对氮素反应敏感性不同的水稻叶色基因型鉴定

氮素是水稻生长必需的大量营养元素,提高氮素的吸收利用效率是水稻育种和栽培的重要目标之一。水稻叶色与氮素水平密切相关,叶色值可作为叶片氮含量的诊断指标之一。本试验在大田不施氮素及常规施氮两个处理下,以叶片的SPAD值作为氮素能力评价参数,对146个不同基因型水稻进行了叶色深浅及对氮素敏感性不同的种质资源鉴定。通过测定抽穗前不同生育时期不同基因型水稻叶片的SPAD值,鉴定出对氮素不敏感且叶色较浅基因型7个（9103、临粳8选系、两优培粳、信粳06j1、丰糯、阳光香稻、红米稻）、对氮素不敏感且叶色较深基因型9个（9668、9002-1-1、年香粳、淮稻6号、黑稻、3优32、9910-2、矮香、方欣4号）和对氮素敏感基因型3个（白香粳、牟香粳、日本早稻）。     

低N胁迫下巴西橡胶实生苗叶片SPAD值、N素营养及农艺性状的变化

对3个品种(GT1、RRIM600、PR107)巴西橡胶(Hevea brasiliensis)实生苗进行不同N素(0%N,50%N,100%N)处理,分析比较叶片SPAD值、N素营养和农艺性状的变化及其关系。结果表明:(1)缺N胁迫明显降低了叶片SPAD值、叶片N含量和硝酸还原酶活性,缩小了叶蓬距、叶面积,且影响幅度随胁迫强度的加大而增大;(2)不同品种橡胶树实生苗对缺N胁迫的响应程度不同,总体上GT1较为敏感,PR107次之,RRIM600较不敏感;(3)橡胶树实生苗叶片SPAD值、叶蓬距、叶面积与叶片N含量、硝酸还原酶活性之间均呈显著或极显著正相关。因此,有可能采用测定叶片SPAD值、叶蓬距和叶面积等简易方法判断橡胶树新生叶蓬的N素营养状况。     

利用叶色特征监测小麦叶片的碳氮状况

研究了不同土壤水氮条件下小麦 (Triticumaestivum) 抽穗后叶片碳氮状况及其比例与叶片叶色 (SPAD值 ) 的关系。结果表明, 小麦中后期叶片氮含量和可溶性糖含量与顶部 3张叶片叶色 (SPAD值 ) 均呈显著的指数正相关, 其相关程度大小为L1>L2 >L3, 但与不同叶位叶色间的差值或比值相关并不显著 ;而叶片碳氮比与各叶位叶色相关不显著, 但与顶 1叶和顶 3叶的叶色差值呈极显著直线相关, 据此建立了基于叶色特征的叶片氮含量、可溶性糖含量和碳氮比监测模型, 检验结果显示, 顶 1叶叶色和顶 1叶与顶 3叶叶色的差值可用来有效地评估小麦叶片的碳、氮含量及碳氮比状况。     

海棠和核桃叶片叶绿素含量的时间变化

采用Minolta公司生产的SPAD-502型叶绿素计,研究我国北方2种主要果树海棠和核桃不同枝条叶片叶绿素含量的时间变化。结果表明:海棠和核桃所有叶片的SPAD平均值分别为46.3、37.3。海棠叶片早春SPAD值较高,随后缓慢增加;核桃叶片早春SPAD值较低,随后快速增加。海棠树冠西部叶片SPAD值较高,东部较低;核桃树冠东部叶片SPAD值最高。海棠树冠上、中层叶片SPAD值显著高于下层,果枝顶、中端叶片SPAD值显著高于果枝基部叶片;核桃树冠不同层次叶片SPAD值无显著异,果枝不同部位叶片SPAD值亦无显著差异。海棠和核桃非果枝叶片SPAD值略大于果枝,但无显著差异。为加强叶片叶绿素含量累积,促进光合作用,对于海棠和核桃应分别在早春及中期加强肥水管理。     

高肥力土壤条件下不同基因型花生对氮素利用的差异

在桶栽条件下,利用¹⁵N示踪技术,选用20个基因型花生为供试材料,研究了高肥力土壤条件下不同基因型花生对氮素利用的差异.结果表明:高肥力土壤条件下花生氮素营养以土壤氮为主,根瘤固氮次之,肥料氮最低.不同基因型间花生对全氮、肥料氮、土壤氮和根瘤固氮的吸收和积累均存在显著差异,基因型间遗传变异以根瘤固氮最大,肥料氮和土壤氮相当.氮素荚果生产效率和氮肥利用率基因型间差异显著,最高值分别为最低值的3.6和2.1倍.全氮、肥料氮、土壤氮和根瘤固氮的氮素收获指数基因型间均存在显著遗传变异,且以根瘤固氮的氮素收获指数基因型间遗传变异最大.花生荚果产量与不同氮源氮素积累量及氮素收获指数、氮素荚果生产效率和氮肥利用率呈显著或极显著正相关.依据花生对不同氮源氮素吸收积累和荚果产量筛选出全氮高积累高产型、肥料氮高积累高产型、土壤氮高积累高产型和根瘤固氮高积累高产型四大类型花生,其中四大类型特征兼有的有4个花生基因型.     

南方水稻氮素吸收与利用效率的基因型差异及评价

 以南方籼型水稻（Oryza sativa）品种为试验材料进行大田试验,以探讨提高水稻氮素吸收与利用效率的基因型潜力。结果表明,除早季分蘖期氮素积累量、干物质生产效率和抽穗期氮素积累量以及晚季氮素运转效率外,各基因型氮素吸收与利用效率存在显著或极显著的差异,提高水稻氮素吸收与利用效率的基因型潜力很大。基因型生育期对其氮素吸收与利用效率产生重要影响,生育期较长的基因型其氮素吸收效率、稻谷和干物质生产效率以及农艺效率较高。杂交稻氮素的生产效率、农艺效率、回收效率和收获指数较常规稻高,但二系杂交稻并没有比三系杂交稻明显提高。通过排序方式对各基因型氮素吸收与利用效率进行评价的结果表明,不同氮素吸收与利用效率指标的排序以及同一指标早晚季的排序均存在较大差异。氮素吸收与利用效率经标准化后的综合排序可对各基因型的氮素吸收与利用效率进行综合评价,吻合系数则可较好地反映各基因型早晚季氮素吸收与利用效率的排序。     

茶蚜对不同SPAD值绿色的趋性

以茶蚜(Toxoptera aurantii)为研究对象,研究其对模拟SPAD值(叶色值)绿色和不同施氮量处理茶梢的趋性。结果表明:不同虫态茶蚜对不同SPAD值绿色的趋性存在显著差异,茶树叶片含氮量与其SPAD值之间存在显著的线性关系,茶蚜各虫态对模拟绿色趋性最强的SPAD值的相应含氮量分别为:低龄若蚜在2.83%左右,高龄若蚜在2.83%~3.14%,有翅和无翅成虫在3.14%左右;而各虫态表现出最大趋性的茶树叶片相应含氮量分别为:低龄若蚜在2.64%~3.13%,高龄若蚜在2.68%~2.83%,无翅成虫在2.42%~2.84%,有翅成虫在2.63%~3.13%。表明不同虫态茶蚜对茶树叶片含氮量的需要存在差异,其结果可为茶园合理施肥以及控制蚜虫危害提供依据。     

杂交稻增密减肥处理的SPAD值光谱估算模型

响应"一控两减三基本"的要求,在不减产的前提下减少化肥用量,研究全程机械化大苗机插条件下不同增密减肥处理的水稻叶绿素相对含量(SPAD值)光谱估算模型。分析水稻叶片SPAD值与冠层一阶微分光谱的相关性,建立基于敏感波长及一阶微分光谱参数的SPAD值估算模型,用决定系数(R2)、均方根误差(RMSE)、相对误差(RE)对模型精度进行评价。结果表明:6个处理在634～652 nm、655～668 nm、497～552 nm及687～711 nm波段内达极显著相关,相关系数均达到0.700以上;以敏感波长为自变量估算SPAD值的模型中,低密度减肥的多项式模型估测效果最佳,其建模集R2、RMSE和RE分别为0.766、1.185和2.152%,验证集R2、RMSE和RE分别为0.729、0.364和0.752%;以光谱参数为自变量的估算模型中,中等密度减肥模型的估测效果最好,其建模集R2、RMSE和RE分别为0.703、1.314和2.359%,验证集R2、RMSE和RE分别为0.763、0.620和1.198%。研究发现:在同密度条件下,减肥会导致SPAD值降低,长势偏弱;移栽密度越大,光谱反射率相对越高;移栽密度对水稻冠层光谱反射率的影响大于施肥水平。各处理均表现为差值光谱指数(DSI)的模型效果最优,说明敏感波长及光谱参数的选择对模型的构建至关重要。     

流溪河森林公园六种常见阔叶树SPAD 值的变化与种间差异

为探讨亚热带树木叶片叶绿素SPAD 值的分布规律, 以流溪河森林公园常绿阔叶林的鸭脚木(Scheffleraoctophylla)、罗浮锥(Castanopsis faberi)、黄樟(Cinnamomum porrectum)、猴耳环(Pithecellobium clypearia)、中华杜英(Elaeocarpus chinensis)和黧蒴(Castanopsis fissa)6 种植物为研究对象, 分析植物种间SPAD 值的差异, 不同方向叶片SPAD 值的差异以及SPAD 在叶片各部位的分布。结果表明: 植物种间SPAD 值存在显著差异, 物种与叶片方向和叶片部位对SPAD 值存在显著的交互作用。各树种叶绿素SPAD 值普遍以西边的叶片较低, 体现出与北半球西南朝向受到太阳辐射时间更长这一现象呈负关联。叶绿素SPAD 值在叶片不同部位的分布则表现为: 叶基的SPAD 值最大, 其次为叶中部, 叶尖SPAD 值最小, 中华杜英和黧蒴叶基和叶中部的SPAD 值无显著差异, 叶基和叶尖则差异显著; 其余4种植物SPAD 值在叶片各部位的分布则差异不显著。通过监测该森林公园主要树种的叶绿素SPAD 值, 可以及时获取其光合作用效能和营养状况等信息, 了解其生态系统的生态功能。将SPAD-502 叶绿素计测定叶片叶绿素含量的方法应用于阔叶树的研究中, 以期为野外测定树木叶片叶绿素含量提供参考, 为完善SPAD-502 叶绿素计在林业方面的的应用提供科学依据。     

不同密度樟树(Cinnamomum camphora)幼苗生长和叶片性状对氮磷添加的响应

人类活动改变了氮素从大气向陆地生态系统输入的方式和速率,进而导致森林生态系统养分变化和失衡。研究氮磷添加对不同密度樟树(Cinnamomum camphora)幼苗生长和叶片性状的影响,可以为全球氮磷沉降背景下亚热带地区樟树人工林的经营管理提供依据。本试验以1年生樟树幼苗为试验材料,选择氯化铵(NH_4Cl)作为氮肥模拟大气氮沉降,以二水合磷酸二氢钠(NaH_2PO_4·2H_2O)模拟磷添加。氮磷处理设置CK、施N、施P和施N+P 4个水平,种植密度设置10、20、40和80株·m~(-2 )4个水平。实验数据表明:N、P和N+P处理对樟树幼苗的苗高和地径均有促进作用,且N+P处理对幼苗生长的促进效果最好。N、P和N+P处理在整体上均能增加幼苗叶片的SPAD值,N和N+P处理均增加了幼苗叶片的比叶面积(SLA),而P处理减少了幼苗的SLA。随着种植密度的增大,N、P和N+P处理下樟树平均单株幼苗的苗高、地径、SPAD值呈现下降的趋势,各施肥处理下叶片的SLA变化规律不明显。密度和氮磷添加对叶片的SPAD值产生显著的交互作用。     

Effects of soil nitrogen levels on growth and defense of the native and introduced genotypes of alligator weed

土壤氮水平对喜旱莲子草原产地和引入地基因型生长和防御的影响 同种植物生长在资源丰富生境中的个体,其防御水平被认为低于生长在资源匮乏生境中的个体。然而,生境的养分水平如何影响植物的诱导抗性和耐受性,以及这种影响在入侵植物的原产地和引入 地种群间是否存在差异,目前均知之甚少。本研究以入侵植物喜旱莲子草(Alternanthera philoxeroides)的原产地阿根廷和引入地美国的基因型为研究对象设计同质园实验,以探究土壤氮水平对植物的生长、组成和诱导性[莲草直胸跳甲(Agasicles hygrophila)取食诱导]化学防御以及耐受性的影响。实验中,我们测定了植物总生物量、伸长速率(生长速率的表征)以及叶片和根系中总碳、总氮和三萜皂苷(化学防御物质)的含量。研究结果显示,植物在低土壤氮水平下表现出较高的组成抗性(植物在低土壤氮水平下的叶片三萜皂苷含量高于其在高土壤氮水平的33%)和耐受性[植物被取食后总生物量下降的程度更低(植物在高土壤氮水平和低土壤氮水平下被取食后总生物量分别下降了24%和15%)],而在高土壤氮水平下表现出较高的诱导抗性(在高土壤氮水平下的植物被取食后叶片三萜皂苷含量与空白对照的植物相比升高了24%)。植物的组成抗性和耐受性与生长速率存在权衡,但诱导抗性与生长速率存在显著的正相关性。此外,引入地基因型在低土壤氮水平下叶片碳含量显著低于原产地基因型(-6%),但这种差异在高土壤氮水平下消失。这些结果表明,土壤氮水平 影响植物对不同防御策略的选择偏好,并且在决定引入地基因型的表现时与植食作用存在交互作用。     

夜间变暖提高荫香叶片的光合能力

研究了不同氮供应的条件下夜间变暖对荫香叶片光合能力的影响。当植株生长在相同的日间温度(25℃),而夜间温度从18℃增至20℃时,叶片的光合速率增高(p<0.05)。高氮供应的植株,夜间变暖下其叶片光合速率较低氮供应的高,氮供应增高能促进夜间变暖提高叶片光合速率的效应。在低氮供给和夜间变暖下,植株叶片的光下呼吸和暗呼吸的增高显著(p<0.05)。无论在高氮或低氮供应下,生长在夜间变暖下的植物,其叶片的R ub isco最大羧化速率(Vcm ax)和光合电子传递最大速率(Jm ax)增高(p<0.05),氮供应能增强夜间变暖对Vcm ax和Jm ax的正向效应。夜间变暖降低植株叶片的比叶重,而增加单位叶干重的氮含量(Nm),单位叶面积的氮含量(Na)没发生明显变化。随着全球气候变化,夜间趋暖将有利于树木叶片光合能力的提高,结合高氮供给将会明显地增高植物的碳固定。     

Wheat ear carbon assimilation and nitrogen remobilization contribute significantly to grain yield

The role of wheat ears as a source of nitrogen (N) and carbon (C) in the grain filling process has barely been studied. To resolve this question, five wheat genotypes were labeled with ¹⁵N‐enriched nutrient solution. N remobilization and absorption were estimated via the nitrogen isotope composition of total organic matter and Rubisco. Gas exchange analyses showed that ear photosynthesis contributed substantially to grain filling in spite of the great loss of C due to respiration. Of the total kernel N, 64.7% was derived from the N acquired between sowing and anthesis, while the remaining 35.3% was derived from the N acquired between anthesis and maturity. In addition, 1.87 times more N was remobilized to the developing kernel from the ear than from the flag leaf. The higher yielding genotypes showed an increased N remobilization to the kernel compared to the lower yielding genotypes. In addition, the higher yielding genotypes remobilized more N from the ears to the kernel than the lower yielding genotypes, while the lower yielding genotypes remobilized more N from the flag leaf to the kernel. Therefore, the ears contribute significantly toward fulfilling C and N demands during grain filling.     

Carbohydrate Metabolism in Leaf Meristems of Tall Fescue : II. Relationship to Leaf Elongation Rates Modified by Nitrogen Fertilization

Our objective was to examine alterations in carbohydrate status of leaf meristems that are associated with nitrogen-induced changes in leaf elongation rates of tall fescue (Festuca arundinacea Schreb.). Dark respiration rates, concentrations of nonstructural carbohydrates, and soluble proteins were measured in leaf intercalary meristems and adjacent segments of elongating leaves. The two genotypes used differed by 43% in leaf elongation rate. Application of high nitrogen (336 kilograms per hectare) resulted in 140% higher leaf elongation rate when compared to plants receiving low nitrogen (22 kilograms per hectare). Leaf meristems of plants receiving high and low nitrogen had dark respiration rates of 5.4 and 2.9 microliters O₂ consumed per milligram structural dry weight per hour, respectively. Concentrations of soluble proteins were lower while concentrations of fructan tended to be slightly higher in leaf meristems of low-nitrogen plants when compared to high-nitrogen plants. Concentrations of reducing sugars, nonreducing sugars, and takadiastase-soluble carbohydrate of leaf meristems were not affected by nitrogen treatment. Total nonstructural carbohydrates of leaf meristems averaged 44 and 39% of dry weight for low- and high-nitrogen plants, respectively. Within the leaf meristem, approximately 74 and 34% of the pool of total nonstructural carbohydrate could be consumed per day in high- and low-nitrogen plants, respectively, assuming no carbohydrate import to the meristem occurred. Plants were able to maintain high concentrations of nonstructural carbohydrates in leaf meristems despite a 3-fold range in leaf elongation rates, suggesting that carbohydrate synthesis and transport to leaf intercalary meristems may not limit leaf growth of these genotypes.     

High Nitrogen Use Efficiency in Rice Genotypes is Associated with Higher Net Photosynthetic Rate at Lower Rubisco Content

Contrasting rice genotypes differing in leaf mass ratio (LMR) and leaf nitrogen content were screened. A strong inverse relationship was observed between ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) content and its efficiency estimated as the ratio of net photosynthetic rate (P_N) to Rubisco content. Similarly, an inverse relationship between the specific activity of fully activated Rubisco and its content was observed. This suggests that a down regulation of Rubisco may occur if the efficiency of the enzyme is superior. Genotypes IET 12989 and IET 13567 recorded higher P_N together with lower Rubisco content in comparison with other genotypes measured. These genotypes showed low LMR and low nitrogen content and hence could be considered as efficient nitrogen users. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rice leaf growth and water potential are resilient to evaporative demand and soil water deficit once the effects of root system are neutralized

Rice is known to be sensitive to soil water deficit and evaporative demand, with a greatest sensitivity of lowland‐adapted genotypes. We have analysed the responses of plant water relations and of leaf elongation rate (LER) to soil water status and evaporative demand in seven rice genotypes belonging to different species, subspecies, either upland‐ or lowland‐adapted. In the considered range of soil water potential (0 to ?0.6 MPa), stomatal conductance was controlled in such a way that the daytime leaf water potential was similar in well‐watered, droughted or flooded conditions (isohydric behaviour). A low sensitivity of LER to evaporative demand was observed in the same three conditions, with small differences between genotypes and lower sensitivity than in maize. The sensitivity of LER to soil water deficit was similar to that of maize. A tendency towards lower sensitivities was observed in upland than lowland genotypes but with smaller differences than expected. We conclude that leaf water status and leaf elongation of rice are not particularly sensitive to water deficit. The main origin of drought sensitivity in rice may be its poor root system, whose effect was alleviated in the study presented here by growing plants in pots whose soil was entirely colonized by roots of all genotypes.     

Influence of soil applications of nitrogen on nitrate reductase activity,leaf and grain protein content in sorghum

Summary Three sorghum genotypes, L.187, SK5912 and RCFA×L.187 (the latter being a hybrid) were field grown under four nitrogen application rates and replicated four times. The experiments were of complete randomized plot design and conducted in 1976, 1977 and 1978.Nitrate Reductase Activity (NRA) was measured at 5, 7, 9, 11, 13, and 15 weeks and at 18, 19, 20 and 21 weeks after planting in 4th vegetative leaf and flag leaf respectively. Flag leaf, 4th leaf and grain protein contents were also measured.Nitrogen application generally increased NRA in both 4th leaf and flag leaf in the 3 genotypes at all the sampling dates.NRA of the hybrid, RCFA×L.187 was consistently higher than those of SK5912 and L.187 (both straight varieties).NRA of 4th leaf was negatively correlated with leaf protein but flag leaf protein tended to increase with applied nitrogen.Flag leaf NRA was positively and significantly correlated with grain protein indicating an important part played by the flag leaf relative to protein accumulation of the developing grain.     

烟草不同基因型耐低氮能力差异评价

以单株叶重及其氮素反应指数作为耐低氮能力的评价指标,分析了烟草种质资源的耐低氮能力以及单株叶重及其氮素反应指数与主要农艺性状间的相关关系。结果表明,不同施氮水平下多数农艺性状基因型间差异较大,在低氮水平下表现最大;和其他农艺性状相比,单株叶重在不同氮素水平间平均差异最大。不同施氮水平下,单株叶重均与最大叶叶面积、单株生物量呈显著或极显著正相关;单株叶重的氮素反应指数与单株叶重、生物量呈显著或极显著正相关,且低氮水平下单株叶重的氮素反应指数与上述性状间的相关性比中氮水平下更为密切。在供试的36个烟草品种中,永定400号、金烟6号、红花大金元、G80、Nc82等烟草种质具有较强的耐低氮能力,可以作为氮高效的烟草品种利用。     

不同有机氮效率的甜菜基因型筛选及差异分析

通过对不同基因型甜菜土壤有机氮利用及吸收效率的筛选和差异分析,为土壤有机氮高效基因型甜菜的栽培及品种选育提供理论依据。2014-2015年选取100份不同基因型的甜菜材料通过室内及田间试验在甜菜的不同发育阶段比较并分析土壤有机氮效率,筛选出对有机氮利用及吸收效率均显著差异的高效和低效基因型甜菜材料。结果表明,初步筛选得到的有机氮高效基因型甜菜材料KWS8138、HI0466和有机氮低效基因型甜菜材料BETA176、T230苗期全株及根部有机氮利用效率（Organic Nitrogen Use Efficiency,ONUE）差异显著;之后通过田间试验对有机氮吸收效率（Organic Nitrogen Assimilation Efficiency,ONAE）做了进一步筛选,发现KWS8138不但对ONUE有显著优势,还具有较高的有机氮素吸收能力,包括苗期之后对土壤有机氮素的运转量较高,合理的根冠比等。有机氮低效基因型甜菜材料BETA176的有机氮素吸收利用能力很弱、氮素转运能力过低等限制了植株对有机氮素的合理利用,不利于有机氮效率的提高。因此确定KWS8138为有机氮高效基因型材料,BETA176为有机氮低效基因型材料,均可作为进一步试验的材料。有机氮高效基因型甜菜较高的土壤有机氮转运量及合理的根冠比促进了其对有机氮素的吸收,是有机氮高效的基础。较高的干物质生产效率反应了甜菜对有机氮素的高效利用,是有机氮高效的关键。     

Comparative water use and nitrogen relationships in a mistletoe and its host

Summary The impact of the xylem-tapping mistletoe Phoradendron juniperinum on the nitrogen and water relations of its host Juniperus osteosperma was investigated under natural field conditions. Leaf conductance, leaf water potential, and leaf Kjeldahl nitrogen contents were followed through the growing season on mistletoes, infected junipers (separating infected from uninfected stems) and uninfected junipers. Infected trees experienced lower leaf water potentials than uninfected trees and also had lower leaf conductances and lower leaf nitrogen contents. Infected juniper stems had higher conductances than uninfected stems. Mistletoes had higher leaf nitrogen contents than their hosts and much of this nitrogen appeared as arginine, a potential nitrogen storage compound. Photosynthetic rates (per unit leaf area) were significantly higher in junipers than in the mistletoe, and higher in the uninfected than infected junipers. Water use efficiencies as estimated by carbon isotope ratios were significantly lower in mistletoes than in their hosts. Increased mistletoe infestation appeared to increase absolute water use efficiency of both host and mistletoe.Dedicated to Professors D. Wiens (Salt Lake City) and H. Ziegler (München) for initiating our curiosity in mistletoes