A bHLH transcription factor,CsSPT,regulates high-temperature resistance in cucumber

High-temperature stress threatens the growth and yield of crops. Basic helix-loop-helix(bHLH) transcription factors(TFs) have been shown to play important roles in regulating high-temperature resistance in plants. However, the bHLH TFs responsible for high-temperature tolerance in cucumbers have not been identified. We used transcriptome profiling to screen the high temperature-responsive candidate bHLH TFs in cucumber. Here, we found that the expression of 75 CsbHLH genes was altered under high-temperature stress. The expression of the CsSPT gene was induced by high temperatures in TT(Thermotolerant) cucumber plants. However, the Csspt mutant plants obtained by the CRISPR-Cas9 system showed severe thermosensitive symptoms, including wilted leaves with brown margins and reduced root density and cell activity.The Csspt mutant plants also exhibited elevated H_(2)O_(2) levels and down-regulated photosystem-related genes under normal conditions.Furthermore, there were high relative electrolytic leakage(REC), malondialdehyde(MDA), glutathione(GSH), and superoxide radical(O_(2)^(·-)) levels in the Csspt mutant plants, with decreased Proline content after the high-temperature treatment. Transcriptome analysis showed that the photosystem and chloroplast activities in Csspt mutant plants were extremely disrupted by the high-temperature stress compared with wildtype(WT) plants. Moreover, the plant hormone signal transduction, as well as MAPK and calcium signaling pathways were activated in Csspt mutant plants under high-temperature stress. The HSF and HSP family genes shared the same upregulated expression patterns in Csspt and WT plants under high-temperature conditions. However, most bHLH, NAC, and bZIP family genes were significantly down-regulated by heat in Csspt mutant plants. Thus, these results demonstrated that CsSPT regulated the high-temperature response by recruiting photosynthesis components, signaling pathway molecules, and transcription factors. Our results provide important insights into the heat response mechanism of CsSPT in cucumber and its potential as a target for breeding heat-resistant crops.

Study on Photosynthesis of Different Position Leaves of Cucumber in Solar-Greenhouse

The photosynthetic rate (Pn) and carboxylation efficiency (CE) were observed to be the highest in mid-position leaves of cucumber in solar-greenhouse, second in upper and middle-lower position leaves, and lowest in lower-position leaves. The saturation light of the mid-position leaves was also the highest, while the photo compensation points of the upper, middle and lower position leaves decreased as the leaf-position descended. During the growth period, the Pn of most leaves enhanced as PFD increased. Pn curves of diurnal variation in different position leaves had single-peak which appeared at 12: 00 a. m. As the plant density increased, the PFD of different layer leaves decreased, especially of the lower position leaves. The effect of plant density on the Pn of the upper-position leaves was not visible, but on the light compensation points was obvious. As to lower position leaves, the Pn and saturation light decreased as the plant density increased, but the light compensation points were not obviously affected. Cucumber leaves had certain capacity of adaptation and adjustment to light intensity which expressed as the lower the PFD, the higher the apparent quantum yield (AQY). So the AQY increased as the leaf position descended and plant density increased.

Effects of Exogenous Silicon on Photosynthetic Capacity and Antioxidant Enzyme Activities in Chloroplast of Cucumber Seedlings Under Excess Manganese

Effects of silicon on photosynthetic parameters and antioxidant enzymes of chloroplast in cucumber seedlings under excess Mn were studied. Compared with the control, excess Mn significantly inhibited net photosynthetic rate （Pn）, stomatal conductance, as well as the maximum yield of the photosystem II photochemical reactions （Fv/Fm） and the quantum yield of photosysytem II electron transport （Φ PSII）, application of Si reversed the negative effects of excess Mn. In the further investigation, it was obtained that application of Si significantly increased the activities of enzymes related with ascorbate-glutathione cycle including ascorbate peroxidase （APX）, dehydroascorbate reductase （DHAR） and glutathione reductase （GR） in cucumber chloroplast under excess Mn, this could be responsible for the lower accumulation of H2O2 and lower lipid peroxidation of chloroplast induced by Mn, and resulted in keeping higher photosynthesis.

The effect of artificial solar spectrum on growth of cucumber and lettuce under controlled environment

Light-emitting diodes(LEDs)have been widely applied in the controlled environment agriculture,which are characterized by relatively narrow-band spectra and energetical efficiency.Most recently,the spectrum of Sunlike LEDs has been engineered and it closely resembles solar spectrum in the range of photosynthetic active radiation(PAR,400–700 nm).To investigate how plant growth responses to the spectrum of Sunlike LEDs,cucumber and lettuce plants were cultivated and their responses were compared with the conventional white LEDs as well as composite of red and blue LEDs(RB,R/B ratio was 9:1).We observed that although Sunlike LEDs resulted in a longer stem in cucumber,dry weight and leaf area were similar as those under RB LEDs,and significantly higher than those under white LEDs.Moreover,cucumber leaves grown under Sunlike and white LEDs showed higher photosynthetic capacity than those grown under RB LEDs.For lettuce,plants grown under Sunlike LEDs showed larger leaf area and higher dry weight than the other two treatments.However,the leaf photosynthetic capacity of lettuce grown under Sunlike LEDs was the lowest.In this context,the spectrum induced plant functions are species-dependent.Furthermore,the three types of LEDs show distinct light spectra and they are different in many aspects.Therefore,it is difficult to attribute the different plant responses to certain specific light spectra.We conclude that plants grown under Sunlike LEDs exhibit larger leaf area,which may be due to some specific spectrum distributions(such as more far-red radiation),and consequently are favorable for light interception and therefore result in greater production.

Effects of Elevated CO 2 and High Temperature on Single Leaf and Canopy Photosynthesis of Rice

The increase of atmospheric CO 2 concentration is indisputable. In such condition, photosynthetic response of leaf is relatively well studied, while the comparison of that between single leaf and whole canopy is less emphasized. The stimulation of elevated CO 2 on canopy photosynthesis may be different from that on single leaf level. In this study, leaf and canopy photosynthesis of rice (Oryza sativa L.) were studied throughout the growing season. High CO 2 and temperature had a synergetic stimulation on single leaf photosynthetic rate until grain filling. Photosynthesis of leaf was stimulated by high CO 2, although the stimulation was decreased by higher temperature at grain filling stage. On the other hand, the simulation of elevated CO 2 on canopy photosynthesis leveled off with time. Stimulation at canopy level disappeared by grain filling stage in both temperature treatments. Green leaf area index was not significantly affected by CO 2 at maturity, but greater in plants grown at higher temperature. Leaf nitrogen content decreased with the increase of CO 2 concentration although it was not statistically significant at maturity. Canopy respiration rate increased at flowering stage indicating higher carbon loss. Shading effect caused by leaf development reached maximum at flowering stage. The CO 2 stimulation on photosynthesis was greater in single leaf than in canopy. Since enhanced CO 2 significantly increased biomass of rice stems and panicles, increase in canopy respiration caused diminishment of CO 2 stimulation in canopy net photosynthesis. Leaf nitrogen in the canopy level decreased with CO 2 concentration and may eventually hasten CO 2 stimulation on canopy photosynthesis. Early senescence of canopy leaves in high CO 2 is also a possible cause.

Effect of the L-D_(1)alleles on leaf morphology,canopy structure and photosynthetic productivity in upland cotton(Gossypium hirsutum L.)

One of the most important objectives for breeders is to develop high-yield cultivars.The increase in crop yield has met with bottlenecks after the first green revolution,and more recent efforts have been focusing on achieving high photosynthetic efficiency traits in order to enhance the yield.Leaf shape is a significant agronomic trait of upland cotton that affects plant and canopy architecture,yield,and other production attributes.The major leaf shape types,including normal,sub-okra,okra,and super-okra,with varying levels of lobe severity,are controlled by a multiple allelic series of the D-genome locus L-D_(1).To analyze the effects of L-D_(1)alleles on leaf morphology,photosynthetic related traits and yield of cotton,two sets of near isogenic lines(NILs)with different alleles were constructed in Lumianyan 22(LMY22)and Lumianyan 28(LMY28)backgrounds.The analysis of morphological parameters and the results of virus-induced gene silencing(VIGS)showed that the regulation of leaf shape by L-D_(1)alleles was similar to a gene-dosage effect.Compared with the normal leaf,deeper lobes of the sub-okra leaf improved plant canopy structure by decreasing the leaf area index(LAI)and increasing the light transmittance rate(LTR),and the mid-range LAI of sub-okra leaf also guaranteed the accumulation of cotton biomass.Although the chlorophyll content(SPAD)of sub-okra leaf was lower than those of the other two leaf shapes,the net photosynthetic rate(Pn)of sub-okra leaf was higher than those of okra leaf and normal leaf at most stages.Thus,the improvements in canopy structure,as well as photosynthetic and physiological characteristics,contributed to optimizing the light environment,thereby increasing the total biomass and yield in the lines with a sub-okra leaf shape.Our results suggest that the sub-okra leaf may have practical application in cultivating varieties,and could enhance sustainable and profitable cotton production.

Canopy Net Photosynthesis Rate of a Mongolian Oak (<i>Quercus mongolica</i>) Forest Estimated by Field Experimental Data

The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the Nam-San site in Seoul, Korea for the growing period from early May to late October in 2010. The empirical models include the attenuation function of photosynthetic photon flux density (PPFD) (r2 = 0.98-0.99, p r2 = 0.99, p < 0.001) derived from the measured data at several levels within the canopy. The incident PPFD at each level within canopy significantly varies diurnally and seasonally due to the seasonal variation of the total plant area index (TPAI = leaf area index + wood silhouette area index) and the light shielding effect of light path-length through the canopy in association with the variation of solar elevation angle. Consequently, a remarkable seasonal variation of the total canopy net photosynthesis rate of Q. mongolica forest stand is found for its growing period. The PPFD exceeding 1000 μmol m-2·s-1 is found to cause the decrease of net photosynthesis rate due to the thermal stress in the early (May) and late (September) growing period. During the whole growing season, the estimated total canopy net photosynthesis rate is found to be about 3.3 kg CO2 m-2.

Image segmentation algorithm for greenhouse cucumber canopy under various natural lighting conditions

In this study,machine vision technology was used to capture images of greenhouse cucumber canopy,and image segmentation was implemented under various natural lighting conditions.The images were enhanced by multi-scale retinex with color restore(MSRCR),and the MSRCR images were segmented by four algorithms:normalized difference index(NDI),excess green(ExG),modified excess green(MExG),and modified excess green minus excess red(MExG-ExR).The results indicated that compared with the original images,under various lighting conditions,the average evaluation indexes of brightness,information entropy,average gradient and mean gray value of the MSRCR images were increased by 38.71%,8.04%,4.54%,and 37.81%,respectively,and only the contrast degree decreased by 12.13%.The MExG-ExR segmentation algorithm was used to segment the MSRCR images(fifty images under various lighting conditions in the test and it performed best among the four segmentation algorithms,average overlap ratios and recognition rates of were 99.28%and 98.91%,respectively,while 38.39%and 37.95%respectively for original image.These results indicated that the MExG-ExR segmentation algorithm applied to a MSRCR canopy image produced the most stable results among the four algorithms.By using the MSRCR image enhancement algorithm,the interference of lighting on greenhouse cucumber canopy images was reduced and the foundation for achieving accurate segmentation of a canopy region was laid,which is of great significance for greenhouse cucumber phenotypic parameter measurements.

Growth of cucumber seedlings in different varieties as affected by light environment

High-quality cucumber seedlings are a prerequisite for ensuring high yield of cucumbers.With the continuous increase of cucumber planting area in China,the demand for high-quality cucumber seedlings is also increasing.One of the important ways to improve the quality of cucumber seedlings is to improve the light environment by using artificial light source.In this study,three cucumber seedlings(cv.Jintong,cv.Yunv and cv.Xiazhiguang)were grown for 23 d under eight levels of daily light integral(DLI)at 4.3 mol/(m^(2)·d),8.6 mol/(m^(2)·d),10.1 mol/(m^(2)·d),13.0 mol/(m^(2)·d),5.8 mol/(m^(2)·d),11.5 mol/(m^(2)·d),14.4 mol/(m^(2)·d)and 17.3 mol/(m^(2)·d),respectively.The results showed that when DLI was 14.4 mol/(m^(2)·d),the seedling height,stem diameter,total leaf area and shoot dry/fresh weight of all three cucumber cultivars reached the maximum,while hypocotyl length decreased with the increase of light intensity.When DLI was 14.4 mol/(m^(2)·d),Jintong and Xiazhiguang had the highest health index,which were 49.29 and 28.56,respectively,while that of Yunv was 81.59(DLI=14.4 mol/(m^(2)·d)).With the increase of DLI,the photosynthetic capacity of cucumber increases gradually.The highest net photosynthetic rate was shown at DLI of 14.4 mol/(m^(2)·d),while the chlorophyll content of cucumber seedlings of all three cultivars were less affected by DLI.Jintong and Yunv had the highest chlorophyll content when DLI was 8.6 mol/(m^(2)·d)because they were adapted to low-light environment.In conclusion,the DLI of 14.4 mol/(m^(2)·d)for Jintong and Xiazhiguang,while that of 17.3 mol/(m^(2)·d)for Yunv are suggested for the light environment design of factory-cultivated seedling for cucumber.

Influences of open-central canopy on photosynthetic parameters and fruit quality of apples(Malus×domestica)in the Loess Plateau of China

Although open-central canopy(OCC)is popular in apple(Malus×domestica)orchards in Loess Plateau of China,its relevant photosynthetic mechanisms have not been elucidated.In this study,changes in photosynthetically active radiation(PAR),gas exchange,chlorophyll fluorescence quenching and fruit quality in apple trees were measured in OCC and compared with those in the conventional condensed round and large canopy(RLC).Results showed that light intercepted at different orientations was 44%higher by OCC than that by RLC.The improved light environment within OCC remarkably increased leaf maximum net photosynthetic rate(Pnmax)and significantly decreased stomatal limitation.Under high light,the ratio of photorespiratory rate to gross photosynthetic rate(Pr/Pg)in OCC was higher than that in RLC.Moreover,reversible component in non-photochemical quenching(r(qE))was increased,while irreversible component(r(qI))was decreased in OCC than in RLC.As a result,the fruit quality in OCC was greatly boosted as evidenced by the significantly increased single fruit weight,fruit flesh firmness and fruit soluble solid contents and the sharply decreased fruit titratable acid contents.PAR intercepted by the canopy and the fruit soluble solid contents,leaf Pnmaxor single fruit weight were positively correlated,while PAR or Pnmaxwas negatively correlated with the fruit titratable acid contents.Accordingly,the improved crown light environment and the enhanced leaf photosynthetic performance and photoprotective capacity in OCC led to the boosted fruit quality.

水钾复合处理对越夏基质培黄瓜秧苗形态及生理指标的影响

黄瓜(Cucumis sativus L.)是设施农业中种植面积最大的蔬菜种类之一,同时也是耗水量较大的蔬菜作物,世界范围的干旱问题日趋严重,水分的缺失使得大量的肥料不能被植物吸收利用,因而植株会出现各种缺肥症状。合理的水肥供应是作物高产高效的生产基础。本试验研究了3种灌溉下限(W60:基质田间持水量的60%;W70:基质田间持水量的70%;W80:基质田间持水量的80%)和3种施钾量(K0:0 mmol/L;K4:4 mmol/L;K8:8 mmol/L)对夏季高温期温室内种植的黄瓜营养生长期的生长发育、叶片光合特性、植株根系指标和植株生物量的影响。结果表明:W70K8处理更好的促进了黄瓜的生长,使其株高、茎粗、叶片数、节间长度和叶面积生长指标显著的增加。W70K8处理可以显著提高黄瓜叶片的叶绿素含量,叶绿素a、叶绿素b和类胡萝卜素含量均为最高。W70K8处理的黄瓜叶片净光合速率最高,为18.36μmol/(m^(2)·s)。W70K8处理显著促进了黄瓜的根系活力,根系活力为88.24μg TTF/(g·h)。综上,W70K8处理可以提高基质栽培黄瓜营养生长期的叶绿素含量、净光合速率、和各项生长指标,促进黄瓜生长发育。试验表明,在夏季设施基质栽培黄瓜营养生长期的适宜水钾耦合模式为:灌溉下限为基质田间持水量的70%,施钾浓度为8 mmol/L。

基于冠气温差的温室黄瓜蒸散量模拟

通过建立基于不同时刻冠气温差(T c-T a)的温室黄瓜日蒸散量(ET c)估算模型,分析了基于不同时刻T c-T a对估算ET c的准确性;同时,基于T c-T a构建了估算黄瓜不同生育期ET c的Jackson模型,并将模型估算结果与基于冠层阻力参数(r c)的Penman-Monteith模型及蒸渗仪实测数据进行比较,结果显示,基于14:00的T c-T a构建的Jackson模型,估算温室黄瓜ET c的精确度最高(R 2为0.937),误差最小(RMSE为0.722 mm/d);相比Penman-Monteith模型(R 2为0.964),基于T c-T a的Jackson经验模型对黄瓜ET c估算结果与实测值相关性更高(R 2为0.967),误差更小(RMSE为0.735 mm/d).研究结果可为温室ET c模拟以及节水灌溉智能决策提供科学依据.

基于阈值识别的温室黄瓜整体自动落蔓装置研究

针对长季节黄瓜作物人工落蔓强度大、成本高和效率低等问题,设计一种基于冠层高度阈值识别的温室黄瓜整体自动落蔓装置。为保证黄瓜冠层特征提取的正确率,对8:00、12:00和18:00实时采集的黄瓜冠层图像进行预处理,基于Otsu算法获得平滑黄瓜冠层二值图像。采用霍夫变换算法识别黄瓜冠层顶端绳束,并利用统计学方法归纳出感兴趣区域中HSV色彩空间绿色部分各分量取值范围,研究感兴趣区域中绿色像素点占总像素点的比值变化规律。为防止黄瓜卷须缠绕秧蔓冠层顶端水平绳束,以黄瓜植株高度184~185 cm为落蔓控制目标,确定感兴趣区域绿色像素占比的平均值0.162~0.182为整体落蔓装置的落蔓阈值范围。结果表明,植株高度184~185 cm和高于185 cm落蔓次数占总试验次数比例分别为90%和10%。高于185 cm落蔓组中,最高植株距离顶端绳束(195 cm)的距离为9.2 cm,无黄瓜卷须缠绕黄瓜秧蔓冠层顶端水平绳束现象,采用感兴趣区域绿色像素点占比确定黄瓜落蔓阈值方法,能够满足黄瓜生产实际要求。

基于日光诱导叶绿素荧光的水稻叶氮含量估算

氮素是叶绿素的重要组成部分,是植物光合过程中各种酶的组成元素。传统叶氮含量测定具有破坏性,日光诱导叶绿素荧光SIF提供了从空间直接探测植被叶氮含量的可能。选取水稻作为实验对象,基于冠层日光诱导叶绿素荧光SIF数据、植被生理参数和冠层结构特征,构建叶氮含量反演模型,并探讨了不同生长阶段,各指标要素对模型的贡献度。结果表明:(1)花期后的日光诱导叶绿素荧光及其指数、植被生理和冠层结构数值均小于花期前,各指标会受到时期变化和施氮量控制的影响;(2)日光诱导叶绿素荧光SIF、叶绿素含量C_(ab)和荧光逃逸系数f_(esc)与基于质量的叶氮含量N_(mass)的拟合程度最优(R^(2)=0.675),使用SIF、C_(ab)和f_(esc)可以较好的指示N_(mass);(3)花期前SIF对估测N_(mass)的重要性最大,花期后C_(ab)和f_(esc)对估测N_(mass)的重要性最大。因此,物候会对叶氮含量估测产生影响,使用遥感手段反演叶氮含量需要一个多角度模型。研究结果可为基于卫星SIF反演区域农田叶氮含量和生态系统生产力提供依据。

外源褪黑素增强黄瓜耐盐性研究

盐胁迫是导致植物生长发育受阻和产量品质降低的主要环境因素之一,褪黑素是一种具有多效性的信号分子,在植物生长发育和应对环境压力方面具有重要的调控作用。本试验研究了不同浓度褪黑素(50,150和500μmol/L)对盐胁迫(150 mmol/L NaCl)下黄瓜叶片光合作用和氧化还原稳态的影响。结果表明,NaCl胁迫抑制了黄瓜的光合作用,增加了活性氧(ROS)的积累和膜损伤,褪黑素处理以剂量依赖的方式减轻了NaCl胁迫对黄瓜光合作用和氧化还原状态的影响。褪黑素能够改善植株的光合能力,这与其抑制气孔关闭、改善光能吸收和电子传递的作用紧密相关。此外,褪黑素还可降低氧化应激反应,这归因于氧化还原稳态的改善以及抗氧化酶活性的增强。

Some Aspects of Yield Physiology Research in Soybean

The paper reviews the factors and mechanisms involved in the regulation of seed growth,discusses the roles of source sink relationship in yield formation and effects of climate change and canopy photosynthesis on groth and yield in soybean.

Studies on forest ecosystem physiology: marginal water-use efficiency of a tropical, seasonal, evergreen forest in Thailand

Marginal water-use efficiency plays a critical role in plant carbon–water coupling relationships.We investigated the ecosystem marginal water-use efficiency(k)of a tropical seasonal evergreen forest to(1)determine the general pattern of k across time,(2)compare different models for calculating k,and(3)address how k varies with soil water content during different seasons.There was a U-shaped diurnal pattern in k,which was higher in the early morning and late afternoon.At other times of the day,k was lower and remained constant.Ecosystem k was higher in the wet season than in the dry season.All three models successfully captured the diurnal and seasonal patterns of k but differed in the calculated absolute values.The idea that k is constant on a subdaily scale was partly supported by our study,while a constant k was only true when data from the early morning and late afternoon were not included.Theλincreases with soil water content on a seasonal scale,possibly because early morningλremained low in dry conditions when the soil water content was low.

Effects of Irrigation Schedules on Photosynthetic Carbon Assimilation of Winter Wheat (Triticum aestivum L.) in North China Plain:from Leaf to Population

A field experiment was conducted to elucidate the regulation mechanism of different irrigation schedules on population photosynthetic of winter wheat. The experiment included five irrigation schedules, such as no irrigation （W0）, irrigation once at jointing （W1j） or at booting （W1b）, irrigation twice at jointing and booting （W2）, and irrigation three times at jointing, booting and grain-filling （W3） and three planting densities, such as 180 （D1）, 300 （D2） and 450 （D3） seedlings per square meter. The results indicated that irrigation significantly improved population photosynthesis. The relationship between population photosynthesis and irrigation time/volume was to some extent parabolic. Improvements in population photosynthesis （resulting from more irrigation time/volume） were mainly related to increase in leaf area index and population light interception. Population photosynthesis exhibited a significantly negative correlation with canopy light transmittance. Population photosynthesis at grain filling stage was significantly positively correlated with dry matter accumulation at post-anthesis and grain yield. Main effects and partial correlation analysis showed that population photosynthesis of W0, W1j, W1b and W3 were regulated by canopy light transmittance and leaf area. On the other hand, population photosynthesis of W2 was mainly influenced by flag leaf photosynthetic rate. On this basis, planting 300 seedlings per square meter was the optimum combination. The combination of W2D2 increased population photosynthesis during mid-late growth stages and extended high population photosynthesis duration, which ultimately increased grain yield.

Verification of Net Primary Production Estimation Method in the Mongolian Plateau Using Landsat ETM+ Data

We plan to estimate global net primary production (NPP) of vegetation using the Advanced Earth Observing Satellite\|Ⅱ (ADEOS\|Ⅱ) Global Imager (GLI) multi\|spectral data. We derive an NPP estimation algorithm from ground measurement data on temperate plants in Japan. By the algorithm, we estimate NPP using a vegetation index based on pattern decomposition (VIPD) for the Mongolian Plateau. The VIPD is derived from Landsat ETM+ multi\|spectral data, and the resulting NPP estimation is compared with ground data measured in a semi\|arid area of Mongolia. The NPP estimation derived from satellite remote sensing data agrees with the ground measurement data within the error range of 15% when all above\|ground vegetation NPP is calculated for different vegetation classifications.

Seed Scarification Improves Physiological Growth and Development of Bambara Groundnut (Vigna subterranea) Depending on Seed Coat Colour

This study was conducted to investigate the effect of scarification on bambara groundnut(Vigna subterranea)physiological growth and development and crop phenology.Bambara groundnut landrace seeds used in this study were characterized by seed coat colour(cream,light brown and brown).Seed scarification treatments were mechanical(sand paper)and chemical(sulphuric acid)scarification,while seeds that were not scarified served as a control.A completely randomized design with three replications was used.The parameters that were assessed were time to emergence,final emergence percentage,leaf number,chlorophyll content index(CCI),canopy diameter,plant height,chlorophyll fluorescence(Fv/Fm),photosynthetic performance index(Pi),time to flowering and time to senescence.CCI,leaf number and plant height were significantly(p<0.05)influenced by seed coat colour,seed scarification treatments and their interaction thereof.Seed scarification treatment had a significant effect on CCI,leaf number and plant height.Generally,seed scarification improved plant overall performance than the control.Chemical scarification presented superior performance of bambara groundnut growth and development.Light brown seeds produced plants with superior overall performance,having superior emergence,CCI,leaf number,and early flowering and senescence.Light brown seeds were followed by cream seeds in terms of superiority of plant performance,having produced plants with superior canopy diameter,plant height and Pi.Therefore,bambara groundnut farmers and researchers can successfully use scarification to improve its physiological growth and attain earlier phenological stages,hence maturity.At the same time,light brown seeds should be selected for cultivation to give the best plant performance.