龙须菜(Gracilaria lemaneiformis)的生长、光合作用及其对扇贝排泄氮磷的吸收

研究了不同温度、光照条件下大型藻类龙须菜(Gracilaria lemaneiformis)的生长和光合作用特性,及其对扇贝排泄氮、磷的吸收作用。结果表明温度与龙须菜的生长和光合作用显著相关,在本实验条件下,15~25℃都适宜龙须菜生长,其中20℃龙须菜具有较高的生长率(SGR),为2·8%/d;光合作用速率随温度升高和光照的增加而升高,30℃和120μmol/(m2·s)时最高,最大光合作用速率(Pmax)为5·0mg O2/(g dw·h)。龙须菜对扇贝排泄氮、磷有较强的吸收作用,其吸收率和去除效率与放养密度和养殖时间有关。对NH4-N和PO4-P的最大去除效率分别为83·7%和70·4%,最大吸收率分别为9·9μmol/(g ww·h)和4·3μmol/(g ww·h)。实验证明龙须菜生长温度范围和光照范围适合中国北方海区养殖,并且能有效吸收和去除扇贝排泄氮、磷,可以作为生物滤器与贝类及其他养殖动物进行综合养殖。     

秸秆焚烧对土壤有机质和氮磷钾含量的影响

秸秆露天焚烧作为对废弃秸秆常见的处理方式在中国普遍存在。目前的研究多集中在焚烧对区域大气环境的影响,对土壤环境的化学效应研究较少。因此,为揭示大田秸秆焚烧对土壤生物化学性质的影响,设置不焚烧(CK)、减量焚烧(A1)、全量焚烧(A2)、增量焚烧(A3)4个处理,通过连续4个月的田间小区定位试验,探究不同小麦秸秆焚烧量对耕层0—5 cm土壤有机质含量、微生物数量、土壤养分含量的即时效应和各指标在玉米各生育期内的变化情况。结果表明:小麦秸秆焚烧1 d后土壤有机质含量和微生物数量相对于CK显著降低(P0.05)。其中,有机质含量在焚烧后减少11.0%—22.1%,真菌数量降低30.8%—56.1%,细菌数量降低50.6%—72.6%,放线菌数量降低46.9%—68.3%。土壤全效和速效养分含量显著增加(P0.05):全磷含量增加6.5%—12.9%,全钾含量增加4.6%—18.1%,全氮含量增加2.6%—13.2%。速效磷含量增加9.8%—39.1%,速效钾含量增加13.2%—39.1%,铵态氮含量增加8.6%—38.7%,硝态氮含量增加1.4%—9.2%。各指标的变化幅度随焚烧量的增多而加大(A3A2A1)。玉米生育期内,焚烧处理的土壤有机质含量平均恢复5.6%(A1A2A3)。与有机质相比,焚烧处理土壤微生物数量恢复程度较高,其中细菌的恢复速率最快。在玉米苗期各焚烧处理的真菌、细菌和放线菌平均数量相对于CK依次降低12.7%、17.4%、11.9%,在大喇叭口期和成熟期,微生物数量与CK间差异不显著。速效养分含量在玉米生育期显著高于CK。在玉米苗期、大喇叭口期和成熟期,相对于CK速效磷含量平均增加24.9%、27.0%、29.2%,速效钾平均增加24.0%、14.1%、15.2%,铵态氮平均增加25.5%、23.1%、20.2%,硝态氮平均增加20.8%、19.2%、19.8%。     

有机肥替代部分化肥对水稻光合速率、氮素利用率和产量的影响

农业生产中合理施用有机肥对实现化肥零增长、提高土壤肥力和保证粮食稳产高产至关重要.本试验在辽宁省沈阳市稻田以'沈农9816'为供试材料,设置7种不同处理,分别为不施氮肥(CK)、低氮150 kg ? hm-2(LN)、中氮240 kg ? hm-2(MN)、高氮330 kg·hm-2(HN)、中氮有机肥替代10％(OM...     

Synergistic effects of cadmium and NaCl on the growth,photosynthesis and ion content in wheat plants

The addition of NaCl to cadmium had significant synergistic effect on the wheat root and shoot fresh mass, relative growth rate and net assimilation rate, while showed no significant effects on the dry mass production, leaf area, leaf area ratio, leaf mass ratio and specific leaf area. Additive depression of the rate of photosynthesis and the stomatal conductance was recorded, while no significant effect on the transpiration rate was observed. The Cd stress disturbed the mineral nutrition of the wheat plants either directly or indirectly, NaCl markedly reduce the uptake and internal concentration of K and Ca in the shoot. The combination of cadmium and NaCl showed no additive effects on the content of ions in the root as well as in the shoot of wheat plants.     

夏玉米叶片水分变化与光合作用和土壤水分的关系

叶片是光合作用的重要器官,其含水量的变化必将影响光合作用,但关于叶片水分变化对光合作用的影响报道较少。以华北夏玉米为研究对象,利用三叶期不同水分梯度的持续干旱模拟试验资料,分析夏玉米叶片水分变化及其与叶片净光合速率和土壤水分的关系。结果表明:夏玉米叶片净光合速率对叶片水分变化的响应显著且呈二次曲线关系,叶片含水量约为70.30%时,叶片净光合速率为零;叶片含水量与土壤相对湿度呈非直角双曲线关系,叶片最大含水量约为85.14%。研究结果可为准确描述叶片水分变化对光合作用的影响及客观辨识夏玉米干旱的发生发展及监测预警提供参考。     

水溶性有机物对水田土壤中水溶性氮磷含量及其利用率的影响

采用田间微区试验,研究了施用有机物料对土壤氮磷的变化动态及活性的影响.结果表明,水稻生长过程中土壤溶液中水溶性氮（铵态氮、硝态氮）及磷的含量都随着时间的延长而下降,且氮、磷含量的变化与施入的化学肥料量以及溶液中DOC含量有关;有机物料施用增加了水稻的生物量和对氮、磷的吸收利用;15N示踪显示,与对照的化肥处理相比,施用有机物料处理的微区氮肥利用率及土壤残留率明显增加,同时减少了土壤氮磷的损失.     

Effect of nitrogen form and phosphorus source on the growth,nutrient uptake and rhizosphere soil property of Camellia sinensis L.

The effects of nitrogen form and phosphorus source on the growth, nutrient uptake and rhizosphere soil property of tea (Camellia sinensis L.) were investigated in a pot experiment. The experiment was performed with a compartmental cropping device, which enables the collection of rhizosphere soil at defined distances from the root of tea plant. Nitrogen was supplied as nitrate or ammonium in combination with soluble phosphorus as Ca(H₂PO₄)₂ or insoluble P as rock phosphate. The leaf dry matter production of tea was significantly greater in the treatments with NH₄ ⁺ than NO₃ ^-, whereas dry matter production of root and stem was not significantly affected. Addition of phosphorus as either source did not influence the dry matter production. The concentrations of K in root, Mg and Ca in both the shoot and root supplied with NO₃ ^- were significantly higher than in NH₄ ⁺ and influence of P sources was minor. On the contrary, Al and Mn concentrations were significantly larger in NH₄ ^--fed plants which could be attributed to remarkably increased availability of Al and Mn caused by acidification of the rhizosphere soil (the first 1-mm soil section from the root surface) with NH₄–N nutrition. The concentration of N in shoot was also significantly higher in NH₄- than in NO₃-fed plants, indicating higher use efficiency of NH₄–N. Whatever the phosphate source, rhizosphere pH declined in ammonium compared to in nitrate treatment. The pH decrease was much larger when no P or soluble P were applied and reached 0.85–1.30 units which extended to 3–5 mm away from the root surface. Exchangeable acidity, content of exchangeable Al and Mn were also considerably higher in the rhizosphere soils of NH₄ ⁺ fed tea plants. Significant amounts of P dissolved from rock phosphate accumulated in rhizosphere of NH₄ ⁺, not NO₃ ^-, suggesting that the dissolution of rock phosphate was induced by the proton excreted by tea root fed with ammonium. With soluble P addition, shoot and root P concentrations were greater in NH₄ ⁺ than in NO₃ ^- treatment and it appeared that this difference could not be sufficiently explained by the available P content in soil which was only slightly higher in NH₄ ⁺ treatment. With rock phosphate addition, the shoot and root P concentrations were hardly affected by nitrogen form, although the available P content was much higher and accumulated in the rhizosphere soil supplied with ammonium. The reason for this was discussed with regard to the inter-relationship of Al with P uptake. This revised version was published online in June 2006 with corrections to the Cover Date.     

龙须菜(Gracilaria lemaneiformis)的生长、光合作用及其对扇贝排泄氮磷的吸收

研究了不同温度、光照条件下大型藻类龙须菜 (Gracilaria lemaneiformis)的生长和光合作用特性,及其对扇贝排泄氮、磷的吸收作用。结果表明温度与龙须菜的生长和光合作用显著相关,在本实验条件下,15～25℃都适宜龙须菜生长,其中20℃龙须菜具有较高的生长率(SGR),为2.8%/d;光合作用速率随温度升高和光照的增加而升高,30℃和120 μmol/(m^２•s)时最高,最大光合作用速率（Pmax）为5.0 mg O₂/(g dw•h)。龙须菜对扇贝排泄氮、磷有较强的吸收作用,其吸收率和去除效率与放养密度和养殖时间有关。对NH4-N和PO4-P的最大去除效率分别为83.7%和70.4%,最大吸收率分别为9.9 μmol/(g ww•h)和4.3 μmol/(g ww•h)。实验证明龙须菜生长温度范围和光照范围适合中国北方海区养殖,并且能有效吸收和去除扇贝排泄氮、磷,可以作为生物滤器与贝类及其他养殖动物进行综合养殖。     

黄土丘陵区退耕草地群落优势种叶片光合生理对氮磷添加的响应

以黄土丘陵区退耕草地群落典型优势种白羊草、长芒草和达乌里胡枝子为研究对象,测定不同氮磷（主区N：0,50,100 kg N hm^-2 a^-1;副区P：0,40,80 kg P₂O₅ hm^-2 a^-1）添加处理下叶片光合气体交换参数、叶绿素荧光参数、叶片氮磷含量、光合氮利用效率（PNUE）和光合磷利用效率（PPUE）,探究不同优势种光合生理特征对外源氮磷添加的响应特征与物种差异。结果表明：单独氮添加下,3个优势种的净光合速率（P_n）、蒸腾速率、水分利用效率（WUE_i）、气孔限制值（Ls）和光系统Ⅱ（PSⅡ）活性高于或显著高于未施肥处理,白羊草和达乌里胡枝子的PNUE和PPUE以及长芒草的PPUE显著增加。单独磷添加下,仅达乌里胡枝子的P_n、WUE_i、Ls和PNUE相比未施肥处理显著增加。氮磷共同添加下,50 kg N hm^-2 a^-1处理下,施磷后达乌里胡枝子的P_n以及三个优势种的PNUE显著增加,白羊草的PPUE显著降低;100 kg N hm^-2 a^-1处理下,施磷后达乌里胡枝子的P_n和PNUE均显著增加,白羊草PPUE和长芒草的PNUE的仅在40 kg P₂O₅ hm^-2 a^-1处理下显著增加。3个优势种的P_n均与PSⅡ最大光化学效率和叶片氮含量呈显著正相关关系,长芒草和达乌里胡枝子的P_n与PSⅡ潜在活性和叶片磷含量呈显著正相关关系。总体表明,氮磷对黄土丘陵区退耕草地优势种光合生理具有一定的交互作用,物种属性和施肥水平影响其光合生理特征响应程度。     

不同土层测墒补灌对冬小麦耗水特性与光合速率和产量的影响

于2012—2014年两个冬小麦生长季,在大田条件下设置：全生育期不灌水(W₀)处理,当地定量节水灌溉(拔节期和开花期均灌水60 mm,W₁)处理,依据0～20 cm (W₂)、0～40 cm (W₃)、0～60 cm (W₄)和0～140 cm (W₅)土层土壤含水量测墒补灌处理,于拔节期和开花期补灌至土壤相对含水量为田间持水量的65%和70%,研究依据不同土层土壤含水量测墒补灌对冬小麦耗水特性、光合速率和籽粒产量的影响.结果表明：各处理拔节期灌水量为W₁、W₄＞W₃＞W₂、W₅,开花期灌水量和总灌水量均为W₅＞W₁、W₄＞W₃＞W₂,W₃总耗水量显著高于W₂处理,与W₁、W₄和W₅处理无显著差异.W₃土壤贮水消耗量高于W₁、W₄和W₅处理,其中,W₃在拔节至开花阶段和开花至成熟阶段对40～140 cm和60～140 cm土层土壤贮水消耗量均显著高于其余灌水处理.灌浆中期W₃处理小麦旗叶光合速率、蒸腾速率和水分利用效率最高,W₁和W₄处理次之,W₀处理最低.W₃处理两个生长季的籽粒产量分别为9077和9260 kg·hm^-2,水分利用效率分别为20.7和20.9 kg·hm-2·mm^-1,均显著高于其余处理,灌溉水生产效率最高.综合考虑灌水量、籽粒产量和水分利用效率,小麦拔节期和开花期适宜进行测墒补灌的土层深度为0～40 cm.     

Long-term effect of superphosphate on accumulation of soil phosphorus and exchangeable cations on a grazed,irrigated pasture site

The annual herbage dry matter yield, herbage P concentrations and quantities of P, K, Mg and Ca cycled by grazing sheep were calculated for a 37 year-old grazed pasture supplied with superphosphate at rates of 0, 188 and 376 kg ha^-1 annually. The amount and distribution of inorganic and organic P and exchangeable K, Mg and Ca in the soil below the three grazed treatments was also measured and compared with that below a wilderness area which had not been used for agriculture. Increasing rates of superphosphate increased herbage dry matter yield, herbage P concentrations and thus the amounts of P ingested and, in turn, excreted by the grazing sheep. Annual quantities of K, Mg and Ca cycled back to the pasture in the form of excreta were also increased. The increased cycling of K by animals induced by increasing superphosphate applications resulted in greater losses of K and consequently concentrations of exchangeable and non-exchangeable ‘fixed’ K in soil decreased in the order wilderness > control > 188 > 376. Differences were evident to a depth of 20 cm. Some losses of Mg during cycling also occurred and concentrations of exchangeable Mg followed the order: wilderness > control >188=376. Concentrations of exchangeable Ca increased with pasture development due to additions of Ca in lime and superphosphate. Concentrations of total soil organic P (0–4 cm) increased in the order: wilderness < control <188<376 but for inorganic P and total P the control had a lower content than wilderness indicating losses of P during cycling in the grazed control treatment. Phosphorus fractionation suggested that with increasing superphosphate rates inorganic P primarily accumulated in a form adsorbed to Al hydrous oxides and as calcium phosphate compounds whilst organic P accumulated in both labile forms and forms associated with humic compounds. In the fertilised sites both inorganic and organic P accumulated in the soil profile to a depth of 20 cm.     

有机营养液灌溉频次和灌水量对设施甜瓜产量、品质及肥水利用效率的影响

为研究高产优质甜瓜的有机管理模式,以甜瓜为试材,采用基质盆栽方式,设3种有机营养液灌溉频次(施用8次,每次每株750 mL, F₁; 施用12次,每次每株500 mL, F₂; 施用16次,每次每株375 mL, F₃)与2种单株灌水量(果实膨大前按120%日蒸腾蒸发量(ET)灌溉,之后按140%ET灌溉, W₁; 果实膨大前按140%ET灌溉,之后按160%ET灌溉, W₂),共6个试验处理,随机区组试验设计,研究了不同处理对设施甜瓜光合特性、产量、品质及肥水利用效率的影响.结果表明: 少量多次施用有机营养液可以显著提高甜瓜叶片光合速率,低灌水量显著提高果实产量和水分利用效率;高灌水量和中等有机营养液灌溉频次可使肥料利用率达到最高;少量多次有机营养液施用且相对适宜的水分供给提高了果实品质.回归分析发现,甜瓜果实维生素C含量与有机营养液灌溉频次呈指数函数y=0.214e^0.18x (R²=0.851)相关.综合考虑产量、品质、水分利用效率等因素,F₃W₁处理可在保证产量的前提下,提高果实品质,且水分利用效率最大,可以实现设施有机甜瓜肥水高效管理.     

氮、磷、钾营养对冬小麦光合作用及水分利用的影响

在中国科学院封丘农业生态实验站长期肥料实验的基础上,选择氮磷(T1)、氮钾(T2)、磷钾(T3)和氮磷钾(T4)4个肥料处理,以不施肥为对照(CK),研究了长期施用氮、磷、钾肥对小麦抽穗期和灌浆期净光合速率(Pn)、蒸腾速率(Tr)和水分利用效率(WUE)日变化的影响.结果表明:小麦抽穗期和灌浆期T4处理的Pn日变化值显著高于CK,其他处理与CK未达到显著性差异,各处理Pn日积累量大小为T4＞T1＞T2＞T3＞CK;缺氮、缺磷和缺钾均降低了叶片Pn,影响大小依次为缺氮＞缺磷＞缺钾;小麦抽穗期和灌浆期Tr日变化曲线呈单峰型,处理间日变化值差异不显著;缺氮、缺磷和缺钾均降低了叶片WUE,抽穗期,T1、T4处理的WUE日变化值显著高于CK,而T3、T2与CK差异不显著,说明缺氮、缺磷对WUE的影响最大,灌浆期,T4处理的WUE日变化值显著高于CK;不同肥料处理仅改变了小麦光合日变化的幅度,而未改变其变化规律,氮、磷、钾复合施肥有效地提高了小麦的光合生产和水分利用效率.     

土壤干旱条件下不同施钾水平对烟草光合速率和蒸腾效率的影响

研究了土壤干旱条件下,不同的施钾水平对烟草光合速率,胞间CO2浓度,气孔导度,蒸腾速率,蒸腾效率及生物量的影响。结果表明：在土壤干旱条件下适量施钾可以减少叶肉细胞光合活性的下降,消弱非气孔因素对光合的限制,增强气孔调节能力,提高蒸腾效率,并获得较高的生物量。     

Interactions between the effects of atmospheric CO2 content and P nutrition on photosynthesis in white lupin (Lupinus albus L.)

Phosphorus (P) is a major factor limiting the response of carbon acquisition of plants and ecosystems to increasing atmospheric CO2 content. An important consideration, however, is the effect of P deficiency at the low atmospheric CO2 content common in recent geological history, because plants adapted to these conditions may also be limited in their ability to respond to further increases in CO2 content. To ascertain the effects of low P on various components of photosynthesis, white lupin (Lupinus albus L.) was grown hydroponically at 200, 400 and 750 micromol mol(-1) CO2, under sufficient and deficient P supply (250 and 0.69 microM P, respectively). Increasing growth CO2 content increased photosynthesis only under sufficient growth P. Ribulose 1,5-biphosphate carboxylase/oxygenase (Rubisco) content and activation state were not reduced to the same degree as the net CO2 assimilation rate (A), and the in vivo rate of electron transport was sufficient to support photosynthesis in all cases. The rate of triose phosphate use did not appear limiting either, because all the treatments continued to respond positively to a drop in oxygen levels. We conclude that, at ambient and elevated CO2 content, photosynthesis in low-P plants appears limited by the rate of ribulose biphosphate (RuBP) regeneration, probably through inhibition of the Calvin cycle. This failure of P-deficient plants to respond to rising CO2 content above 200 micromol mol(-1) indicates that P status already imposes a widespread restriction in plant responses to increases in CO2 content from the pre-industrial level to current values.     

Soil nutrient patchiness affects nutrient use efficiency,though not photosynthesis and growth of parental Glechoma longituba ramets: both patch contrast and direction matter

Aims Most plants are clonal in nature. Clonal ramets can share water, nutrients and photosynthate, especially when they experience patchy resources. Patch contrast (i.e. a difference in resources among patches) and patch direction (i.e. source–sink relations) are among the basic attributes of spatial patchiness. Here, I hypothesize that young established ramets in nutrient-rich patches support old ramets in nutrient-poor patches when ramets are subjected to different patch contrasts and patch directions.Methods In a greenhouse experiment, old and young ramets of Glechoma longituba were grown in four combinations consisting of patch contrast and patch direction. Minus patch direction refers to a patch combination in which parent ramets grow in nutrient-rich patches while connected daughter ramets grow in nutrient-poor ones and plus patch direction is the opposite direction. I measured photosynthesis and fluorescence traits, harvested all ramets, took morphological measures, weighed their dry mass and determined their nutrient uptake and use.Important findings For parental ramets of G. longituba, patch contrast and patch direction and their interactions had no significant effects on net photosynthetic rate, maximal fluorescence yield, photochemical quenching (quenching refers to any process which decreases the fluorescence intensity of a given substance), non-photochemical quenching, nutrient uptake, biomass and stolon weight ratio. Patch direction alone significantly affected root weight ratio. Large patch contrast enhanced N use efficiency (NUE) and P use efficiency (PUE); plus patch direction decreased NUE, but increased PUE; the patch contrast by patch direction interaction affected PUE and K use efficiency (KUE). There were significant interactions between patch direction and patch contrast on PUE and KUE. It is concluded that soil nutrient patchiness may influence nutrient use strategies, but not nutrient uptake, photosynthesis and growth of parent ramets of G. longituba connected to daughter ramets, and that patch contrast and patch direction jointly affect PUE and KUE.     

异株荨麻（Urtica dioica）生长及光合特性对不同土壤水分含量的响应

异株荨麻是我国一种重要中药植物,如何对其进行人工定向培植具有重要意义。以异株荨麻扦插苗为实验材料,采用盆栽水分梯度法,按土壤相对含水量93．58％、80．74％、67．90％、55．06％和42．22％分为对照组CK,实验处理组T1,T2,T3和T4五个处理组,通过观测不同水分条件下,异株荨麻生长量、生物量变化和光合特征变化,试图探讨异株荨麻的水分适应性,寻找出适合其生长的水分范围及对生物量分配的影响,为北方地区种植栽培此类植物提供科学依据。结果发现：随土壤水分含量的降低,异株荨麻生长量和生物量积累呈先上升后下降趋势,在土壤相对含水量80．74％生长达到高峰,土壤相对含水量67．90％～80．74％为异株荨麻生长的适宜范围。净光合速率、蒸腾速率、气孔导度、气孔限制值及叶绿体色素含量的变化趋势与之相近似。在上述水分范围以外其光合功能下降、同化作用减弱,使异株荨麻生长衰退和干物质积累的减少。此外,土壤水分直接调控光合产物在地上和地下的分配以及植株个体形状,生产实践中,通过控水可以达到控制株形和根冠比的作用,用以诱导植株朝种植的预期方向生长,以达到获取植株不同部位产量的实际应用需求。     

湿地农田土壤磷素的分布、形态与有效性及磷素循环

对江汉平原四湖地区湿地农田土壤磷素的含量分布、形态、有效性、磷素循环及施肥效应进行了研究.结果表明农田土壤全磷和有效磷含量随着地势的降低呈明显降低趋势,潜育性土壤全磷和有效磷含量均极显著低于非潜育性土壤.水田土壤Ca-P、Al-P、Fe-P和O-P分别占无机磷总量的58.1%、3.7%、10.6%和27.5%,其中Ca-P和Al-P与有效磷呈高度正相关(r分别为0.9286**和0.9038**),说明Ca P和Al-P是该地区水田土壤有效磷的主要来源之一.潜育性土壤Ca-P、Al-P和Fe-P的平均含量分别比非潜育性土壤低84.0、10.2和21.1mg/kg,其差异达显著或极显著水平,证明潜育性土壤磷素降低的主要原因是Ca-P、Al-P和Fe-P的损失.五种耕作制度下潜育性稻田土壤磷素输入输出平衡值为盈余2.3～27.9kg/hm2·a,其输入输出比(1/0)为1.06～1.88.对于土壤速效磷小于5mg/kg的潜育性稻田,早、中、晚稻的最高产量施磷量分别为4.83,4.93和1.78 P2O5kg/666.7m2.     

不同土壤水分条件下中国沙棘雌雄株光合作用、蒸腾作用及水分利用效率特征

采用LI-6400便携式光合系统对野外不同生境(沟底、坡面)和田间不同土壤水分条件下中国沙棘雌雄株的净光合速率和蒸腾速率及水分利用效率特征进行了观测,结果表明,中国沙棘雌雄株在水分条件较好的生境中均表现较强的生活力,净光合速率和蒸腾速率主要受光照强度和大气温度的影响,雄株表现出更高的光合、蒸腾、水分利用效率;在水分条件较差的生境中,雌雄株均通过降低蒸腾和提高水分利用效率来适应逆境,净光合速率和蒸腾速率的影响因子增多,雄株的光合速率大幅度下降,雌株仍保持较高的光合速率,雌株的水分利用效率高于雄株.可见,在反映植物瞬时生理变化的性状方面,雌株对土壤水分减少表现出了更强的适应性,雄株对土壤水分变化表现出了更大的敏感性.