生物炭对大豆根际土壤酶活性及产量的影响

研究不同生物炭施用量对大豆增产与根际土壤酶活性的影响,为大豆增产提供合理的生物炭施用量。以当地常规施肥为对照(CK),设置生物炭处理27 kg·hm^(-2)(B1)、54 kg·hm^(-2)(B2)、81 kg·hm^(-2)(B3)、108 kg·hm^(-2)(B4),生物炭与常规肥混匀沟施。结果表明:B3处理可以显著提高大豆根际土壤脲酶活性、过氧化氢酶活性以及土壤酸性磷酸酶活性;土壤β-葡萄糖苷酶活性则表现为在大豆营养生长期间B1处理酶活性最高,在生殖生长阶段B4处理酶活性最高;生物炭对土壤蔗糖酶活性的影响不显著。B3处理显著增加了大豆株高、单株荚数、有效荚数、单株粒重、百粒重及产量,各因素分别较CK增加了13.13%、32.11%、45.73%、17.41%、7.80%及7.35%。生物炭可以提高土壤酶活性、改善土壤微环境,与化肥配施可以显著增加大豆株高、有效荚数和百粒重,进而促进农作物增产增收。

间作对分蘖洋葱与番茄根际土壤磷转化强度及磷细菌群落结构的影响

【目的】间作分蘖洋葱能缓解番茄连作障碍,提高番茄养分吸收。本试验主要研究间作后分蘖洋葱和番茄根际土壤中磷细菌群落结构及活性的变化,以揭示该间作体系磷细菌改善作物磷营养的生物学机制。【方法】盆栽试验选用茄科连作8年的设施土壤,番茄品种为‘东农708’,分蘖洋葱品种为‘五常红旗社’。设番茄单作、分蘖洋葱单作、分蘖洋葱与番茄间作及无苗对照等4个处理。在定植23 d、30 d和37 d取样,测定植株干重及磷浓度。同时用抖根法取番茄和分蘖洋葱根际土,测定土壤中磷细菌数量及磷细菌的转化强度。采用PCRDGGE方法测定磷细菌的群落结构。【结果】1)间作后,番茄地上和地下干重增加,分蘖洋葱地上和地下干重减少,在37 d差异达到显著水平。2)间作后,番茄根际土壤中无机磷和有机磷细菌的数量增加,在23 d和37d差异达到显著水平;分蘖洋葱根际土壤中无机磷细菌数量在23 d时显著降低,有机磷细菌数量在间作37 d时显著升高。间作期间分蘖洋葱和番茄根际土壤中无机磷和有机磷细菌的数量均显著高于无苗对照。间作23d时,番茄根际土壤中无机磷和有机磷细菌的转化强度均显著升高,分蘖洋葱根际土壤中无机磷和有机磷细菌的转化强度均显著降低;而间作37 d时,分蘖洋葱根际土壤中无机磷和有机磷细菌的转化强度均显著升高,且间作期间番茄和分蘖洋葱根际土壤中无机磷和有机磷细菌的转化强度均显著高于无苗对照。3)间作37 d番茄和分蘖洋葱根际土壤pH显著升高,EC值显著降低,且各处理土壤pH均高于无苗对照,土壤EC值均低于无苗对照。间作30 d时番茄根际土壤中速效磷含量显著升高,间作37 d时显著低于单作。间作期间分蘖洋葱根际土壤速效磷含量变化不显著,番茄根际土壤速效磷含量均低于无苗对照,而分蘖洋葱均高于无苗对照。间作后番茄植株磷浓度和磷吸收量显著高于单作处理,分蘖洋葱植株磷浓度显著高于单作处理,而磷吸收量显著低于单作处理。4)间作后番茄根际土壤中无机磷细菌的条带数、香农多样性指数和均匀度指数显著高于其单作处理,而间作分蘖洋葱显著低于其单作处理。间作后番茄根际土壤中有机磷细菌的条带数、香农多样性指数和均匀度指数前期显著高于单作番茄,后期显著低于单作。而间作分蘖洋葱与对应单作比较差异不显著。【结论】间作分蘖洋葱通过改变番茄根际土壤中磷细菌数量和群落结构,提高了磷细菌的转化强度,增加了番茄根际土壤中速效磷含量,促进植株磷浓度和磷吸收量增加,改善了番茄磷营养。

豆饼与尿素配施对薄皮甜瓜果实酯类香味物质及关键酶的影响

以薄皮甜瓜(Cucumis melo var. makuwa Makino)果实为试材,研究了豆饼、尿素及豆饼与尿素配施对薄皮甜瓜果实酯类香气物质及关键酶的影响。结果表明,尿素处理促进了C6醇和C9醇、C6醛和C9醛物质合成,抑制了乙酸脂类和非乙酸酯类物质的合成;豆饼与尿素配施明显促进了果实中酯类物质的种类和含量的增加,尤其是提高了成熟果实中乙酸乙酯、乙酸己酯、2-甲基丁酸乙酯、异丁酸乙酯4种特征性酯类物质的含量,而豆饼处理主要是促进了非特征性酯类物质的种类和含量的增加。此外,不同处理甜瓜果实酯类物质的合成与关键酶活性变化相关,尤其是ADH和AAT活性。

Effects of abiotic stress and hormones on the expressions of five13-CmLOXs and enzyme activity in oriental melon(Cucumis melo var.makuwa Makino)

Lipoxygenases（LOXs） are a group of non-heme,iron-containing enzymes and extensively involved in plant growth and development,ripening and senescence,stress responses,biosynthesis of regulatory molecules and defense reaction.In our previous study,18 LOXs in melon genome were screened and identified,and five 13-LOX genes（CmLOX08,CmLOX10,CmLOX12,CmLOX13 and CmLOX18） were predicted to locate in chloroplast.Phylogenetic analysis result showed that the five genes have high homology with jasmonic acid（JA） biosynthesis-related LOXs from other plants.In addition,promoter analysis revealed that motifs of the five genes participate in gene expression regulated by hormones and stresses.Therefore,we analyzed the expressions of the five genes and LOX activity in leaves of four-leaf stage seedlings of oriental melon cultivar Yumeiren under abiotic stress：wounding,cold,high temperature and hydrogen peroxide（H_2O_2）,and signal molecule treatments：methyl jasmonate（MeJA）,abscisic acid（ABA） and salicylic acid（SA）.Real time qPCR revealed that wounding and H_2O_2 induced the expressions of all the five genes.Only CmLOX08 was induced by cold while only CmLOX13 was suppressed by high temperature.ABA induced the expressions of CmLOXIO and CmLOX12 while inhibited CmLOX13 and CmLOX18.MeJA increased the 3 genes expressions except CmLOX08 and CmLOX13,whereas SA decreased the effect,apart from CmLOX12.All the abiotic stresses and signal molecules treatments increased the LOX activity in leaves of oriental melon.In summary,the results suggest that the five genes have diverse functions in abiotic stress and hormone responses,and might participate in defense response.The data generated in this study will be helpful in subcellular localization and transgenic experiment to understand their precise roles in plant defense response.