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1.
光合作用是衡量植物对环境响应的重要指标,通过光响应曲线拟合量化光合特征,可从生理机制方面揭示出植物在不同生长环境下自身的调节与适应机制。本文利用Li-6400便携式光合仪测定了冬小麦在4种不同处理条件下灌浆期旗叶的光响应曲线,采用直角双曲线模型(RHM)、非直角双曲线模型(NRHM)、直角双曲线修正模型(RHMM)、指数模型(EM)和指数改进模型(MEM)对光响应数据进行拟合,分析了不同CO_2浓度和土壤含水量对冬小麦光合特征的影响。结果表明,直角双曲线修正模型对各处理下冬小麦光响应曲线和光响应曲线参数的拟合值都与实测值较为接近,拟合效果最好;随着CO_2浓度升高,各水分处理下冬小麦表观量子效率(α)、光饱和点(LSP)和最大净光合速率(P_(nmax))增大,光补偿点(LCP)和暗呼吸(R_d)降低,即CO_2浓度升高能有效增加冬小麦的光能转化率和光能利用范围,提高冬小麦的光合能力;随着土壤含水量的降低,冬小麦光补偿点(LCP)和暗呼吸速率(R_d)升高,但表观量子效率(α)、光饱和点(LSP)和最大净光合速率(Pnmax)降低,即冬小麦虽然能通过提高初始光合效率抵消一部分干旱胁迫的影响,但干旱胁迫仍会降低冬小麦光合能力;此外,CO_2浓度的增加能抵消部分冬小麦因干旱胁迫引起的光合能力降低。 相似文献
2.
以黄瓜品种"博新525"(Boxin525)为试材,设置4个土壤水分处理,即正常灌溉CK(土壤相对湿度为70%~80%)、轻度胁迫T1(土壤相对湿度为60%~70%)、中度胁迫T2(土壤相对湿度为50%~60%)、重度胁迫T3(土壤相对湿度为35%~45%),利用LI-6400便携式光合仪测定不同水分处理下黄瓜叶片的光响应曲线,采用直角双曲线、非直角双曲线、指数和叶子飘等4种光响应模型对黄瓜叶片光响应过程进行模拟,运用统计方法进行模拟效果评价,以探讨水分胁迫对黄瓜叶片光响应过程的影响。结果表明:(1)水分胁迫导致黄瓜叶片净光合速率(Pn)下降,当光合有效辐射PAR(photosynthetically active radiation)为800μmol·m~(-2)·s~(-1)时,T1、T2和T3处理叶片Pn分别比CK下降17.92%、26.49%和50.00%。实测与模拟的光响应曲线对水分胁迫的响应趋势一致,随着胁迫程度增加,Pn-PAR曲线变化幅度减小。(2)水分胁迫显著影响黄瓜叶片的光响应曲线参数。4种模型模拟的叶片初始量子效率均随胁迫加重呈先升高后降低的变化趋势;叶片暗呼吸速率以T2处理最高;4种模型计算的T1、T2和T3处理叶片光饱和点平均值较CK分别下降24.28%、31.99%和38.33%,叶片最大净光合速率平均值分别降低23.88%、33.19%和55.78%。(3)CK处理的黄瓜叶片光响应曲线模拟值偏离程度及光响应曲线参数的平均相对误差均最低,水分胁迫降低了黄瓜叶片光响应曲线的模拟效果。(4)4种模型模拟效果以叶子飘模型最佳,其后依次为指数模型、非直角双曲线模型、直角双曲线模型。研究认为水分胁迫显著影响黄瓜叶片的光响应过程,降低黄瓜叶片的光合能力。 相似文献
3.
镉对不同品种水稻光合作用的影响 总被引：2，自引：0，他引：2
采用盆栽土培法,以对镉相对敏感的水稻品种YZX和相对耐受的品种XY-12为材料,通过对人工添加镉后（土壤中镉浓度达到5mg·kg-1）水稻齐穂期叶片光合速率的测定,选用直角双曲线模型、非直角双曲线模型和叶子飘新模型对光响应曲线进行拟合,探究镉对不同品种水稻叶片光响应特征的影响,并对不同光响应模型进行比较。结果表明,镉处理后,两个水稻品种净光合速率均表现为降低;镉对两水稻品种光响应曲线参数的影响存在差异,内禀量子效率、最大净光合速率、光饱和点均受到镉的影响,较不添加镉的对照降低,而镉处理后水稻剑叶光补偿点却大大增加;镉促进了品种YZX的暗呼吸作用,但对品种XY-12却表现为抑制作用;总体上,品种XY-12对土壤中镉的耐受性强于YZX;3种模型模拟的光响应曲线均能较好地反映两品种叶片光合作用的光响应特征,但光响应参数与实测值存在差异,直角双曲线模型和非直角双曲线模型拟合的最大净光合速率（Pmax）远大于实测值,并且光补偿点（LCP）和暗呼吸速率（Rd）与实测值相比存在较大差异,而采用传统的线性回归方法得到的光饱和点（LSP）却远低于实测值,叶子飘模型拟合的各项参数与实测值最为接近,并很好地弥补了其它模型的缺点。因此,该模型在反映水稻在镉毒害下叶片光合作用的光响应特征等方面具有较大优势。 相似文献
4.
为进一步探明北方地区地表臭氧（O3）浓度增加对冬小麦光合日变化、光响应能力和气体交换的影响,通过开顶式气室（OTC）,利用LI-6400便携式光合仪,开展了4种O3熏气水平下光合作用的原位测定（碳滤空气,CF;自然空气,NF;100 nL.L-1,CF100;150 nL.L-1,CF150）。结果表明,在拔节初期,4个处理组间的净光合速率Pn、气孔限制值Ls及胞间CO2浓度Ci均无显著差异。在抽穗期,CF100、CF150处理的Pn较CF降低了37.0%~41.8%,气孔导度Cond下降了35.7%~38.9%,Ci上升了6.7%~10.5%。在灌浆期,CF100的最大光合速率Pm、半饱和光强Ik较CF降低了23.5%~46.7%,暗呼吸速率Rd增加了8.6%;CF150的Pm、表观量子产额AQY和Ik较CF下降了10.4%~26.1%,光补偿点LCP和Rd增加了51.2%~88.0%。随着O3浓度和熏蒸时间的增加,冬小麦叶片的叶绿素Chl和类胡萝卜素Car含量显著降低,而可溶性糖和丙二醛MDA含量明显增加,且均在灌浆期差异最显著。以上结果表明,O3对冬小麦光合作用的抑制作用具有明显的时间累积效应,且随熏气时间的延长,叶片光合作用的限制条件由气孔因素主导向非气孔因素主导转变;同时,O3胁迫使植株对强光的耐受性及对强、弱光的利用效率均下降。 相似文献
5.
黄瓜幼苗光合作用对亚适温弱光胁迫的适应性 总被引：4，自引：1，他引：3
为探讨黄瓜光合作用对温光逆境的适应机理,研究了弱光、亚适温、亚适温弱光胁迫处理对津优3号黄瓜幼苗光合作用的影响.结果表明,弱光、亚适温、亚适温弱光胁迫均使黄瓜幼苗的光合速率(Pn)和RuBP羧化酶活性明显降低,Pn的主要限制因素是非气孔因素,但亚适温和亚适温弱光下Pn的降低与气孔限制有一定相关性.弱光和亚适温胁迫同时出现时,温度起主要作用.10 d内弱光及亚适温弱光胁迫可使黄瓜幼苗叶片的光补偿点降低.弱光和亚适温弱光处理的光下实际光化学效率(ΦPSⅡ)和初始荧光(Fo)降低,暗下光化学效率(Fv/Fm)变化不大:亚适温处理的ΦPSⅡ和Fv/Fm均降低,Fo没有明显变化.说明弱光和亚适温弱光处理没有产生明显的光抑制;亚适温胁迫诱导了黄瓜叶片PSⅡ的光抑制,但对PS Ⅱ反应中心的损伤不明显. 相似文献
6.
采用CIRAS-2便携式光合仪测定不同土壤水分条件下2年生柿树叶片净光合速率、蒸腾速率、水分利用效率、气孔导度等光合生理参数的光响应过程,探讨柿树光合光响应特性对土壤水分的响应规律。结果表明：土壤水分对柿树的光合生理参数影响显著,随着土壤水分的降低,净光合速率、表观量子效率先升后降,光补偿点先降后升,光饱和点呈下降趋势;维持柿树高光合作用和高水分利用效率的适宜土壤相对含水量为48.8%～76.7%,适宜的光照强度为800～2 000μmol/（m2·s）;柿树对强光利用能力较强,而对弱光的利用效率较低;在土壤相对含水量为48.8%时,柿树光合作用主要受气孔限制,而土壤相对含水量降低到25.5%时,柿树光合作用转变为非气孔限制,通过对气孔、非气孔因素的判定,可知柿树是一种抗旱性非常强的植物。研究结果可为柿树的节水高产栽培提供理论依据。 相似文献
7.
春大豆生长中对不同氮源的吸收利用 总被引：7，自引：3，他引：4
利用15N示踪技术和框栽方法,对大豆不同生育期(苗期V4,初花期R1,盛花期R2,结荚初期R4,鼓粒期R5,成熟期R6,收获期R8)各部位及全株氮素来源进行系统的研究。结果表明,在大豆生育前期土壤氮和肥料氮是根、茎、叶片氮素的主要来源,在生育后期根瘤固氮开始增加;随生长大豆荚果氮素中土壤氮所占比例逐渐减小,根瘤固氮所占比例逐渐增加,并在收获期(R8)达到总量的70.6%,肥料氮所占比例一直很低。苗期至初花期(V4~R1)是无机氮营养期,大豆主要依靠土壤氮和肥料氮;初花期至鼓粒期(R1~R5)是无机氮营养与根瘤固氮并行期,既依靠土壤氮和肥料氮,又有根瘤固氮的供应;鼓粒期至收获期(R5~R8)是根瘤固氮营养期,主要依靠根瘤固氮。 相似文献
8.
生殖生长期弱光对番茄表型特征和果实品质的影响 总被引：1，自引：0，他引：1
在人工光型植物工厂中以番茄品种“丰收74-560 RZ F1”为试材,分别在花期、果实膨大期、转色期、采收期进行160μmol·m−2·s−1的弱光处理,非处理的生殖生长期光强度均保持在1000μmol·m−2·s−1,通过番茄生长和果实品质指标评估不同生殖生长期弱光对番茄的影响。结果表明：（1）花期或膨大期弱光处理对番茄植株形态结构影响较大,其中花期弱光处理下的番茄植株徒长趋势最突出,且平均单株叶片数和节数最少,较对照分别减少了3.5个和1.6个;膨大期弱光处理后番茄叶片叶绿素a/b值及类胡萝卜素含量较其他处理显著降低;花期弱光处理后单株第一果穗坐果数较对照降低了53%,其他发育期弱光处理后坐果数均未受到显著影响;花期或膨大期弱光处理后平均单株第一、二、三果穗产量均显著低于其他发育期弱光处理;（2）与对照相比,各发育期弱光处理导致番茄第一穗果实可溶性固形物含量均出现不同程度的降低,其中花期降低25%,转色期弱光处理后番茄果实可溶性糖含量较对照降低15%,但总酸含量提高了26%,导致该处理下番茄果实糖酸比最低;与对照相比,所有发育期弱光处理后果实维生素C含量均有所降低,以采收期弱光处理后番茄果实维生素C含量最低。研究表明弱光导致番茄产量和品质降低,且不同生殖阶段番茄对弱光的敏感性有所差异。根据不同时期番茄生长特性及其对弱光的响应特点进行针对性补光对设施番茄稳质稳产具有一定的意义。 相似文献
9.
遮荫对水稻冠层叶片SPAD值及光合、 形态特性参数的影响 总被引：6，自引：0，他引：6
SPAD（soil-plant analysis and development）计是一种快速、 方便、 非破坏性的诊断植物叶片相对叶绿素或氮含量的仪器,与传统的氮营养诊断方法相比,此仪器节省时间、 劳力和资源。本试验通过未遮荫和遮荫的方法观察水稻冠层叶片SPAD值、 叶绿素含量、 叶绿素荧光、 光合参数、 叶片厚度和比叶重（叶片干重除以叶片的面积）等生理形态指标的变化,建立SPAD值与光系统II（PSII）最大量子产量（Fv/Fm）之间的回归关系。结果表明,遮荫条件下,甬优9号(YY9)和丙9363(B9363)冠层叶片变薄、 SPAD值、 叶绿素a/b、 比叶重、 电子传递速率（ETR）降低,但快速光曲线的初始斜率无明显变化; 同时, 遮荫导致了叶片的呼吸速率、 最大净光合(Pmax)、 量子效率、 光补偿点和饱和点降低,表明水稻叶片为适应弱光环境, 降低光合能力、 减少呼吸消耗, 以增加对有限光能的利用。不同光照条件下,水稻冠层叶片SPAD值与PSII的Fv/Fm的回归方程呈指数式关系（YY9 R2=0.896; B9363 R2=0.833）, 表明SPAD计可以快速、 无损、 有效地评估水稻冠层叶片的光合作用进程,当SPAD值小于35时,其光合过程可能处于受损状态。 相似文献
10.
在黄土高寒区,通过人工控制土壤水分的方法,利用Li-6400便携式光合测定系统对银水牛果和沙棘苗木叶片的气体交换参数因子的光响应进行研究。结果表明,2种灌木的净光合速率、蒸腾速率、水分利用效率随着光强的增大而增强,而随着光强进一步增大,净光合速率、水分利用效率却出现下降的趋势,蒸腾速率仍继续增大。随着土壤含水量的增加,2种灌木的净光合速率、蒸腾速率、气孔导度、胞间CO2浓度逐渐增大,水分利用效率先上升,在轻度水分胁迫下达到最大值后下降。在相同土壤含水量下,银水牛果光补偿点明显小于沙棘,光饱和点大于沙棘,光能利用率高于沙棘;银水牛果的表观量子效率大于沙棘,在低光强下的光合能力较高。在水分胁迫下,2种灌木相比,沙棘比银水牛果更易受强光胁迫;银水牛果对弱光的利用能力高于沙棘,水分利用效率高于沙棘,耐旱生产力较高。 相似文献
11.
The effects of phosphorus supply (0, 30, and 90 mg P kg‐1) on growth, N2 fixation, and soil N uptake by soybean (Glycine max (L.) Merr.) were studied in a pot experiment using the 15N isotope technique. Phosphorus supply increased the top dry matter production at flowering and the dry matter production of seeds, straw, pod shells, and roots at late pod filling of inoculated soybeans. Phosphorus supply reduced the N concentration of plant tops at flowering, but increased the amount of N accumulated at both flowering and late pod filling. In inoculated soybeans total N accumulation paralleled the dry matter production. The P concentration in above‐ground plant parts of nodulated soybeans was not affected by P application. At flowering only 18 to 34% of total N was derived from N2 fixation, whereas as much as 74% was derived from N2 fixation at late pod filling. Only the addition of 90 mg P kg‐1 soil significantly increased the amount of N2 fixed at the late pod filling stage. Phosphorus supply did not influence the uptake of fertilizer or soil N in soybeans, even if the root mass was increased up to 60% by the P supply. 相似文献
12.
Seasonal critical concentration and relationships of leaf phosphorus and potassium status with biomass and yield traits of soybean
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下载免费PDF全文 Analysis of uppermost fully expanded leaves is useful to detect a deficiency of mineral nutrients such as phosphorus (P) and potassium (K) in soybean. Although, the leaf P or K status aids in fertilizer management, information on nutrient seasonal relationships with growth and yield traits at maturity are limited. To investigate this, soybean was grown under varying P or K nutrition under ambient and elevated CO2 concentrations. Results show significant relationships of the relative total biomass and yield‐related traits with the foliar P and K concentrations measured several times in the season across CO2 levels. However, the relationships established earlier in the season showed that the growth period between 25 and 37 d after planting (DAP), representing the beginning of flowering and pod, respectively, is the best for leaf sampling to determine the foliar P or K status. The leaf P and K status as well as the critical leaf P (CLPC) and K (CLKC) concentrations for traits such as seed yield peaked around 30 DAP (R2 stage) and tended to decline thereafter with the plant age. The CLPC and CLKC of seed yield indicate that the leaf P and K concentration of at least 2.74 mg g?1 and 19.06 mg g?1, respectively, in the uppermost fully expanded leaves are needed between 25 and 37 DAP for near‐optimum soybean yield. Moreover, the greatest impact of P and K deficiency occurred for the traits that contribute the most to the soybean yield (e.g., relative total biomass, seed yield, pod and seed numbers), while traits such as seed number per pod, seed size, and shelling percentages were the least affected and showed smaller leaf critical concentration. The CLPC or CLKC for biomass and seed yield was greater under elevated CO2 24–25 DAP but varied thereafter. These results are useful to researchers and farmers to understand the dynamics of the relationship of pre‐harvest leaf P and K status with soybean productivity at maturity, and in the determination of suitable growth stage to collect leaf samples. 相似文献
13.
An experiment was conducted to identify the main nitrogenous compound transported in the xylem sap of soybean plants nodulated with Rhizobium fredii. Soybean (Glycine max L. Merr.) cultivars, wild type Bragg (nod+, fix+) and its nitrate tolerant, hypernodulating mutant ntsll16 (nod++, fix+) were used for this experiment. These soybean plants were inoculated with a slowgrowing rhizobium, Bradyrhizobium japonicum USDAllO or fast-growing rhizobia consisting of a mixture of R. fredii USDA191, USDA193, and USDA-194 and grown in a phytotron under natural light and controlled temperature conditions. Xylem sap was collected from Bragg and ntsll16 plants at the flowering and pod elongation stages. Acetylene reduction activity per plant or per nodule weight was not different between soybean lines and inoculums. The composition of the nitrogenous compounds in the xylem sap was compared between the symbionts, with B. japonicum and R. fredii. At the flowering stage, ureide-N and amide-N accounted for 53 to 70% and 20 to 27% respectively of the total N in the sap collected from the plants inoculated either with B. japonicum or R. fredii. At the pod elongation stage, ureide-N and amide-N accounted for 74 to 85%, and 7 to 19% of total sap N. With the growth of the soybean plants, the ratio of ureide-N in the xylem sap increased. These results suggest that in the case of wild soybean and the hypernodulating mutant line nodulated by R. fredii, ureide is transported as the main nitrogenous compound of fixed nitrogen in the xylem sap in the same way as in plants nodulated with B. japonicum. 相似文献
14.
High concentrations of Se in soil might have negative effects on microorganisms. For this reason, the effect of organic substrate
addition (glucose + maize straw) on Se volatilisation in relation to changes in microbial biomass and activity indices was
investigated using an artificially Se-contaminated soil. Microbial biomass N was reduced on average by more than 50% after
substrate addition, but adenylate energy charge (AEC) and metabolic quotient qCO2 were both increased. The Se content decreased by nearly 30% only with the addition of the organic substrate at 25°C. No significant
Se loss occurred without substrate at 25°C or with substrate at 5°C. In the two treatments with substrate addition, the substrate-derived
CO2 evolution was about 30% lower with Se addition than without. In contrast, Se had no effect on any of the other soil microbial
indices analysed, i.e. microbial biomass C, microbial biomass N, adenosine triphosphate (ATP), AEC, ATP-to-microbial biomass
C, and qCO2. 相似文献
15.
In this study, the effects of growing maize plants on the microbial decomposition of easily degradable plant residues were
investigated in a 90-day pot experiment using a sandy arable soil. Four treatments were carried out: (1) untreated control,
(2) with freshly chopped alfalfa residues (Medicago sativa L.) incorporated into soil, (3) with growing maize plants (Zea mays L.), and (4) with growing maize plants and freshly chopped alfalfa residues incorporated into soil. The amount of alfalfa
residues was equivalent to 1.5 mg C g−1 soil and 120 μg N g−1 soil. At the end of the experiment, only the combination of growing maize plants and alfalfa residues significantly increased
the contents of microbial biomass C, microbial biomass N, and ergosterol in soil compared to the non-amended control. The
dry weight of the maize shoot material was more than doubled in the treatment with alfalfa residues than without. In treatment
(2), 6% of the alfalfa residues could be recovered as plant remains >2 mm. In treatment (4), this fraction contained 14.7%
alfalfa residues and 85.3% maize root remains, calculated on the basis of δ
13C values. This means that 60% more alfalfa-C was recovered than in treatment (2). The reasons for the retardation in the breakdown
of alfalfa residues might be water deficiency of soil microorganisms in the increased presence of maize roots. Assuming that
the addition of alfalfa residues did not affect the decomposition of native soil organic matter, only 23% of the alfalfa residues
were found as CO2 monitored with a portable gas analyzer with a dynamic chamber. The discrepancy is probably due to problems in measuring peak
concentrations of CO2 evolution in the two alfalfa treatments at the beginning of the experiment and in the two maize treatments at the end, especially
in treatment (4). 相似文献
16.
玉米/大豆套作可显著提高粮食产量和养分利用效率。研究间套作作物根茬分解、养分释放规律及其对土壤生物学特性的影响,对阐释该系统中作物养分高效利用具有重要意义。本研究采用室内培养方式,控制根茬总量为2%(2 g根茬+98 g土壤),分别设置单独的大豆根茬(S)和玉米根茬(M)及两种根茬按3∶1、1∶1和1∶3混合(分别表示为SM 3∶1、SM 1∶1和SM 1∶3)共5个不同根茬配比处理和1个不加根茬处理(CK),动态测定根茬矿化速率,碳、氮含量和土壤微生物量碳等指标。研究结果表明:培养前9 d,根茬矿化速率最快,而后矿化速率逐渐降低,到培养60 d后所有处理根茬矿化速率趋于稳定。整个培养周期内玉米根茬CO_2累积释放量显著高于大豆根茬处理,但SM 1∶3处理的CO_2累积释放量始终高于其他处理。培养结束后,SM 1∶3处理的有机碳矿化量显著高于其他处理。根茬总碳含量在前10 d无显著变化,10~60 d时显著降低,后趋于平稳。培养结束后SM 1∶3处理的根茬碳含量相比初始值降低最多,降幅达到24.8%,其次是玉米根茬(M)处理,降幅为21.4%,大豆根茬(S)处理碳含量降低最少,为9.7%。根茬总氮含量在前10 d显著降低,10~100 d总氮含量显著增加。培养结束后大豆根茬(S)总氮含量最高,SM 1∶3处理总氮含量最低。土壤微生物量碳含量在培养周期内呈先增加后降低而后趋于平稳的变化规律。培养结束后与CK相比,SM 1∶3、SM 1∶1、M、S和SM 3∶1处理的土壤微生物量碳含量分别增加89.4%、58.8%、47.1%、41.2%和37.5%。因此,玉米、大豆根茬混合后在土壤中的矿化速率、养分释放速率明显高于单一根茬处理,且有利于土壤微生物的繁殖。在本试验所选的3种配比中,SM 1∶3的配置效果最佳。 相似文献
17.
大豆生长期间的土壤呼吸 总被引：5，自引：0，他引：5
Soil respiration induced by soybean cultivation over its entire growing season and the factors influencing soil respiration were investigated to examine the seasonal pattern of soil respiration induced by soybean cultivation, explore soybean growth and photosynthesis on soil respiration, and determine the temperature dependence on soil respiration. Soil respiration in a pot experiment with and without soybean plants was sampled using the static chamber method and measured using gas chromatograph. Air temperature was a dominant factor controlling soil respiration rate in unplanted soil. Additionally, rhizosphere respiration comprised 62% to 98% of the soil respiration rate in the soybean-planted soil varying with the soybean growth stages. Harvesting aerial parts of soybean plant caused an immediate drop in the soil respiration rate at that stage. After harvesting the aerial parts of the soybean plant, a highly significant correlation between soil respiration rate and air temperature was found at the flowering stage （P 〈 0.01）, the pod stage （P 〈 0.01）, and the seed-filling stage （P 〈 0.05）. Thus, rhizosphere respiration during the soybean-growing period not only made a great contribution to soil respiration, but also determined the seasonal variation pattern of the soll respiration rate. 相似文献
18.
《Soil Science and Plant Nutrition》2013,59(2):198-205
Abstract We studied the effect of crop residues with various C:N ratios on N2O emissions from soil. We set up five experimental plots with four types of crop residues, onion leaf (OL), soybean stem and leaf (SSL), rice straw (RS) and wheat straw (WS), and no residue (NR) on Gray Lowland soil in Mikasa, Hokkaido, Japan. The C:N ratios of these crop residues were 11.6, 14.5, 62.3, and 110, respectively. Based on the results of a questionnaire survey of farmer practices, we determined appropriate application rates: 108, 168, 110, 141 and 0 g C m?2 and 9.3, 11.6, 1.76, 1.28 and 0 g N m?2, respectively. We measured N2O, CO2 and NO fluxes using a closed chamber method. At the same time, we measured soil temperature at a depth of 5 cm, water-filled pore space (WFPS), and the concentrations of soil NH+ 4-N, NO? 3-N and water-soluble organic carbon (WSOC). Significant peaks of N2O and CO2 emissions came from OL and SSL just after application, but there were no emissions from RS, WS or NR. There was a significant relationship between N2O and CO2 emissions in each treatment except WS, and correlations between CO2 flux and temperature in RS, soil NH+ 4-N and N2O flux in SSL and NR, soil NH+ 4-N and CO2 flux in SSL, and WSOC and CO2 flux in WS. The ratio of N2O-N/NO-N increased to approximately 100 in OL and SSL as N2O emissions increased. Cumulative N2O and CO2 emissions increased as the C:N ratio decreased, but not significantly. The ratio of N2O emission to applied N ranged from ?0.43% to 0.86%, and was significantly correlated with C:N ratio (y = ?0.59 ln [x] + 2.30, r 2 = 0.99, P < 0.01). The ratio of CO2 emissions to applied C ranged from ?5.8% to 45% and was also correlated with C:N ratio, but not significantly (r 2 = 0.78, P = 0.11). 相似文献
19.
选取晋西黄土区典型的苹果(Malus pumila)-大豆(Glycine max)间作系统为研究对象,在大豆的关键物候期对间作系统和对照单作的土壤水分、大豆生长状况和产量进行了定位监测。研究结果表明:(1)不同物候期,间作系统土壤平均含水量变化显著,苹果树和大豆对土壤水分竞争的空间区域和强度也有明显差异,土壤水分耗用最大的时期为大豆开花期;(2)水平方向上,各个物候期间作系统土壤含水量均随着与树行距离的增加而增加,最低值出现在距离果树行最近的区域;(3)垂直方向上,在大豆的苗期和结荚期间作系统土壤含水量随土壤深度的增加而递增,在开花期,土壤含水量随着土壤深度的增加出现先减小后增加的趋势;(4)当前树龄下,苹果-大豆间作系统的水分效应相对于大豆单作,整体表现为负效应,并对间作大豆的生物量和产量有着一定的负面影响。基于苹果-大豆间作系统土壤水分在不同物候期的分布特征,建议采取适当的管理措施以缓解种间水分竞争并提高大豆的产量。 相似文献
20.
以转甜菜碱醛脱氢酶(betaine aldehyde dehydrogenase)基因(BADH)大豆、非转基因亲本‘黑农35’、野生大豆、当地栽培种‘抗线王’、耐盐碱性较差品种‘合丰50’等5种大豆品种为材料,在典型盐碱土封闭种植,于大豆苗期、花荚期、鼓粒期和成熟期取根际土,采用经典方法测定氮素转化过程相关的细菌数量、生化功能及速效氮含量等指标的动态变化,为揭示转BADH基因大豆对土壤氮素转化的影响机制提供理论支持。结果表明:与非转基因亲本相比,转BADH基因大豆对苗期和花荚期根际土壤固氮菌数量有促进作用,但抑制苗期和花荚期根际土壤氨化细菌数量,对硝化细菌数量无显著性影响;显著促进成熟期大豆根际土壤固氮作用强度,对大豆苗期、花荚期和鼓粒期根际土壤氨化作用强度有显著抑制作用,显著促进各生育时期硝化作用强度;转BADH基因大豆苗期和花荚期根际土壤铵态氮含量显著降低,对鼓粒期根际土壤铵态氮含量无显著性影响,成熟期根际土壤铵态氮含量显著增高,大豆苗期、鼓粒期和成熟期根际土壤硝态氮含量显著升高,花荚期根际硝态氮含量显著降低。研究结果说明,转BADH基因大豆通过调节苗期、花期根际土壤氮素转化功能菌数量和生化过程强度进而影响氮素转化。 相似文献