一次性施入牛粪对土壤肥力和土壤微生物及酶活性的影响

为了减少农业劳动力,探讨一次性施入有机肥对丘陵地区土壤的改良效果,于2016年4月~2017年11月进行大田试验。本文以牛粪为原料,设置不同用量的牛粪处理,以常规施肥为对照,研究一次性施入牛粪对土壤肥力、微生物生物量和土壤酶活性的影响。结果表明,与常规施肥(100000 kg/hm^2)相比,一次性施入200000 kg/hm^2(T1)、300000 kg/hm^2(T2)和400000 kg/hm^2(T3)牛粪处理能显著增加20~40 cm和40~60 cm土层的土壤有机质、碱解氮、速效磷和速效钾的含量,以300000 kg/hm^2(T2)处理的效果最为显著。在5月份,300000 kg/hm^2(T2)处理的各土层有机质含量分别比CK高56.82%和108.20%,6月份,300000 kg/hm^2(T2)处理的各土层碱解氮、速效磷和速效钾的含量分别是CK的4.45倍、7.28倍、2.15倍和2.99倍、2.19倍、1.81倍;一次性施入不同用量的牛粪能显著提高各土层土壤脲酶、磷酸酶、蔗糖酶的活性,在苹果各个生长发育时期中均以300000 kg/hm^2(T2)处理的效果最佳;与CK相比,一次性施入不同用量的牛粪处理的不同土层细菌和放线菌数量显著增加,并且明显抑制了真菌的增长,以300000 kg/hm^2(T2)处理的效果最为显著。综合考虑,在丘陵地区果园管理中,以一次性施入300000 kg/hm^2牛粪处理为宜,既可以减少果园劳动力,又可提高土壤肥力,增加土壤生物活性。

混施微生物菌剂和有机肥对‘新红星’苹果解袋后果实品质的影响

以5年生‘新红星’苹果果树为试材,探究不同施肥处理(T1,有机肥;T2,微生物菌剂+有机肥;T3,微生物菌剂;CK,对照)对‘新红星’苹果解袋后果实内在品质、呼吸速率、乙烯释放率、果实硬脆性及相关酶和基因表达的影响。结果表明,与传统单一施肥相比,施加含微生物菌剂的有机肥显著提高了果实可溶性固形物含量、可溶性糖含量及糖酸比。解袋后0~12 d果实呼吸速率及乙烯释放速率显著上升,12~15 d趋于平稳。果实解袋后第9、12、15 d,T2组果实可溶性固形物含量相对于CK组高出2.63%、5.89%、8.78%;可溶性糖高出6.89%、6.71%、12.86%;糖酸比高出15.85%、19.25%、17.08%,且差异显著。施加含微生物菌剂的有机肥处理(T2)显著提高了果实的总香气含量,其含量相对于CK、T1、T3组分别高出16.69%、9.06%、6.25%。混施微生物菌剂和有机肥有利于解袋后苹果果实着色,使果皮细胞排列紧密整齐,对提升果实脆度,减缓果实硬度下降具有重要作用。细胞壁关键酶果胶甲酯酶(PME)、多聚半乳糖醛酸酶(PG)活性在解袋后一直处于上升状态,其中T2组PME、PG活性及MdPME、MdPG表达量均低于CK组,因此果实在解袋后保持较高的硬脆度。综上所述,混施微生物菌剂和有机肥(T2)对提高‘新红星’苹果果实品质及延长货架期具有重要作用。

Genome-wide analysis of the synonymous codon usage patterns in apple

Apple（Malus×domestica） has been proposed as an important woody plant and the major cultivated fruit trees in temperate regions. Apple whole genome sequencing has been completed, which provided an excellent opportunity for genome-wide analysis of the synonymous codon usage patterns. In this study, a multivariate bioinformatics analysis was performed to reveal the characteristics of synonymous codon usage and the main factors affecting codon bias in apple. The neutrality, correspondence, and correlation analyses were performed by Codon W and SPSS（Statistical Product and Service Solutions） programs, indicating that the apple genome codon usage patterns were affected by mutational pressure and selective constraint. Meanwhile, coding sequence length and the hydrophobicity of proteins could also influence the codon usage patterns. In short, codon usage pattern analysis and determination of optimal codons has laid an important theoretical basis for genetic engineering, gene prediction and molecular evolution studies in apple.

Effects of Acetylsalicylic Acid and Calcium Chloride on Photosynthetic Apparatus and Reactive Oxygen-Scavenging Enzymes in Chrysanthemum Under Low Temperature Stress with Low Light

The effects of acetylsalicylic acid （ASA）, CaCl2, and ASA ＋ CaCl2 on the photosynthetic apparatus and antioxidant enzyme activities were investigated in chrysanthemum Jinba （a cut flower cultivar） under low temperature stress with low light （TL stress） （16/12℃, day/night, PFD 100 μmol m^-2 s-1）. The results showed that under TL stress, the net photosynthesis rate （Pn）, carboxylation efficiency （CE）, apparent quantum yield （AQY）, maximal photochemical efficiency （Fv/Fm） of PSII, quantum yield of PSII electron transport （ФPSII）, and photochemical quenching （qP） of the chrysanthemum leaves in all treatments were significantly decreased, but the decreases were alleviated by ASA, CaCl2, and ASA ＋ CaCl2 treatments compared with the controls. The alleviating effect of ASA ＋ CaCI2 was better than either ASA or CaCl2 single treatment. Moreover, the ASA ＋ CaCl2 treatment highly improved the chlorophyll content, relatively improved the number and size of chloroplast and starch grain in the leaves of chrysanthemum plants compared with ASA and CaCl2 treatments. It was indicated that ASA and/or CaCI2 could regulate the photosynthetic functions in the leaves of chrysanthemum plants to enhance the resistance against TL stress. On the other hand, reduction in relative conductance rate implied that ASA and/ or CaCl2 could protect from membrane injury in leaves of chrysanthemum plants. The activities of SOD, POD, and CAT in the treated leaves of chrysanthemum were increased as compared with the controls. It was suggested that ASA and/or CaCl2 had positive regulation effects on the defence enzyme activities in chrysanthemum leaves which could protect the photosynthetic apparatus to a certain degree under the TL stress. In brief, the treatment of ASA together with CaCl2 was better for chrysanthemum plants to adapt TL stress than single ASA or CaCl2 treatments.

Dynamic Simulating to the Accumulation and Distribution of Dry Matter for Black Walnut(Juglans hindsii) Seedlings

It is very important to study eco-physiological processes of plants and to determine quantitative relations between accumulation, distribution of dry matter and environmental factors for regionalization, standardization and precision agriculture. Meanwhile, global changes, e.g., atmospheric CO2 concentration rising, global warming, and climate abnormity, have been effecting on agricultural productivity. This study provides a theoretical basis for predicting productive potentials and development trends in different agricultural regions. One-year-old black walnut （Juglans hindsii） seedlings were employed as subjects for setting up the dynamic models of dry matter accumulation and distribution, based on mechanistic models of photosynthesis, matter conservation and concentration gradient. Under optimum conditions of soil moisture and mineral nutrient, during the period of the canopy construction, the dry matter accumulation of the canopy conformed to logistic curves; but the accumulation of both total biornass and dry matter of stem-root could be divided into two phases： the first phase was exponential increase, the second was linear increase. The total biomass, dry matter of canopy and stem-root all presented a fluctuant increase, which was affected by the environmental factors. Ratio of daily increase of dry matter in the canopy and the steem-root （dWJdWs） was changeable along with growth periods and environmental factors. At the initial stage of the canopy forming, dW/dWs was larger, about 3.2 on average, which indicated that the photosynthetic product was mainly used to develop leaves; in the midterm, it was about 1.9, which indicated that the distribution of dry matter in the canopy and in the stem-root was relatively balanced; when the plant tended to stop growing, dWl/dWs decreased linearly, and the main distribution of dry matter moved to the roots.

Effect of Indole Butyric Acid on the Transportation of Stored Calcium in Malus hupehensis Rhed. Seedling

Calcium （Ca） plays an important role in the metabolism of higher plants. Recently, research on Ca^2＋ in plants has been focused especially at the cellular and molecular levels. Uptake, transport, and distribution are also very important for Ca to accomplish its function at the whole-plant level. In this experiment, one-year-old apple seedlings （M. hupehensis Rehd.） were investigated to determine the distribution of stored Ca, the different forms of Ca, and Ca^2＋-ATPase activity after treatment with indole butyric acid （IBA）. The results showed that the total Ca measured in mature leaves and Ca^2＋- ATPase activity in tender leaves were higher compared with those in the control （CK）. Calcium nitrate and calcium chloride （ALe-Ca） and calcium phosphate and calcium carbonate （HAC-Ca） decreased in both mature leaves and shoots, whereas water-soluble calcium （H2O-Ca）, calcium pectate （NaCl-Ca）, and calcium oxalate （HCl-Ca） increased. The percentage of active calcium, calcium pectate, and water-soluble calcium increased, whereas the percentage of calcium phosphate and calcium carbonate decreased. When treated with IBA, calcium fractions and percentage of the different forms of Ca was enhanced in 40 part per million （ppm） IBA compared with 20 ppm IBA and water. The results indicated that IBA increased the percentage of both active calcium （NaCl-Ca and H2O-Ca） in tender shoots and boosted the transportation of stored Ca in plants. IBA promoted Ca^2＋-ATPase activity and Ca^2＋ uptake in tender shoots of M. hupehensis. It can improve the total Ca contents and the relative percentage of Ca.