土壤水分对柑橘叶片生长及多胺代谢的影响

本文以2年生宫川温州蜜柑(Citrus unshiu Marc.cv. Miyagawa Wase)盆栽幼树为材料,研究了土壤相对含水量(Soil Water Content,SWC)对橘叶生长和叶片多胺(腐胺Put,亚精胺Spd,精胺Spm)代谢的影响.结果表明:SWC由30%增加到90%,橘叶面积、叶周长、叶宽值均在75%时达最大值12.25 cm2、13.84 cm、3.19 cm,且叶面积、叶周长、叶长、叶宽均与SWC呈显著线性正相关;橘叶Put在SWC=75%时最低(228.95 nmol/g,FW),Spd和Spm均随土壤水分递增呈抛物线变化,其最大值分别出现在45%和60%.(Spd+Spm)/Put的比值与叶面积、叶周长、叶长、叶长/宽间呈显著或比较显著负相关,且当SWC≤75%时,此比值(t)与SWC(x)间呈显著正相关(t＝0.0112x + 0.173, p＜0.05).因此,(Spd+Spm)/Put比值可视为柑橘对土壤水分环境敏感度的指标之一.     

冬小麦叶面积动态变化规律及其定量化研究

通过田间试验,对冬小麦叶面积、比叶面积(SLA)及黄叶率(DR)予以描述和定量化,冬小麦冬后比叶面积与相对生育期(RDS)的对数呈线性递减关系,SLA=-21.07×ln(RDS)+19.427,最大和最小比叶面积分别为40m2/kg和19m2/kg.小麦黄叶率在冬后与相对生育期呈抛物线关系,可用下式表示DR=2.142×RDS2-1.8001×RDS+0 6571,这为冬小麦生长模型中的叶面积模拟提供了新的方法和理论依据.     

山地枣林蒸腾主要影响因子的时间尺度效应

为揭示时间尺度效应对蒸腾规律的影响,对黄土丘陵区山地枣林蒸腾及其影响因子进行同步监测,并在不同时间尺度上分析蒸腾的主要影响因子。结果表明:不论逐月蒸腾还是全年蒸腾,其主要影响因子均存在明显的时间变异性和时间尺度效应。逐月蒸腾在生育期内时、日和旬尺度上主要影响因子分别是光合有效辐射(R2峰值,Rmax2=0.79),风速(Rmax2=0.81)和相对湿度(Rmax2=0.78),叶面积(Rmax2=0.73)和叶面积指数(Rmax2=0.82)。全年蒸腾在较小时间尺度(时和日尺度)上和除风速外的其他气象因子均呈极显著相关(p0.01),而在较大尺度(旬和月尺度)上仅和叶面积、叶面积指数以及土壤水分呈极显著相关(p0.01)。随着研究尺度的提升,气象因子对蒸腾的影响逐渐减弱,作物自身生长状况和土壤水分状况对蒸腾的影响逐渐增强。该研究对于进一步揭示枣树的蒸腾规律,制定科学合理的节水措施具有重要的指导意义。     

高寒草甸非生长季土壤表层水汽传输阻抗的变化特征和水热驱动

土壤表层水汽传输阻抗是估算区域蒸散的关键参数之一,但其与土壤水热参数的数量关系的研究在高寒系统中十分薄弱。利用涡度相关系统观测的2014/2015年度高寒草甸非植被生长季(11月-翌年4月)的土壤蒸发数据,基于Penman-Monteith方程反推得出非生长季土壤表层阻抗的昼(9:00-18:00)变化特征,并研究其与土壤5cm温度和土壤5cm含水量的关系。结果表明,非生长季土壤表层阻抗表现出单峰型日变化特征,其最大值一般出现在15:00前后。逐时土壤表层阻抗与土壤5cm温度呈极显著幂函数阈值关系(R2=0.38,P0.01,N=115),即土壤温度为–4.25℃时土壤表层阻抗最大;与土壤5cm含水量呈极显著指数负相关(R2=0.12,P0.01,N=115)。非生长季逐日土壤表层阻抗的变化无明显季节规律,与土壤5cm温度(R2=0.69,P0.01,N=10)和土壤5cm含水量(R2=0.27,P0.01,N=10)均表现为极显著指数负相关。相关分析表明,非生长季土壤蒸发主要受太阳总辐射(R20.50,P0.01)的控制。研究结果表明土壤温度而非土壤含水量主导着高寒草甸非生长季土壤表层阻抗的变化。     

氮素营养对小麦群体光合碳同化作用的影响及其调控机制

小麦春季生育期间,群体光合速率(CPR)的动态变化呈单峰曲线,于孕穗至开花期达到最大值,不同氮素用量处理CPR的峰值大小、峰值出现时间和高值持续期不同。群体单位叶面积光合速率(CPR pa)与氮素用量呈显著负相关,高氮条件下CPR的提高主要起因于其群体叶面积的增大和冠层光截获率的增加。叶面积系数(LAI)随氮素用量增加呈逐渐增大趋势,但高氮处理生育后期LAI的衰减速率较快。CPR与同期及相邻生育时期的LAI呈显著正相关表明,CPR与LAI两者之间存在着相互制约关系。生育中后期 CPR 的日变化呈单峰曲线。不同氮素处理生育期间群体干物质的累积量与CPR的表现相似,CPR与同期及下一时期的群体干物质累积量成显著正相关。供试氮素范围内,整个春季生育阶段的群体叶源量(CKSC)随氮素用量增加呈抛物线型变化,施N 225kghm-2处理群体叶源量最高,与开花期CPR、开花 蜡熟CKSC和同期CPR及LAI衰减速率的表现趋势相同。表明提高生育后期的群体光合速率,延长其高值持续时间,对于增加整个春季生育阶段的群体碳同化量具有重要作用。     

基于LAI测试的精确人造果树模型

精确人造果树为叶面积指数LAI和生物量测试提供固定、标准的参数,能避免真树受环境时空变化而参数改变的弊端。通过3D数字化仪（Polhemus Fastrak）采集真树的坐标（枝叶的位置、方向等空间结构参数）,用独特的工艺,进行人造树模型的构建。根据多种方法的对照（图片、三维可视化、坐标误差分析）进行了经过多次、长时间多阶段（粗调、微调和整体精调3个阶段）的枝、干、叶调试,以达到仿真的效果。利用虚拟果树技术,与真树坐标、高度、叶面积、投影面积分布进行对比分析,人造树高度－累积叶面积（LAI）线性回归的决定系数R2为0.9892,人造树阴影面积－叶累积面积线性回归的决定系数R2为0.9973。人造树与真树轮廓外观尺寸相对误差在小于3%,叶子坐标误差服从正态分布。真树-人造树随高度变化的投影面积累积面积误差小于5%,累积投影面积误差为20%,它们在高度为0～65 cm范围段稳定。     

氮素营养对小麦群体光合碳同化作用的影响及其调控机制

小麦春季生育期间,群体光合速率(CPR)的动态变化呈单峰曲线,于孕穗至开花期达到最大值,不同氮素用量处理CPR的峰值大小、峰值出现时间和高值持续期不同。群体单位叶面积光合速率(CPR pa)与氮素用量呈显著负相关,高氮条件下CPR的提高主要起因于其群体叶面积的增大和冠层光截获率的增加。叶面积系数(LAI)随氮素用量增加呈逐渐增大趋势,但高氮处理生育后期LAI的衰减速率较快。CPR与同期及相邻生育时期的LAI呈显著正相关表明,CPR与LAI两者之间存在着相互制约关系。生育中后期 CPR 的日变化呈单峰曲线。不同氮素处理生育期间群体干物质的累积量与CPR的表现相似,CPR与同期及下一时期的群体干物质累积量成显著正相关。供试氮素范围内,整个春季生育阶段的群体叶源量(CKSC)随氮素用量增加呈抛物线型变化,施N 225kg·hm^-2处理群体叶源量最高,与开花期CPR、开花 蜡熟CKSC和同期CPR及LAI衰减速率的表现趋势相同。表明提高生育后期的群体光合速率,延长其高值持续时间,对于增加整个春季生育阶段的群体碳同化量具有重要作用。     

水肥供应对番茄果实维生素C含量的影响

采用四元二次正交旋转组合设计,通过番茄盆栽试验,研究灌水量和氮、磷、钾肥用量对番茄维生素C含量的影响。结果表明,在试验条件下,番茄果实中维生素C含量随灌水量和施磷量呈开口向下的抛物线型变化,随钾肥用量呈开口向上的抛物线型变化,但不受氮肥用量的影响;交互效应表现为灌水量和施磷量以及施氮量和施钾量均呈负交互作用。表明合理的灌水量、施磷量和施钾量有利于提高番茄果实中的维生素C含量,而施氮量的改变是通过与施钾量发生负交互作用抑制番茄维生素C累积的。     

砂粒含量对土壤水分蓄持能力影响模拟试验研究

通过人工配制不同质地土壤,测定土壤水分特征曲线,研究了土壤中砂粒含量对其水分蓄持能力的定量影响.结果表明:(1)砂粒含量对土壤水分蓄持能力有较大影响.土壤持水能力随砂粒含量增加递减,表征土壤持水能力的水分特征曲线Gardner模型参数及表征土壤饱和含水量的Van Genuchten模型参数均随砂粒含量增加逐渐减小.(2)砂粒含量对土壤比水容量有较大影响,试验土壤在任一吸力水平下的比水容量值均随其砂粒含量增加递减.(3)试验土壤饱和含水量与砂粒含量呈线性关系,田间持水量、凋菱系数与砂粒含量都呈开口向下抛物线右半段的关系.(4)试验土壤有效水、迟效水含量随砂粒含量增加递减,二者与砂粒含量均呈开口向下抛物线右半段的关系.易效水含量与砂粒含量呈开口向上抛物线关系.     

温室黄瓜叶面积扩展与光合特性对土壤水分的响应研究

温室盆栽试验研究土壤水分对黄瓜叶面积扩展与光合特性的影响结果表明,黄瓜叶片扩展经历了指数生长(EG)、线性生长(LSG)和稳定生长(SCG)3个阶段。随土壤含水量的增加,叶面积(LA)显著增大,叶片生长速率(LGR)的最大值明显提前。叶片相对扩展速率(RER)在指数生长阶段迅速增加,但在线性生长和稳定生长阶段则逐渐减小。土壤含水量显著影响了叶片的扩展和光合特性。叶片生长进程中,叶绿素含量和净光合速率(Pn)逐渐增加,处理间差异明显,不同水分处理的叶片净光合速率日变化均表现为单峰曲线,其表观量子效率(AQY)、羧化效率(CE)具有显著差异。     

21000-2300nm波段的小麦冠层光谱特性与叶面积指数和叶片氮含量间的关系及其受叶片水分含量的影响

The effects of leaf water status in a wheat canopy on the accuracy of estimating leaf area index （LAI） and N were determined in this study using extracted spectral characteristics in the 2 000-2 300 nm region of the short wave infrared （SWI） band. A newly defined spectral index, relative adsorptive index in the 2 000-2 300 nm region （RAI2000-2300）, which can be calculated by RAI2000-2300 = （R2224 - R2054） （R2224 ＋ R2054）-1 with R being the reflectance at 2 224 or 2 054 nm, was utilized. This spectral index, RAI2000-2300, was significantly correlated （P 〈 0.01） with green LAI and leaf N concentration and proved to be potentially valuable for monitoring plant green LAI and leaf N at the field canopy scale. Moreover, plant LAI could be monitored more easily and more successfully than plant leaf N. The study also showed that leaf water had a strong masking effect on the 2 000-2 300 nm spectral characteristics and both the coefficient between RAI2000-2300 and green LAI and that between RAI2000-2300 and leaf N content decreased as leaf water content increased.     

不同类型园林植物群落冠层的截留能力研究

[目的] 对不同类型园林植物群落冠层截留能力进行研究,为选择冠层截留效果最优的植物群落配置提供理论依据。[方法] 选取7种不同结构的植物群落采用实测法分别测定林外降雨量、林下穿透雨量、树干茎流量,再利用水量平衡法求得冠层截留量,进行分析对比。[结果] 单层针阔混交林的冠层截留率达到了49.86%,截留效果最好。单层阔叶灌木截留率为23.66%,截留效果最差。林外降雨量与林下穿透雨量、树干茎流量、冠层截留量呈线性正相关,拟合系数R²均在0.9左右。对冠层特性与冠层截留能力进行相关性分析的结果为,叶面积指数、郁闭度、冠层厚度、绿化覆盖面积和三维绿量与穿透率呈负相关,与截留率呈正相关。[结论] 园林植物群落冠层对雨水有一定的截留能力,且不同类型的群落有一定的差异性,单层阔叶灌木的截留率最低,单层针阔混交林的截留率最高;叶面积指数与郁闭度越高、冠层越厚、绿化覆盖面积与三维绿量越大,园林植物群落的冠层截留能力越好。     

Specific Leaf Area and Specific Leaf Weight in Small Grain Crops Wheat,Rye, Barley,and Oats Differ at Various Growth Stages and NPK Source

Leaf thickness plays an important role in leaf and plant functioning and is related to species’ strategies of resource acquisition and use. Leaf thickness in small grains crops was measured as specific leaf area (SLA) (leaf area in cm² produced g^?1 leaf dry weight plant^?1) and specific leaf weight (SLW) (leaf dry weight in mg produced cm^?2 leaf area plant^?1). The four small grains crops (cool season C₃ cereals) studied were wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.) and oats (Avena sativa L.). The null hypothesis tested was that SLA and SLW in small grain crops do not differ at different growth stages and nitrogen, phosphorus, and potassium (NPK) source. Eight NPK sources used in the experiment were: S₁ = 20-20-20, S₂ = 20-27-5, S₃ = 7-22-8, S₄ = 10-10-10-20S, S₅ = 11-15-11, S₆ = 31-11-11, S₇ = 24-8-16, and S₈ = 19-6-12, and each was applied at the rate of 300 mg pot^?1 at the time of sowing to each crop species. The experiment was performed in completely randomized design with three repeats at the Green House of Dryland Agriculture Institute, West Texas A&M University, Texas, during winter 2009-10. Based on the results, it was observed that both SLA and SLW differed with change in crop species, growth stage and NPK source. Among the crop species, SLA was greater in oats > barley > rye > wheat at different growth stages; while SLW of wheat and rye > barley and oats. The differences in the SLW between wheat vs. rye; and between oats vs. barley at different growth stages were not significant (P ≤ 0.05). Among the NPK sources, application of S₇ (24: 8: 16) had higher SLA at 60 and 90 DAE (days after emergence). Application of S₆ (31: 11: 11) had higher SLW at 60 DAE due to the production of the lowest leaf area plant^?1, but the increase in SLW at 90 DAE with S₅ and S₄ was due to the higher leaf dry weight plant^?1produced. Leaf dry weight and leaf area plant^?1 were considered the two most important leaf characteristics that influenced SLA and SLW. On the average, SLA increased with passage of time i.e. 0.70 < 520 < 600 cm² g^?1 at 30, 60 and 90 DAE, respectively; but SLW on the other hand, was highest 3.5 at 60 DAE > 2.2 at 90 DAE > 1.5 mg cm^?2 at 30 DAE. The increase in leaf area plant^?1 and decline in the leaf dry weight plant^?1 increased SLA; in contrast, increase in leaf dry weight plant^?1 and reduction in leaf area plant^?1 increased SLW indicated reciprocal relationship between SLA and SLW in the crop species.     

Cultivation of potato – use of plastic mulch and row covers on soil temperature,growth, nutrient status,and yield

Potato is one of the most important crops in the world because of its high nutritional value; however, traditional cultivation in bare soil may render low yields and poor quality. Crop production efficiency can be increased by using plastic mulching and row covers to modify root zone temperature and plant growth, in addition to reduction in pest damage and enhance production in cultivated plants. However, there is little information demonstrating the effect of row covers in combination with plastic mulch on potato. The aim of this study was to assess the change in root zone temperature and its effect on growth, leaf nutrient, and yield of potato using plastic mulch of different colors, in combination with row covers. Seed of cultivar Mondial was planted in May 2012. The study included four plastic films: black, white/black, silver/black, aluminum/black, and a control with bare soil, which were evaluated alone and in combination with row covers removed at 30 days after sowing in a split-plot design. Higher yields were obtained when no row cover (43.2 t ha^?1) and the white/black film (42.2 t ha^?1) were used. Leaf nitrogen, sulfur, and manganese concentration were higher in plants when row cover was used; in contrast, no–row cover plants were higher in Fe and Zn. Mulched plants were higher in Mn concentration than control plants. There was a quadratic relationship between mean soil temperature and total yield (R² = 0.94), and between plant biomass and total yield (R² = 0.98), between leaf area with total yield (R² = 0.98).     

Development of the Nondestructive Leaf Area Estimation Model for Valeriana (Valeriana jatamansi Jones)

Leaf area (LA) is an important parameter related to plant growth and physiology. An allometric model was developed to estimate the LA of endangered medicinal plant Valeriana jatamansi using linear measurements such as leaf length (L) and width (W). LA and other leaf dimensions were measured using a laser leaf area meter. Leaves from seven accessions of valeriana were collected from the experimental site during 2015. Different regression models were developed between LA and other leaf components, viz. L, W, etc. The linear model having LW as an independent variable (y = 0.487 + 0.644 LW) provided the best estimation [coefficients of determination (R²) = 0.974, root mean square error (RMSE) = 2.222, coefficient of variation (CV) = 4.529]. Validation of the selected model showed a higher correlation between the actual leaf area (ALA) and the predicted leaf area (PLA) [R² = 0.956, RMSE = 2.310, CV = 5.319, predicted residual error sum of squares (PRESS) = 1067.352].     

Growth,Chlorophyll, and Cation Concentration of Tetraploid Wheat on a Solution High in Sodium Chloride Salt: Hulled Versus Free-Threshing Genotypes

Based on the literature, under-utilized hulled wheats could be tolerant to some harsh environmental conditions. The effect of salt stress on chlorophyll content, leaf area, dry weight, and ion concentrations in eight genotypes of tetraploid wheat (Triticum turgidum) using a three-replicate completely random design indoor experiment was studied. These genotypes included six hulled wheat (HW), T. turgidum subspp. Dicoccum, and two free-threshing wheat (FTW), T. turgidum subspp. durum. Salt stress was induced by adding sodium chloride (NaCl) to a hydroponic medium to 40, 80, and 120 mM, in addition to control. Salinity reduced leaf content of chlorophyll a (chl-a) at 120 mM but had not significant effect on chlorophyll b (chl-b) content. Salt stress decreased plant leaf area by nearly 63%. Plant top dry weight declined by 52% with increasing salinity to 120 mM level. Plant top calcium (Ca²⁺) content was not affected, whereas plant top sodium (Na⁺) concentration increased and potassium (K⁺) and magnesium (Mg⁺) concentration decreased with increasing salinity, averaged over genotypes. No significant interaction of genotype × salinity was detected for traits studied in this experiment. When contrasted as two groups of genotypes, i.e., HW vs. FTW, the former group suffered more severe decreases in terms of chl-a, chl-b, leaf area, dry weight, and Mg²⁺ concentration and a more pronounced increase in Na⁺ compared to the FTW. Overall, no evidence of salt tolerance was found for hulled tetraploid wheats of central Iran.     

Non-destructive estimation of sunflower leaf area and leaf area index under different water regime managements

Leaf area (LA) is a valuable parameter in many agronomic and plant physiological studies. Its measurement is time consuming and involves leaf destruction. Therefore, there is a tendency in using simple, fast, non-destructive, and electronic devices methods to estimate LA. The aim of this study was to estimate LA across different water regime treatments using a combination of leaf mass and leaf dimensions of sunflower (Helianthus annuus L.). For this purpose, different leaf sizes were collected from plants during the growing season on different time intervals. Experiment was conducted during 2012 summer time in Sari Agriculture Sciences and Natural Resources University, Iran. On field leaf dimension measurements were carried out, and leaves sketches were put on paper, scanned and then areas were measured using AutoCAD software. Multivariate linear and non-linear regression models were constructed between LA and other leaf components measured. All constructed models provided highly significant correlations (r = 0.90–0.99) between LA and different leaf components. The exponential model [LA = 0.619 [(L × W)^0.5]^2.019] provided the best estimation of sunflower LA (R² = 0.993). In conclusion, the simple and quick models developed in this study could predict the sunflower LA and leaf area index (LAI) with high precision.     

Effects of Biozyme (Ascophyllum nodosum) Biostimulant on Growth and Development of Soybean [Glycine Max (L.) Merill]

Field experiment was conducted to investigate the effects of Biozyme^TM on soybean. Application of Biozyme granule and crop-plus spray with half of recommended nitrogen, phosphorus, and potassium (NPK) showed significant effects on all the growth and yield parameters of soybean. The greatest value for the number of trifoliate leaves (29.95 leaves plant^?1), leaf area (1818.21 cm2 plant^?1), leaf area index (5.946), total chlorophyll content (1.995 mg g^?1 leaf fresh mass), number of nodules (35.086 plants^?1), fresh and dry weight of nodules (0.664 and 0.1592 g plants^?1), dry weight of root (8.564 g plants^?1), pods plant^?1 (69.0), seeds pods^?1 (3.25), straw yield (3.122 t ha^?1), biological yield (6.349 t ha^?1), and grain yield (3.277 t ha^?1) was observed with Biozyme crop-plus spray at 500 mL ha^?1 plus half of recommended NPK and were significantly greater than control values. Biozyme crop-plus spray at 500 mL ha^?1 plus half of recommended NPK performed better compared to other treatments.     

Evaluation of Drip-Irrigated Cotton Grown under Different Plant Population Densities and Two Irrigation Regimes

Modification of plant population density and irrigation regime may impact seed cotton and lint yield, fiber quality, photosynthesis, and nitrogen uptake, especially in areas with severe water shortages and limited water resources. Furthermore, it reduces seeds and other agricultural practices costs without sacrificing yield. Field experiments examining the impact of plant population and irrigation regime on cotton growth, cotton yield parameters, fiber quality, leaf area, and chlorophyll content of cotton leaves were conducted in the city of Aleppo, northern Syria, in 2004 and 2005. Plant populations of 74,000, 57,000, 48,000, 41,000, and 33,500 plants ha^?1 and two drip irrigation regimes [one planting row/one irrigation line (one/one) and two planting rows/one irrigation line (two/one)] were tested. Cotton was planted in April 2004 and 2005 at the Agricultural Research Center in northern Syria on a Chromoxerertic Rhodoxeralf soil. Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as indicated by the neutron probe. Before all plots were hand-picked each year, a 20-lint sample was collected per plot and sent to the Cotton Research Administration Laboratory for fiber quality analysis. Seed cotton yields were lowest with populations of 33,500 plants ha^?1 compared to the other tested population densities. However, the other plant densities did not much influence seed cotton yield, fiber quality, leaf area, and leaf chlorophyll content. Water savings for different plant densities grown under the one/one irrigation regime ranged between 11.2 and 38.3% of irrigation water relative to two/one irrigation regime. Reducing population densities up to 41,000 plants ha^?1 and adapting a one/one irrigation regime appear to be viable cost-saving options.     

机器学习结合高光谱植被指数与SPAD值估算冬小麦氮含量

冬小麦叶片氮含量与叶片光合作用和营养状况密切相关,直接影响植株生长发育,而茎秆中的氮含量与茎秆中纤维素、半纤维素和木质素的比例和含量密切相关,直接影响茎秆质量及植株的抗倒伏能力。然而,有关对冬小麦茎秆氮含量估算研究较为有限,限制了从氮含量角度判断茎秆质量及对倒伏的预测能力。为精准估算冬小麦不同器官（叶片、茎秆）氮含量,该研究通过2年田间试验,获取冬小麦4个关键生育期（拔节期、抽穗期、开花期、灌浆期）和3种施氮水平条件下（N1、N2和N3）的冠层光谱反射率、叶片、茎秆氮含量及叶片SPAD (soil and plant analyzer development, SPAD)值。分析了不同生育期和施氮水平条件下高光谱植被指数对叶片和茎秆氮含量的敏感性,并结合5种常用的机器学习算法：随机森林回归（random forest regression,RFR）、支持向量回归（support vector regression,SVR）、偏最小二乘回归（partial least squares regression,PLSR）、高斯过程回归（gaussian process regression,GPR）、深度神经网络回归（deep neural networks,DNN）构建冬小麦叶片和茎秆氮含量估算模型。结果表明：高光谱植被指数对叶片和茎秆氮含量的敏感性受到生育期和施氮水平的影响。在灌浆期,最佳植被指数双峰冠层植被指数 DCNI（double-peak canopy nitrogen index）对叶片氮含量的敏感性最高,R²为0.866。对茎秆氮含量,在抽穗期的敏感性最高,最佳植被指数归一化叶绿素比值指数 NPQI（normalized phaeophytinization index）与氮含量相关系数R²＝0.677。施氮水平的提升增加了光谱植被指数对茎秆氮含量的敏感性。结合SPAD值的机器学习算法提升了氮含量的估算精度,对叶片氮含量,在不同生育期和施氮水平条件下估算精度提升了1%～7%,其中在全生育期的归一化均方根误差NRMSE从0.254提升到0.214,抽穗期的NRMSE提升最大,从0.201提升到0.128。对茎秆氮含量,全生育期的NRMSE从0.443提升到0.400,抽穗期的NRMSE提升最大,从0.323提升到0.268。在全生育期,结合SPAD值的DNN模型对叶片（R²=0.782、NRMSE=0.214）和茎秆（R²=0.802、NRMSE=0.400）氮含量的估算精度最佳。研究说明,SPAD值与光谱植被指数结合有利于提升冬小麦不同生育期和施氮水平条件下叶片和茎秆氮含量的估算精度。