. In conclusion, 0.2 g·kg-1 dazomet fumigation could increase the biomass of M. hupehensis seedlings in continuous cropping, improve soil environment, and effectively alleviate the continuous cropping obstacle. Therefore, 0.2 g ·kg-1 dazomet fumigation could be given priority during the reconstruction of old apple orchards.

[Effects of residual apple fermentation products on continuous cropping soil environment and the growth of Malus hupehensis Rehd. Seedlings]. / æ®‹æ¬¡è‹¹æžœå‘é µäº§ç‰©å¯¹è¿žä½œåœŸå£¤çŽ¯å¢ƒåŠ'平邑甜茶'幼苗生长的影响.

Effects of fermented apple products on the growth of continuous cropping Malus hupehensis Rehd. seedlings and soil environment were examined in a pot experiment to provide theoretical basis for apple replant disease. There were four treatments, the replanted soil (control, CK), sterilized replant soil (T1), replanted soil applied with apple fermentation products (T2), and replanted soil applied with sterilized apple fermentation products (T3). The results showed that T1, T2 and T3 significantly promoted seedlings growth, with better performance of T1 and T2. T1 increased root respiration rate, plant height, ground diameter, fresh weight, and dry weight by 107.3%, 50.6%, 42.4%, 171.7%, 225.3%, while T3 increased them by 104.4%, 50.6%, 42.3%, 171.8%, 225.5%, respectively over CK. T2 and T3 increased the activities of nutrient conversion-related enzymes in continuous cropping soil. T2 increased the activities of catalase, urease, neutral phosphatase and sucrase by 44.5%, 169.5%, 23.4%, 169.3%, while T3 increased them by 23.7%, 72.6%, 1.5%, 121.5%, respectively. Catalase and sucrase activities under T1 treatment did not differ from that in CK, whereas their urease and neutral phosphatase activities were reduced by 40.8% and 41.6%, respectively. The contents of ammonium, nitrate, available phosphorus and available potassium in T2 soil were increased by 18.6%, 50.6%, 14.0% and 36.7% respectively. T3 only increased the content of available nitrogen, with ammonium and nitrate being increased by 7.0% and 23.6% respectively. The content of available nutrients of T1 decreased compared with CK. T1 and T2 significantly reduced the abundance of actinomycetes and fungi in soil and increased that of bacteria. The abundance of bacteria, actinomycetes and fungi in T3 treatment were all significantly decreased. Results of real-time fluorescence quantitative PCR analysis showed that the gene copies of Fusarium proliferaturn, F. moniliforme, F. solani and F. oxysporum in T1, T2 and T3 were ecreased to different degrees. Apple fermented product could inhibit soil pathogen in replanted orchard soil, improve soil environment, and promote seedling growth, which could be used to alleviate the apple replant disease.

Effects of antagonistic bacteria B6 against the pathogens of apple replant disease on the biomass of Malus hupehensis Rehd seedlings and soil environment under replanting.

We isolated strains from the rhizosphere soil of apple trees with replanting disease and evaluated the biological control potential for the pathogens Fusarium proliferatum, F. moniliforme, F. oxysporum, and F. solani. The morphological, physiological and biochemical character, and 16S rDNA sequence of the strain with the highest inhibitory rate were analyzed. The effect of strain biofertilizer on the biomass of Malus hupehensis Rehd. seedlings and soil environment under replanting disease was evaluated in a pot experiment. The results showed that the strain B6 had the strongest antagonistic activity. The inhibitory rate of B6 for F. proliferatum, F. moniliforme, F. oxysporum, Fusarium solani reached 71.8%, 70.1%, 72.6% and 91.5%, respectively. The strain B6 was identified as Bacillus methylotrophicus according to the results of morphological, physiological and biochemical character and 16S rDNA sequence analysis. Compared with the control, the bacterial manure made from the strain B6 enhanced the biomass of Malus hupehensis Rehd. seedlings in replanting soil to different extent. The ground diameter, fresh and dry mass were significantly increased by 18.3%, 49.6% and 51.2%, respectively. The strain B6 dramatically increased the number of cultivable bacteria and actinomyces in replanting soil and reduced the abundance of fungus to 37.7%, which accelerated the conversion of fungal soil to bacterial soil. It also dramatically increased the activities of sucrase, phosphatase, ureaseandcatalase in soil by 37.3%, 24.0%, 42.9% and 49.4%, respectively. In conclusion, the B6 fertilizer could improve the structure of cultivable microbial communities in the continuous cropping soil of apple trees, increase the soil enzyme activity, and enhance the growth of Malus hupehensis seedlings.

Screening of bacteria that antagonize the main pathogen fungi of apple replantation disorders from anaerobic fermented fluid of organic material and its inhibitory effect.

Anaerobic fermented organic materials fluid (AFOF) could alleviate apple replant diseases. In this study, bacteria from AFOF was screened which could antagonize the main pathogenic fungi (Fusarium solani, F. proliferatum, F. oxysporum, F. moniliforme). The effects of the antagonistic bacteria were verified by pot experiment. The results showed that AFOF could significantly inhibit the pathogenic fungi growth and reproduction. Four strains (L11, L12, L13, L14) with strong inhibition activity were obtained from AFOF by the confrontation test, with the highest inhibitory rate being up to 57.3%. All the four strains were Bacillus, with no obvious antagonism each other. Both antagonistic bacteria and methyl bromide fumigation could promote the biomass of Malus hupenhensis seedling compared with continuous cropping soil. Methyl bromide fumigation led to the best growth of M. hupenhensis seedling. The antagonistic bacteria cloud improve root activity, with root length and root tip number increased by 25.1% and 70.9%, respectively. Compared with the continuous cropping soil, antagonistic bacteria and methyl bromide fumigation effectively decreased soil fungi by 71.2% and 64.2%, respectively. Treatment with antagonistic bacteria increased soil bacteria and soil actinomycetes by 48.0% and 140.2%, respectively, indicating that soil microbial community was transformed to "bacteriatype". Treatment with methyl bromide fumigation could significantly reduce soil bacteria and soil actinomycetes, suggesting the antagonistic bacteria could inhibit the growth of pathogenic fungi in soil.

[Research progress of cover crop in Chinese orchard].

Grass growing in orchard is implemented in most fruit cultivation advanced countries, but only China carries out grass weeding. To effectively resolve the puzzle on harmful or beneficial effect on fruit production imparted by grass growing, and promote grass growing management in orchard in China, more and more domestic research was reported in recent years. Combined the results of our research and domestic related research, we reviewed the latest research progress about the effect of growing grass on soil, microclimate, fruit tree diseases and insect pests, tree growth and fruit quali- ty, etc. in this paper. We pointed out that grass growing in orchard must consider the local conditions, economic efficiency, the critical period, and the supporting technique.

[Effects of waterlogging on root respiration intensity and respiratory enzyme activities of sweet cherry].

Taking Meizao/Dongbeishanyingtao (Prunus serrulata G. Don) and Meizao/Mahaleb (P. mahaleb L.) as test materials, the respiration intensity and respiratory enzyme activities of their growing roots and brown lignified roots were determined under waterlogging. The results showed that under waterlogging, the root respiration intensity of the two kind rootstocks had a decreasing trend, with more decrement for their growing roots. For P. serrulata, the decrement of the respiration intensity of its growing roots and brown lignified roots was 1.47 and 1.36 times as much as that of P. mahaleb, respectively. The pyruvate decarboxylase (PDC) and lactate dehydrogenase (LDH) activities of the two kind roots had a decrease after an initial increase. Alcohol dehydrogenase (ADH) activity in growing roots also had a decrease after an initial increase, but that in brown lignified roots had an increasing trend. The test three enzyme activities changed more in growing roots than in brown lignified roots. The increment of ADH and LDH activities was higher for P. serrulata than for P. mahaleb, while PDC activity was in adverse. The malate dehydrogenase (MDH) activity of the two kind roots decreased, and the decrement was larger in growing roots than in brown lignified roots. P. serrulata had a larger decrement of root MDH activity than P. mahaleb To the waterlogging stress, growing roots was more sensitive than brown lignified roots, and P. serrulata was more sensitive than P. mahaleb.

[Changes in glycosidases and cellulase activities, and cell wall composition in strawberry fruits during development and ripening].

Experiments were carried out with two strawberry (Fragaria x nanassa Duch.) cultivars Fengxiang and Hongfeng, with different softening characteristics during growth, ripening and postharvest storage. The fruits were harvested at different stages of growth and ripening, as assessed by size and the coloration of the surface of the fruits. We selected the following stages: small and green (S1), large and green (S2), white (S3), reddish (S4), and fully red (S5). The main results were as follows. Both alpha- and beta-galactosidase activities were changed with ripening of strawberry fruits (Fig.1A, B). Of the strawberry cultivars tested, no correlation was found between glucosidase activity and fruit ripening (Fig.1C, D). Alpha-mannosidase is an enzyme being ionically bound with cell wall and its activities is correlated with the softening of strawberry fruits (Fig.1E, F). No beta-mannosidase has been detected in strawberry. The activities of cellulase increased as the strawberry fruits developed from stage of small and green to stage of overripe (Fig.2A). The activities of PME increased during the development of strawberry fruits (Fig.2B). Endo-PG was not detected in strawberry, and exo-PG was not related to fruit ripening (Fig.2C). Changes in cell wall component contents were clearly related to the changes in the firmness of strawberry fruits. The increase in soluble pectin, together with reduction of ionically bound pectin content, covalently bound pectin content (Fig.3A, B) and cellulose (Fig.3A, B) resulted in softening of strawberry fruits.