春玉米叶片SPAD值与氮含量及产量的相关性研究

通过田间小区试验,研究不同时期玉米叶片SPAD值与叶绿素、氮含量及产量的相关性,确定SPAD值测定的最佳叶位及时期。结果表明,上位叶SPAD值对氮素的敏感时期顺序为12叶期>10叶期>8叶期;穗位叶SPAD值对氮素的敏感时期顺序为抽雄期>灌浆期>蜡熟期。叶片SPAD值可以很好的反映植株叶绿素和氮含量及产量水平,以某一特定叶片的SPAD值来诊断春玉米氮素营养状况和推荐追肥时期时,10叶期是较为理想的测定时期;作为早期预测玉米产量的指标,12叶期为最佳时期。测定SPAD值方法简便、快捷,不破坏叶片生长,可作为早期预测玉米产量的指标。     

Improvement of nitrogen management in rice paddy fields using chlorophyll meter (SPAD)

Optimum rate and timing application of nitrogen (N) fertilizer are most crucial in achieving high yield in irrigated lowland rice. In order to assess leaf N status, a semidwarf rice cultivar (Khazar) was grown with different N application treatments (0, 40, 80, and 120 kg N ha⁻¹ splited at transplanting, midtillering, and panicle initiation stages) in a sandy soil in Guilan Province, Iran, in 2003. The chlorophyll meter (SPAD 502) readings were recorded and leaf N concentrations were measured on the uppermost fully expanded leaf in rice plants at 10-day internals from 19 days after transplanting to grain maturity. Regression analysis showed that the SPAD readings predicted only 23% of changes in the leaf N concentration based on pooled data of leaf dry weight (N _dw) for all growth stages. However, adjusting the SPAD readings for specific leaf weight (SPAD/SLW) improved the estimation of N _dw, up to 88%. Specific leaf weight (SLW), SPAD readings, leaf area and weight as independent variables in a multiple regression analysis predicted 96% of the N _dw changes, while SPAD readings independently predicted about 80% of leaf N concentration changes on the basis of leaf area (N _a). It seems that chlorophyll meter provides a simple, rapid, and nondestructive method to estimate the leaf N concentration based on leaf area, and could be reliably exploited to predict the exact N fertilizer topdressing in rice.     

冬油菜叶片SPAD的时空分布和氮素诊断的叶位选择

在大田试验条件下测定分析不同施氮水平冬油菜关键生育期SPAD值的时空分布特征,并对不同叶位及叶片不同部位SPAD值与叶绿素含量、叶片含氮量、植株全氮含量及籽粒产量之间的相关性进行分析,探求应用SPAD仪诊断油菜氮素营养状况的最佳测试叶位及位点。结果表明,油菜主茎顶部4片完全展开叶SPAD值存在显著空间差异,增加施氮量能显著提高各叶位叶SPAD值,同时减少叶位间的差异;六叶期、蕾薹期以顶4叶（TL4）SPAD值对氮素的敏感性最大,初花期和盛花期则最低。不同部位间,六叶期和初花期以中部SPAD值对施氮量增加的响应最敏感,盛花期则最迟钝,蕾薹期介于顶部和基部之间。综合分析认为,应用SPAD仪监测油菜氮素营养状况的最佳测试叶位和位点为主茎顶4片完全展开叶中部,该部位SPAD值与叶绿素含量、叶片含氮量和植株全氮含量之间的相关性均达到显著或极显著水平,满足氮素营养快速诊断的要求。     

Evaluation of the SPAD Value in Faba Bean (Vicia fabaL.) Leaves in Relation to Different Fertilizer Applications

Abstract

The correlations of the reading of a portable chlorophyll meter (SPAD-502) with the chlorophyll and N contents of leaves of two faba bean (Vicia fabaL.) cultivars, Japanese (Ryousai-issun) and Egyptian (Cairo 241), were examined. The SPAD readings positively correlated (ρ<0.01) with the chlorophyll contents and the r² values were 0.99 and 1.00 for Ryousai-issun and Cairo 241, respectively. A close linear relationship (ρ0.001) was observed between SPAD reading and total leaf N content at the pod development stage of faba bean plants with r² = 0.88 and 0.99 for Ryousai-issun and Cairo 241, respectively. The SPAD reading was the highest in the 2^nd to 4^th leaves counted from the top (the youngest fully expanded leaves). The changes in leaf chlorophyll content of both cultivars from 3 weeks after transplanting to the ripening stage showed an incomplete “M” type curve. SPAD readings were significant¬ly higher in Ryousai-issun than in Cairo 241 throughout the growth season. Organic fertilizers application improved faba bean plant growth. These results suggest that the SPAD-502 chlorophyll meter can be used to measure chlorophyll and nitrogen contents of faba bean leaves for quick screening faba bean genotypes.     

夏玉米叶片叶绿素含量的时空动态及其与植株含氮率关系的研究

在不同施氮水平下,研究了夏玉米郑单958叶片叶绿素含量(SPAD值)的时空动态变化及其与植株含氮率的关系。结果表明,夏玉米子粒生长期棒三叶SPAD值与棒三叶、全株总叶片及整株含氮率均有极显著线性相关关系。不同施氮水平子粒生长期叶片叶绿素含量的空间分布均以穗位叶为中心呈现出中间高两边低的趋势,SPAD值依次为中部叶>上部叶>下部叶。施氮可调节各部位叶片SPAD值或氮素含量,但并未改变其空间分布模式。不同施氮水平子粒生长期上部和中部叶片叶绿素含量随时间的动态变化总体上呈现先增大后减小的趋势,下部叶片的叶绿素含量则呈持续下降的趋势。夏玉米不同叶位叶片对氮肥的反应均表现在一定范围内(N≤207 kg/hm²),子粒生长期各叶片叶绿素含量随施氮量的增加而增加,当总施氮量增为276 kg/hm²时,各叶片叶绿素含量不再明显增加,相对来说中部叶比上部和下部叶对氮肥的反应更为敏感。     

Functional dynamics of the nitrogen balance of sorghum. II. Grain filling period

Maintenance of green leaf area during grain filling can increase grain yield of sorghum grown under terminal water limitation. This ‘stay-green’ trait has been related to the nitrogen (N) supply–demand balance during grain filling. This study quantifies the N demand of grain and N translocation rates from leaves and stem and explores effects of genotype and N stress on onset and rate of leaf senescence during the grain filling period. Three hybrids differing in potential height were grown at three levels of N supply under well-watered conditions. Vertical profiles of biomass, leaf area, and N% of leaves, stem and grain were measured at regular intervals. Weekly SPAD chlorophyll readings on main shoot leaves were correlated with observed specific leaf nitrogen (SLN) to derive seasonal patterns of leaf N content. For all hybrids, individual grain N demand was sink determined and was initially met through N translocation from the stem and rachis. Only if this was insufficient did leaf N translocation occur. Maximum N translocation rates from leaves and stem were dependent on their N status. However, the supply of N at canopy scale was also related to the amount of leaf area senescing at any one time. This supply–demand framework for N dynamics explained effects of N stress and genotype on the onset and rate of leaf senescence.     

施氮水平及方式对玉米冠层NDVI、氮含量、叶绿素和产量的影响

在不同施氮水平和方式（不追肥和拔节期追肥）的田间试验条件下,采集并测定玉米不同生育期的冠层归一化植被指数（NDVI）、叶片SPAD值、叶绿素含量、叶片全氮含量和产量,研究不同氮素水平下各指标间的相互关系。结果表明,在不同生育期玉米叶片叶绿素含量和冠层NDVI值均随施氮量的增加而增大,追肥能显著提高叶片叶绿素含量和冠层NDVI值,灌浆期玉米叶片叶绿素含量增加幅度最大。冠层NDVI值与叶片氮含量、叶绿素含量的相关系数在各生育期均达到显著或极显著水平,叶片SPAD值与叶绿素含量的关系同冠层NDVI值一致,两者均可以对玉米进行氮素营养的诊断,但NDVI比SPAD更具有快速可靠的优点。追肥较不追肥处理有明显增产效果,平均增产幅度为29.23%,最大增幅为44.13%。     

利用SPAD值诊断赣花7号氮素营养研究

为适时精确诊断赣花7号的氮素营养状况,通过设置6个氮素水平（施纯氮0、75、150、225、300、375 kg/hm2）,在不同时期（出苗后30、45、60、75和90 d）分别测定花生不同叶位（主茎倒一完全叶、倒二完全叶和倒三完全叶）的SPAD值和相应叶位叶片的含氮量,分析其施氮水平、SPAD值和叶片含氮量之间的关系,并进行方程的拟合。结果显示：施氮水平与SPAD值、叶片含氮量之间呈显著的指数相关,SPAD值和叶片含氮量之间呈显著的线性相关,并且在各叶位中,以主茎倒3叶的相关性最好,其可作为氮素诊断的理想叶位。     

Comparison of petiole nitrate concentrations,SPAD chlorophyll readings,and QuickBird satellite imagery in detecting nitrogen status of potato canopies

Nitrogen (N) management is critical in optimizing potato yield and quality and reducing environmental pollution. Six N rates from 34 to 270 kg ha⁻¹, and different timing of N application were used in a 3-year field experiment to contrast SPAD-502 chlorophyll meter and QuickBird satellite imagery data against the conventional petiole sampling technique for assessing canopy N status. Overall treatment variations in SPAD readings were consistent with those in petiole nitrate-nitrogen (NO₃-N) concentrations. However, the ability of the SPAD meter to detect treatment differences varied with growth stage and growing season. Severe N deficiency was detected about 1 month after emergence with SPAD readings, but as early as 2 weeks after emergence with petiole NO₃-N concentrations. Petiole NO₃-N concentrations tended to differentiate more treatment variations than SPAD readings at all growth stages except at hilling. N deficiency was detected with QuickBird image-derived vegetation indices (VIs) at the hilling stage in 2002, but not in 2003. At the post-hilling stage, treatment differences in VI values were minimal and insignificant except very late in the growing season. SPAD meters could be used as an indirect method for detecting N deficiency at the hilling stage when making supplemental N applications, but they are not as sensitive as the petiole sampling method. The sensitivity of QuickBird imagery to canopy N variations needs to be further tested with more pixel data. However, cloud interference and high cost of images could limit the use of QuickBird data in making timely management decisions.     

施氮对冬水田杂交中稻本田生长期叶片叶绿素含量的影响

以18个杂交中稻组合为材料,通过施氮与不施氮(CK)处理,研究了四川冬水田区杂交水稻本田生长期间叶片叶绿素含量(SPAD值)受氮肥影响的敏感时期及主要生育时期的敏感叶位.结果表明,本田叶片叶绿素含量(SPAD值)受氮肥影响的敏感时期有分蘖期、最高苗期、拔节一抽穗期和籽粒灌浆结实中后期,施氮处理与CK叶片SPAD值的差值表现为分蘖初期和籽粒灌浆结实中后期较大,其余时期较小,其中移栽后第9～11天秧苗叶绿素含量受氮肥的影响最大,可作为测苗确定蘖肥施氮量的最佳时期;各叶位叶片的叶绿素含量受氮肥影响的程度以下部叶片较大,顶4叶是反应植株氮素状况最好的指示叶.     

应用SPAD值预测小麦叶片叶绿素和氮含量的初步研究

2003～2004年以中筋小麦品种扬麦11号、WH510和徐州26为试验材料,研究不同生育时期(拔节、孕穗、抽穗)不同叶位叶片SPAD值变化特征及其与叶片叶绿素含量、全氮含量及NO3--N含量的关系,旨在为小麦上应用SPAD快速诊断施肥提供理论依据。结果表明,不同品种及不同叶位小麦叶片SPAD值明显不同;小麦叶片SPAD值与叶绿素含量之间的关系因品种和生育时期的不同而有明显差异,同一品种小麦不同叶位叶片SPAD值与叶绿素含量呈极显著正相关。小麦叶片SPAD值与全氮含量呈正相关,SPAD值高,全氮含量也高,可以用SPAD值估算全氮含量进行小麦氮素营养状况诊断,但同一品种不同叶位SPAD值与全氮含量的关系表现不一致,即用SPAD值来诊断小麦叶片氮含量时应选择完全展开并已进入功能盛期的叶片。小麦叶片SPAD值与NO3-N含量相关性不显著。     

Leaf Positions of Potato Suitable for Determination of Nitrogen Content with a SPAD Meter

Abstract

Hand-held SPAD meter can be used to evaluate the leaf nitrogen status of potato. For practical use, it is necessary to select a proper compound leaf, a proper leaflet within compound leaf and position of leaflet suitable for measurement. Therefore, field experiments were conducted in northern China in 2009 and 2010. The SPAD values, plant growth, N uptake of potato plants at tuber initiation and tuber bulking stages under different N supply levels, and final tuber yields were examined. The criteria for determining the most suitable leaf, leaflet and position within a leaflet are that the SPAD values show less variation at a given N supply level, and show a more sensitive response to different nitrogen levels. Our results showed that the coefficients of variance of SPAD values ranged from 8.7 to 25.9% with a leaf N concentration range of 2.1 to 3.8 gN 100 g-¹ at tuber initiation stage, and 7.2 to 21.6% with leaf N concentration range of 0.96 to 1.26gN 100 g-¹ at the tuber bulking stage. The SPAD values of the 4th compound leaf from apex were more stable and more sensitive to the nitrogen level than those of other leaves, suggesting that the 4th compound leaf is suitable for estimating the leaf N status using a SPAD meter. Within a compound leaf, the SPAD value of the top leaflet was more sensitivethan the other leaflets to nitrogen supply, whereas it was less stable, making it difficult to chose the leaflet for measurement. However, the top leaflet emerges and expands much earlier than the side leaflets, and should be better for SPAD value measurement. The SPAD measurements at the top point of the top leaflet of the 4th leaf demonstrated both less variation and higher sensitivity to nitrogen supply. Therefore, we conclude that the top point of the top leaflet of the 4th compound leaf is the best position for potato N status diagnosis using a SPAD meter.     

Effect of Leaf Phosphorus and Potassium Concentration on Chlorophyll Meter Reading in Rice

Abstract

Chlorophyll meter (SPAD) is a convenient tool to estimate leaf nitrogen (N) concentration of rice plants. There is no information on the effects of leaf phosphorus (P) and potassium (K) concentration on SPAD readings and on the relationship between SPAD values and leaf N concentration in the literature. In 1996 dry season, cv IR72 was grown at the International Rice Research Institute (IRRI) and the Philippine Rice Research Institute (PhilRice) under various N, P and K fertilizer combinations. SPAD measurements were made on the topmost fully expanded leaves at mid-tillering and panicle initiation. The leaves were then detached, dried and analyzed for N, P and K. The SPAD values were highly correlated with leaf N concentration (r = 0.93 to 0.96). Fertilizer-K application did not affect SPAD values, leaf N concentration, or the relationship between the two. Phosphorus deficiency reduced leaf N concentration at mid-tillering, but increased leaf N concentration at panicle initiation when the same amount of N was applied. The SPAD values were 1 to 2 units greater for zero-P plants than P-treated plants at a given leaf N concentration at mid-tillering. At panicle initiation, the relationship between SPAD values and leaf N concentration was not significantly affected by leaf P status. These results suggest that a different regression equation between SPAD values and leaf N concentration should be used to estimate leaf N concentration of P-deficient and P-sufficient rice leaves at vegetative stage using a SPAD.     

Chlorophyll meter to predict nitrogen sidedress requirements for short-season cotton (Gossypium hirsutum L.)

A two-location experiment was carried out at five to six nitrogen levels to study the relationship between chlorophyll-meter readings (SPAD values) and physiological or yield traits in short-season cotton. The results showed that there were highly significant (P<0.01) linear relationships between SPAD values and contents of both nitrogen and chlorophyll at each growth stage, and as well as with the daily increase in plant height during early flowering. The relationship between nitrogen concentration and SPAD was stronger when nitrogen was expressed on a leaf area (N_a) rather than on a dry weight (N_dw) basis. Significant curvilinear relationships were found between SPAD values at various stages and photosynthetic intensity, lint yield, and total boll number per hectare, respectively. Furthermore, the linear regressions between SPAD values and N fertilizer levels were highly significant (P< 0.01), and before the boll opening stage, the slopes of these regressions were similar (0.040–0.041) at the two locations. These data provided evidence that the chlorophyll meter could be used to determine sidedress N requirements of short-season cotton before boll opening stage. Critical SPAD levels for maximum lint yield were established as 32.4, 33.1, 35.0, 43.55, and 39.7 at early flowering, flowering peak, boll forming, the beginning of boll opening and boll opening stages, respectively. It was also established that 24.2–25.0 kg ha⁻¹ increase in N application should be necessary for each unit decrease in SPAD value below the critical level.     

马铃薯氮素营养状况的SPAD仪诊断

以马铃薯品种克新1号为材料,研究了叶片SPAD值、叶片全氮含量、叶绿素含量以及块茎产量随供氮水平的变化规律及相互关系,旨在为使用叶绿素仪进行马铃薯无损伤氮素诊断和推荐施肥奠定基础。研究结果表明,从马铃薯苗期到块茎淀粉积累各个生育阶段叶片的SPAD测定值均与马铃薯叶片含氮量呈显著正相关关系。除苗期外,块茎形成期、块茎膨大期、淀粉积累期的马铃薯叶片含氮量和叶片SPAD值随土壤施氮量的变化均表现为线形加平台的模式。因此马铃薯块茎形成期后叶片的SPAD读数可揭示马铃薯的氮素营养状况。统计分析结果还表明,叶片SPAD值与块茎相对产量呈线形加平台的数量关系模式,据此确定了应用叶绿素仪SPAD-502进行马铃薯推荐施肥的SPAD临界值为块茎形成期47.3、块茎膨大期45.1、淀粉积累期40.2。     

外源糖和氮对春小麦花后物质生产的影响

为了解花后养分供应对春小麦产量形成的调控效应,以春小麦品种龙麦33为试验材料,分析了叶面喷施糖、氮物质(5%蔗糖和2%尿素)后小麦花后干物质积累、齐穗后群体生长率(CGR)、旗叶SPAD值、净光合速率、可溶性糖含量和全氮含量的变化。结果表明,与对照相比,叶面喷施糖、氮后小麦穗粒数和千粒重均增加,并分别增产 6.86%和15.82%。 外源糖、氮使小麦花后光合物质积累量及其对籽粒产量的贡献率提高,其中外源糖的效果更明显;外源糖、氮对CGR有显著的促进作用;外源氮显著提高收获指数（增幅11.76%）,而外源糖使收获指数略有下降（降幅0.085%）;外源糖、氮分别降低和增加旗叶SPAD值,但均提高旗叶净光合速率和全氮含量,降低旗叶可溶性糖含量和糖氮比值(C/N)。可见外源糖、氮对春小麦花后碳、氮代谢和物质生产有一定的调节作用,可促进小麦高产。     

Photosynthetic response and nitrogen use efficiency of sugarcane under drought stress conditions with different nitrogen application levels

Drought stress which often occurs during early growth stage is one constraint in sugarcane production. In this study, the response of sugarcane to drought and nitrogen application for physiological and agronomical characteristics was investigated. Two water regimes (well-watered and drought stress from 60 to 120 day after transplanting) and four nitrogen levels (0, 4.4, 8.8 and 13.2 g pot^?1 equivalent to 0, 90, 180 and 270 kg ha^?1, respectively) were assigned in a Split-plot design with three replications. The results showed that photosynthetic responses to light intensity and intercellular CO₂ concentrations of sugarcane were different between fertilized and non-fertilized treatments. Photosynthetic rates of 180 and 270 N treatments, normally, were significantly higher than that of 90 N, but not significant at drought conditions. Photosynthetic rates of 0 N treatment were the lowest under both conditions. Higher nitrogen application supported higher photosynthetic rate, stomatal conductance, and chlorophyll content because of higher nitrogen concentration accumulated into the leaf. Drought significantly reduced the potential photosynthetic rate, stomatal conductance, SPAD, leaf area, and biomass production. Higher nitrogen applications with larger root system could support higher photosynthetic activities to accumulate more dry mass. Strong positive coefficient between photosynthetic and biomass nitrogen use efficiency and drought tolerance index may suggest that higher nitrogen use efficiency could help plants have higher ability to tolerate drought stress.     

浓香型烟叶成熟期质体色素的变化特征研究

为探明湖南浓香型烟叶质体色素在生育后期不同阶段和不同叶位间的差异,对云烟87在打顶期、打顶后10 d、打顶后20 d三个时期和上部、中部及下部叶三个叶位间的色素含量变化及叶绿素含量与SPAD值的关系进行了研究。结果表明：同一时期不同叶位叶绿素a、叶绿素b和总叶绿素含量都表现为：上部叶〉中部叶〉下部叶,除打顶期上部叶和中部叶差异不显著外,不同叶位差异达极显著水平;同一叶位不同时期叶绿素含量变化为,打顶期后下部叶逐步明显减少,中部叶先明显减少后少量增加,上部叶则先增加后降低。不同叶位类胡萝卜素的含量变化在同一时期都表现为：上部叶〉中部叶〉下部叶,且叶位间存在显著性差异。叶绿素a与叶绿素b含量比值和总叶绿素与类胡萝卜素比值在相同时期都表现为：上部叶〉中部叶〉下部叶,但前者在打顶期后呈逐渐降低趋势,后者则先增加后明显减少。上部叶、中部叶及下部叶的叶绿素含量均与相应SPAD值具有极显著正相关性。     

基于SPAD值的木薯叶绿素含量预测模型

为了探讨木薯叶绿素含量的非破坏性快速测定方法,在测量叶片SPAD值、比叶面积和叶绿素含量的基础上构建通过SPAD值预测总叶绿素含量的数学模型。结果表明,叶绿素a对于SPAD值的贡献率大于叶绿素b;比叶面积和叶位显著影响SPAD值与总叶绿素含量的关系,在SPAD值预测总叶绿素含量的模型中导入比叶面积和叶位2个自变量可提高预测总叶绿素含量的精度;基于SPAD值、比叶面积、叶位预测总叶绿素含量的模型为C=-4.51+0.092 5 Spv+0.039 9 Sa+0.145 0（Lp）。     

高产氮高效型粳稻品种的叶片光合及衰老特性研究

 选用6个具代表性的低产氮低效型、高产氮中效型和高产氮高效型粳稻品种,在各自最适氮素水平下,研究了叶片光合、衰老特性的差异及其与氮效率的关系。结果表明,高产类型群体叶面积指数(LAI)、高效叶面积率及有效叶面积率、剑叶叶绿素含量(SPAD值)和净光合速率以及剑叶超氧化物歧化酶(SOD)活性均显著高于低产类型品种,丙二醛(MDA)含量显著低于低产类型。高产品种间比较,随着氮效率提升,生育前中期(够苗、拔节、齐穗期)群体叶面积指数下降,成熟期上升;灌浆前期(齐穗后0 d~10 d)剑叶净光合速率并未明显变化,灌浆中后期(齐穗后20 d~40 d)显著增高,主要原因如下：叶绿素分解少,保证了叶片对CO2的高同化能力;SOD活性高,保证了植株更强的抗氧化能力,MDA含量少,膜脂破坏程度低。说明抽穗前合理控制无效及低效叶面积生长以适当减小群体叶面积规模,抽穗后有效延缓植株衰老,以保证叶片持续较高的叶绿素含量和净光合速率,是促进水稻高产品种进一步提升氮效率的重要途径。