Subjects: Biology >> Botany >> Applied botany submitted time 2022-06-07 Cooperative journals: 《广西植物》
Abstract： To explore the effects of different concentrations of melatonin on physiological and photosynthetic fluorescence characteristics of wheat seedlings. The growth morphology, photosynthetic, fluorescence parameters and antioxidant enzyme activity of wheat seedings treated with different concentrations of melatonin were determined by using Liangxing 99 as experimental material. The results were as follows: (1) 0.1 μmol·L-1 melatonin significantly increased the photosynthetic capacity of wheat plants, Chlorophyll a (Chl a), Chlorophyll b (Chl b) and Chlorophyll (a+b) [Chl (a+b)] increased to the maximum value when melatonin concentration was 0.1 μmol·L-1. Chlorophyll fluorescence parameters include parameters of quantum yield of regulated energy dissipation Y (NPQ), the electron transport rate (ETR) and non photochemical quenching (NPQ) also reaches the maximum at 0.1 μmol·L-1. The PSⅡ maximum photosynthetic efficiency (Fv/Fm) and maximum photochemical conversion potential (Fv/Fo) decreased with the increase of melatonin concentratio. Photochemical quenching (qL) decreased first and then increased with the increase of melatonin. (2) Compared with CK (0 μmol·L-1), low melatonin concentration significantly decreased peroxidase (POD) activity in wheat and decreased catalase (CAT) activity in wheat leaves, high melatonin concentration significantly increased POD activity in wheat. Low concentration of melatonin treatment significantly reduced the catalase (CAT) activity in wheat leaves by compared with CK. The content of malondialdehyde (MDA) in wheat roots decreased firstly and then increased with the increase of melatonin concentration. In conclusion, it suggested that appropriate melatonin treatment can promote the growth of wheat and maintain the photosynthetic capacity of wheat at a high level. Enzymes including POD and CAT can also regulate oxidative stress induced by different concentrations of melatonin in wheat seedlings. This study laid a foundation for further understanding the regulatory mechanism of melatonin in wheat.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Other Disciplines of Agriculture, Forestry,Livestock & Aquatic Products Science submitted time 2023-02-17 Cooperative journals: 《智慧农业（中英文）》
Abstract： Accurate acquisition of crop canopy biochemical information is of great significance for monitoring crop growth and guiding precise fertilization. Previous vertical distribution researches of crop biochemical information were mainly based on hyperspectral inversion, which was lack of the association of plant photosynthesis physiology. This study mainly investigated the vertical distribution characteristics of biochemical parameters such as chlorophyll, carotenoid, dry matter, and water content in the oilseed rape canopy under different nitrogen treatments at the mid-seedling stage. The photosynthetic performance of leaves was measured by using fast chlorophyll fluorescence technology, and linear regression and principal component analysis were further implemented to explore the internal relationship between fluorescence response and biochemical parameters. The results showed that: (1) The chlorophyll content, carotenoid content, dry matter and water content of the rape canopy at the mid-seedling stage all showed a parabolic vertical distribution, while the ratio of chlorophyll to carotenoids content gradually decreases with the leaf position and nitrogen treatments, which was the same as the vertical distribution pattern of fluorescence parameters such as driving force comprehensive performance (DFTotal) and end electron chain quantum yield (φRo) and other fluorescence parameters could be used to diagnose nitrogen stress; (2) JIP-test parameters, especially DFTotal, had a good performance to evaluate the chlorophyll/carotenoids, chlorophyll and dry matter content of oilseed rape leaves; (3) Nitrogen deficiency would weaken the PSII and PSI performance of oilseed rape leaves at the mid-seedling stage, and the maximum photochemical efficiency (φPo) could be used to diagnose nitrogen stress. There was a significant difference in the PSI performance, namely electron transfer efficiency at the end acceptors of leaves in the different leaf position, hence the comprehensive performance parameter DFTotal could be an effective characterization of the vertical heterogeneity of canopy biochemical parameters. These findings indicated the feasibility of applying the rapid chlorophyll fluorescence technology to crop biochemical information heterogeneity monitoring and provided new ideas and technical support for guiding precise fertilization and achieving high-quality and high-yield.
Subjects: Biology >> Botany >> Applied botany submitted time 2020-08-03 Cooperative journals: 《广西植物》
Abstract：为探讨半夏(Pinellia ternate)光系统对光照强度和温度日变化的适应机理，该文连续3天模拟了同一光照强度（0~1 600 μmol·m-2·s-1）日变化下低温（10~18 ℃）、中温（20~28 ℃）和高温（28~38 ℃）的环境条件，同时测定了光系统II（PSII）和光系统I（PSI）的叶绿素荧光参数，通过PSII 和PSI 光合活性和电子传递能力的变化研究半夏光合系统对光照强度和温度日变化的适应。结果表明:(1)PSII 最小荧光（Fo'）和PSII 反应中心激发能捕获效率（Fv'/Fm'）随光照的强度的增加而降低，光照强度的增加是导致光系统的活性降低的主要原因，低温会进一步导致光系统活性的降低；(2)光照强度和温度的增加使PSI 受体端热耗散效率[Y(ND)]上升、PSI 供体端热耗散效率[Y(NA)]则降低，光照强度的增加不会导致供体侧较大的激发压，但会使受体侧开始积累较大的激发压，而较低的温度会导致受体侧活性降低使供体侧积累较高的激发压；(3)高光（光强>900 μmol·m-2·s-1）对半夏的光抑制和光损伤导致了PSII 实际光化学量子产量[Y(II)]和PSI 实际光化学量子产量[Y(I)]的降低，低温进一步加剧了Y(II)和Y(I)的降低；(4)高光下PSI 的电子传递速率ETR（I）的增加启动了环式电子传递（CEF），较高的CEF 稳定了高温下PSII 的电子传递速率ETR（II）的同时保护PSII 免受光的损伤；(5)在3 d 的处理中虽然非光化学淬灭系数（NPQ）随光照强度的增加而上升，但相对于高温，低温下半夏较低的NPQ 使PSII 处非调节性能量耗散的量子产量[Y(NO)]一直处于最高水平表现出明显的光抑制。这些结果说明，低温降低了半夏对高光环境的适应能力，而高温通过增强NPQ、加速CEF 的产生，减少光抑制的产生，从而加速光反应的电子传递和维持光反应系统的稳定性。因此，低温胁迫会加剧半夏光系统的损伤，温度的适当提高可以增强半夏光反应系统对高光的适应性。
Subjects: Geosciences >> Geography submitted time 2023-08-01 Cooperative journals: 《干旱区地理》
Abstract：精准动态监测干旱胁迫下的玉米冠层叶绿素相对含量对提高我国玉米旱灾预警水平、实现田间精准灌溉具有重要的指示作用。以无人机多光谱影像为数据源，选用多种具有明确物理意义且与玉米冠层叶绿素相对含量SPAD（Soil and plant analyzer development）值相关性强的植被指数，利用多元逐步回归、支持向量机、BP神经网络（Back propagation neural network，BPNN）建立玉米冠层SPAD值的遥感监测模型并验证，选取最优估测模型提取各生育期不同程度干旱胁迫下的玉米冠层SPAD值，分析不同生育期玉米冠层SPAD值变化，探究不同干旱胁迫程度对玉米冠层SPAD值的影响。结果表明：不同生育期的玉米冠层叶绿素敏感的植被指数不同，且各生育期估测能力最优的反演模型不同。对比3种建模方法，BPNN模型的建模结果及验证结果最优，说明其估测能力及稳定性表现最好，可以作为基于无人机多光谱的玉米冠层SPAD值建模的优选方法。此外，干旱胁迫会降低玉米冠层SPAD值遥感监测模型的估测精度，对苗期的影响最为显著。轻度干旱对玉米冠层SPAD值影响不显著，可见玉米对干旱胁迫具有一定的适应性和抗逆性。因此，基于植被指数的BPNN模型可以更好地估算SPAD值，为基于无人机遥感的SPAD值监测提供一种新途径，为干旱胁迫下夏玉米冠层SPAD值的无损监测以及田间水分精准管理提供参考。
Subjects: Biology >> Botany >> Applied botany submitted time 2018-09-07 Cooperative journals: 《广西植物》
Abstract： Sugarcane is the most important sugar and energy crop. It is also the potential plant for remediation of high metal-polluted soil. To evaluate the physiological response of sugarcane to copper (Cu) stress, the weight of sugarcane,contentofchlorophyll,relativeelectricalconductivityinleavesandactivitiesofantioxidantenzymesin copper content in shoot and relative electrical conductivity in leaves increased in response to copper stress. The malonaldehyde (MDA) content was increased significantly by 25.5% under 400 祄ol稬-1 treatment at 24 h when compared with the control, and then the rate increase raised with the prolonging of treatment time. The MDA content increased notably after 72 h under 100祄ol稬-1 Cu treatment. The activity of SOD, POD and CAT changed significantly after 24 h treatment, but notable differences were found among different enzymes. The activity of SOD firstly dropped under 100 祄ol稬-1 treatment, and then increased with the increase of Cu content in solution under 200 祄ol稬-1 treatment, following with decrease of enzyme activity under 400 祄ol稬-1 treatment at 24 h, 48 h and 7 d. However, the activities of SOD increased with the increase of Cu content in solution at 72 h.The activity of POD increased with the increase of Cu content in solution, following with decline of enzyme activity under high content of Cu treatment at 24 h, 48 h and 7 h except at 72 d. The activity of CAT decreased significantly with the increase of Cu content in solution and with the prolonging of stress time. The activities of CAT declined by 89.98%, 96.88% and 98.50% under three Cu treatments, respectively at 7 d. Thus, the growth of sugarcane was greatly inhibited by copper stress and the change of SOD, POD and CAT activity mightplayimportantroleinalleviatingoxidativestresscausedbyCustress.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-10 Cooperative journals: 《中国生态农业学报》
Abstract：为探寻遮阴对马铃薯光合和荧光特性及吸收光能分配的影响, 本研究采用大田试验, 以马铃薯不耐弱光品种‘丽薯6 号’和耐弱光品种‘中薯20’为材料, 出苗后用遮光率70%的黑色遮阳网进行遮阴处理(T), 以自 然光照为对照(CK), 测定了遮阴30 d 后马铃薯叶片的光合作用、光响应曲线、CO2 响应曲线、光诱导曲线和叶绿素荧光参数的变化。结果表明: 1)遮阴后净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、最大净光合速率(Pmax)、光饱和点(LSP)、光补偿点(LCP)较CK 显著下降; ‘中薯20’的Pn、Pmax、LSP 较高, LCP 和暗呼吸速率(Rd)较低。2)不同基因型CO2响应参数无显著差异, 但‘中薯20’的最大羧化速率(Vcmax)和最大电子传递速率(Jmax)较高,CO2 补偿点(CCP)较低。3)高光诱导过程中, ‘中薯20’反应较快, 光合能力较强。4)初始荧光(Fo)、最大荧光(Fm)、最大光化学量子效率(Fv/Fm)较CK 显著增加, PSⅡ实际光化学量子效率(ΔF/Fm′)、表观电子传递速率(ETR)和光化学猝灭系数(qP)较CK 显著下降, 非光化学猝灭系数(NPQ)呈增加趋势。5)非光化学热耗散(ФNPQ)和荧光耗散途径(Фf,d)比例显著增加, 光化学猝灭耗散途径(ФPSⅡ)比例显著减少, 主要以增加热耗散为主。遮阴后, 耐弱光基因型‘中薯20’的NPQ 和ФNPQ 均高于不耐弱光的‘丽薯6 号’, 说明‘中薯20’的光合机构保护能力更强。综合分析表明, 遮阴后耐弱光基因型马铃薯具有较高的净光合速率、较低的光补偿点、较低的CO2 补偿点、较快的光诱导反应速度和较高的非光化学热耗散能力。
Subjects: Biology >> Ecology submitted time 2017-04-11 Cooperative journals: 《生态学报》
Abstract：为了探讨不同生境盐地碱蓬对低氮生境的适应机制，测定了盐渍环境下(200 mmol/L NaCl)不同浓度硝态氮(0.3、 5 mmol / L NO-3 ⁃N) 预处理两种生境盐地碱蓬经氮饥饿后的 NO-3 含量、硝酸还原酶( NR) 活性、光合特性及生长状况。 结果表明， 0.3 和 5 mmol / L NO-3 ⁃N 处理以及进行氮饥饿时，潮间带生境盐地碱蓬叶片 NO-3 含量均高于内陆生境盐地碱蓬。 与内陆生境盐 地碱蓬相比，氮饥饿后，潮间带生境盐地碱蓬叶绿素含量、NR 活性和光合放氧速率下降幅度均小于内陆生境盐地碱蓬，在 0.3 mmol / L NO-3 ⁃N 预处理进行氮饥饿时趋势更加明显。 0.3 mmol / L NO-3 ⁃N 预处理后氮饥饿对潮间带生境盐地碱蓬根冠比没有影响， 却降低内陆生境盐地碱蓬根冠比。 上述结果表明，低氮条件下潮间带生境盐地碱蓬具有较高的 NO-3 储存能力，在环境持续氮素缺 乏时具有较高的 NO-3 ⁃N 再利用能力，能更好地维持氮代谢以及光合性能。 说明潮间带生境盐地碱蓬能更好地适应低氮生境。
Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： In order to reveal the effects of soil microbial film sand fixation on photosynthetic and fluorescence characteristics of psammophyte seedlings, Ammopiptanthus mongolicus and Astragalus laxmannii seedlings were selected. Pot experiment with different application methods (spray, mix) and application amount (0, 1, 3, 5, 7 and 10 g kg -1). The characteristics of plant gas exchange and chlorophyll fluorescence after soil microbial biofilm formation were analyzed. The results show that: (1) When the application amount of bacterial was greater than 3 g·kg-1, the hardness, thickness of the consolidated layer and soil urease and sucrase activities were significantly higher than those of the control group (P<0.05). (2) The net photosynthetic rate of Astragalus laxmannii in 3-7 g·kg-1 treatment was significantly higher than that of the control (P<0.05). And the transpiration rate, net photosynthetic rate and intercellular CO2 concentration were significantly higher than those of Ammopiptanthus mongolicus (P<0.05). (3) The Fv/Fm of Astragalus laxmannii treated with more than 5 g kg-1 was significantly higher than that of the control group (P < 0.05). Except for 3 g kg-1 treatment, the Fv/Fm and QP of Ammopiptanthus mongolicus were higher than those of Astragalus laxmannii. (4) Soil properties, photosynthetic gas exchange and chlorophyll fluorescence were partially mediated models. The change of soil characteristics can directly affect the chlorophyll fluorescence characteristics of Ammopiptanthus mongolicus and Astragalus laxmannii. The soil microbial film increased the hardness, thickness of the consolidated layer by 3.84% and 152.85% on average, and the activities of catalase, urease and sucrase were increased by 93.37%, 170.68% and 256.03% on average. By improving soil quality and stomatal conductance of leaves, the photosynthetic efficiency and capacity of the two plants were enhanced. The net photosynthetic rate and Fv/Fm were increased by 28.48% and 0.84% respectively.
Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： Chlorophyll content is a crucial indicator for characterizing vegetation growth. In this study, we utilized high-spectral technology to rapidly monitor the chlorophyll contents of cotton leaves. We collected 125 cotton leaf seedling samples from Xinjiang and measured their chlorophyll content and spectral data. To achieve this, we employed various spectral preprocessing techniques and used a combination of vegetation indices. Subsequently, we constructed a whale optimization algorithm/random forest regression (WOA-RFR) quantitative inversion model for cotton leaf chlorophyll content. Finally, we conducted a comparative analysis, contrasting the results of the WOA-RFR model with those obtained from the support vector regression (SVR) and RFR models. The results indicated that the spectral transformation methods (logarithm transformation, fractional order differentiation, and wavelet transformation) effectively improved the correlation between the vegetation indices and the chlorophyll content. We also found that the best inversion performance was achieved with the WOA-RFR model using a fractional order differentiation with a transformation order of 0.9 and the Vogelmann3, RVI, DVI, SR 675-700 , Mndvi705, ND, VOG1, NVI, TVI, VOG2 combined vegetation indices. The model exhibited R2 values of 0.920 and 0.955 for the training set and validation set, respectively. The corresponding RMSE values were 0.987 and 0.986, while the MRE values were 0.013 and 0.014. Compared to the RFR and SVR models, the WOA-RFR model demonstrated higher predictive accuracy, and the optimization effect of the WOA algorithm was evident. As a result, this study provides valuable decision- making support for accurately quantifying cotton leaf chlorophyll content.
Subjects: Biology >> Botany >> Applied botany submitted time 2019-06-17 Cooperative journals: 《广西植物》
Abstract：人为践踏对湿地苔藓地被的影响一直不清楚。以采自长白山区月亮湾湿地开阔地的红型和林缘的黄绿型中位泥炭藓（Sphagnum magellanicum）为实验材料，室内模拟人为践踏，使用便携式调制叶绿素荧光仪，测定其叶绿素荧光参数，研究不同践踏强度、不同践踏轮次下，两类中位泥炭藓的荧光参数响应情况。结果显示：践踏第二轮，红型中位泥炭藓的PSII实际光量子产量[Y（II）]和相对电子传递速率（ETR）随践踏强度增大而减小，而黄绿型的践踏组均大于对照组；践踏结束时，红型的Y（II）和ETR的践踏组均显著低于对照组，而黄绿型只有轻度践踏低于对照组；黄绿型泥炭藓践踏组的非调节性能量耗散量子产量[Y（NO）]甚至要低于对照组。研究表明，尽管泥炭藓属植物能耐受一定的践踏胁迫，但随着践踏轮次增多、强度增大，胁迫累积效应将强烈抑制其生长；多见于开阔地的红型泥炭藓对人为践踏的耐受能力低于林缘生境的黄绿型泥炭藓。湿地保护与管理中，应减少游人践踏干扰，尤其要严格控制开阔地生境的游人进入。
Subjects: Biology >> Botany >> Botany research, experiment, plant evolution & development submitted time 2018-06-25 Cooperative journals: 《广西植物》
Abstract： The study investigated the allelopathic effects of aqueous extracts of Ageratina adenophora leaves on plant chlorophyll of 7 native species in China including Pinus massoniana , Cunninghamia lanceolata, Broussonetia papyifera, Castanea mollissima, Camellia oleifera, Zanthoxylum bungeanu and Pyracantha fortuneana. through five levels (30, 15, 5, 2.5, and 0 mg穖L-1) of treatment, After termination of the experiment, the contents of chlorophyll a and chlorophyll b in each of the 7 recipient plants were measured by the milling-ultraviolet spectrophotometer method, the parameters of seedling height, ground diameter, crown width and biomass were measured. Results showed: The effect of aqueous extracts from leaves of Ageratina adenophora on the chlorophyll content of 7 species of native plant seedlings showed no effect at low concentrations. High-concentration treatment had different effects on 7 Plant seedlings, Pinus massoniana showed an increase, while Camellia oleifera and Zanthoxylum bungeanu were not affected, while contents of chlorophyll a, chlorophyll b, and total chlorophyll of Cunninghamia lanceolata, Castanea mollissima, and Broussonetia papyiferaa were significantly decreased. Pyracantha fortuneana had only chlorophyll b decline.
Subjects: Biology >> Botany submitted time 2018-06-19 Cooperative journals: 《广西植物》
Abstract： ：以鄱阳湖湿地典型沉水植物苦草和马来眼子菜为供试材料, 通过吊桶实验控制水位，利用水下饱和脉冲调制叶绿素荧光仪（Diving-pam）研究不同水深（0.5、1.0、1.5、2.0、2.5 m）对两种植物叶片最小荧光Fo、最大荧光Fm、 PSⅡ最大光化光效率Fv/Fm、有效量子产量Y(Ⅱ)、光化学淬灭系数qP、非光化学淬灭系数qN、非调节性能量耗散的量子产量Y(NO)等荧光参数的影响,探讨各个参数随水深的变化规律。研究结果表明：水深1.5-2.0 m处苦草生物量最大，1.0-1.5 m处马来眼子菜生物量最大；两种植物的Fo均先降低后升高，而荧光参数（Fm、Fv/Fm、Fv/Fo、Y(Ⅱ)、qP）均呈现先升高后降低趋势；2.0 m处苦草的Fv/Fm、Fv/Fo达到最大，1.5 m处马来眼子菜达到最大；相同水深下，马来眼子菜的qN比苦草低，与qP变化趋势相反；苦草的Y(Ⅱ)最大值出现在水深1.5-2.0 m范围内，马来眼子菜的Y(Ⅱ)最大值出现在1.5 m处；两者Y(NO)随水深变化均表现出显著差异，过高或过低水深均抑制植物生长；相对光合电子传递速率ETR在不同的水深处理间均差异显著，苦草的最大ETR比马来眼子菜小，说明其有较强的耐弱光能力。综上所述，可通过测定植物叶片荧光特性来反映水深变化，为湖泊水位调控提供参考。在试验条件下,水深1.5-2.0 m苦草光合能力最强，最适宜生长；水深1.0-1.5 m最适宜马来眼子生长。
Subjects: Geosciences >> Geography submitted time 2020-12-17 Cooperative journals: 《干旱区研究》
Abstract：以关中地区冬小麦为研究对象，无人机为平台搭载的UHD185成像光谱仪获得冬小麦农田高光谱影像，并从中提取波段信息，以传统光谱指数和新光谱指数为自变量构建预测模型，比较模型精度并制作冬小麦叶片叶绿素含量分布图。结果表明：各预测模型中以新光谱指数构建的预测模型精度明显高于传统光谱指数模型，其中，SPAD-NDSI模型精度最高（R2=0.6308，RMSE=1.9766）；通过反演叶片叶绿素分布图并对填图结果进行检验可知，SPAD-NDSI模型填图效果最佳（R2=0.7013，RMSE=1.4548），可以作为冬小麦叶片叶绿素含量无人机高光谱影像遥感反演估算的基本模型。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-11 Cooperative journals: 《干旱区研究》
Abstract：以渭干河—库车河绿洲(渭—库绿洲)为研究区，采用在机器学习方面具有明显优势的随机森林回归算法，对绿洲内的4种典型植被(棉花、芦苇、杨树、大枣)叶片的叶绿素相对含量(soil and plant analyzer development, SPAD)进行估算和验证。首先基于“红边”处光谱信息丰富的哨兵2号(Sentinel-2)影像和由其衍生的一阶微分、二阶微分影像各提取23种对叶绿素敏感的宽波段光谱指数，加入3种影响植物生长的土壤参量(土壤含水量，土壤有机质，土壤电导率)作为影响叶片SPAD的特征变量，再根据以上特征变量对每种植被叶片各建立3种方案的SPAD估算模型，从而实现对绿洲内植被叶绿素的监测。结果表明：① 影像经一阶微分再提取的植被指数相比原位光谱植被指数，在SPAD估测模型中起到了更重要的作用，在随机森林算法的重要性排序中位居前列；② 4种植被叶片的SPAD估测模型都取得了不错的效果，芦苇叶片尤为显著，确定系数(R2)达到了0.926；③ 分析对比3种方案下模型预测能力，方案3(包含土壤参量)的预测能力卓越〔2.143方案1>方案2，土壤属性和模型预测结果有较强的非线性相关。Sentinel-2数据具有理想的估算绿洲植被叶绿素含量的潜力，提供了一种高效、低成本、潜在高精度的方案来估算叶绿素含量，可为干旱区绿洲农业、生态系统实现更有效的保护和管理提供参考。
Subjects: Biology >> Botany >> Applied botany submitted time 2019-08-26 Cooperative journals: 《广西植物》
Abstract： In order to explore the tolerance and reaction mechanism of Handroanthus chrysotrichus towards coldness, 1 a seedlings of H. chrysotrichus were put under artificially controlling low temperature treatments. Physiological indexes and chlorophyll fluorescence parameters were measured. The result shows that under low temperature stress of 6 ℃ or above, seeldings can improve their cold tolerance and protect themselves by enhancing SOD activity, SS contents and Pro contents. In addition, seedlings can also prevent their photosynthetic system from cold damaging through improving NPQ. When the temperature reaches to 2 ℃, both PSⅡreaction center and photosynthetic system will be badly damaged. From these changes, we deduce that seedlings of H. chrysotrichus can resist to low temperature ranging 2-5 ℃ and prevent the meselves from coldness through self-adjustment. However, the critical point still needs to be determined. Our paper also finds out that when facing low temperature 6 ℃ or above, SS contents rapidly rise up. When the temperature reaches to 2 ℃ or below, Pro contents remarkably rise up. Perhaps seedlings of H. chrysotrichus can protect themselves from low temperature 6 ℃ or above by enhancing SOD activities and SS contents. Seedlings of H. chrysotrichus will mitigate damages of low temperature 2 ℃ or below by enhancing SOD activities and Pro contents. It is concluded that the seedlings of H. chrysotrichus could not resist the freezing damage caused by low temperature below 0 ℃, but have certain tolerance to low temperature above 0 ℃. The results are beneficial to both selecting resistent varieties and promoting cultivation. It is also good for exploring cold tolerant ability of plants.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-10-20 Cooperative journals: 《中国生态农业学报》
Abstract：为了探明弱光条件下小麦光合速率降低的原因, 为黄淮海麦区小麦生产中合理施氮和高产高效栽培提供理论依据, 通过田间试验研究了拔节期至成熟期弱光胁迫(透光率为50%的黑色遮阳网遮阴)和氮素水平 [N0, 0 kg(N)hm2; N1, 120 kg(N)hm2; N2, 240 kg(N)hm2]对冬小麦旗叶光合特性及产量的影响。结果表明:冬小麦拔节期至成熟期长期遮阴, 导致旗叶叶绿素含量、PSⅡ荧光光化学猝灭系数(qP)和实际光化学量子产量(ΦPSII)在3 个施氮水平下均显著增加, 其中以N2 施氮水平下增幅最大, 同时显著降低了叶绿素a/b 和荧光非光化学猝灭系数(qN), 进而提高了旗叶光化学效率, 降低了热能耗散, 提高光能利用率。在开花期至灌浆中期,由于光能不足造成小麦旗叶净光合速率Pn 降低, 而在灌浆后期, 遮阴处理较正常光照能维持较高的叶绿素含量和光能转化效率, 从而Pn 高于正常光照。在相同光照条件下, 随施氮量增加, 小麦旗叶净光合速率Pn、叶绿素含量、PSⅡ荧光光化学猝灭系数(qP)和实际光化学量子产量(ΦPSⅡ)显著提高, 这有利于植株充分利用光能,增强光合作用。弱光导致穗数、穗粒数及千粒重显著降低(P<0.05), 穗粒数降低幅度最大(13%~46.8%), 千粒重降低幅度最小(3.4%~8.5%), 穗数的降低幅度为8.6%~22.5%, 严重影响氮肥的增产效应。遮阴和施氮水平间交互显著影响了叶绿素含量、穗粒数和产量, 但对其他指标影响并不显著。综合而言, 增施氮肥缓解了弱光胁迫对光合作用的不利影响, 遮阴条件下施氮处理(N1、N2)净光合速率Pn 较对照(N0)增幅为11.5%~27.4%, 其中以N2[240 kg(N)hm2]水平增幅最大。在不同施氮水平下, 遮阴处理均提高了光能转化效率, 但遮阴显著降低了植株光合速率及产量构成因素, 导致产量显著降低(P<0.05)。
Subjects: Biology >> Botany >> Applied botany submitted time 2024-04-17 Cooperative journals: 《广西植物》
Abstract： Vatica guangxiensis is a national first-class protected wild plant and extremely small populations wild plant. This paper provides a comparative analysis of the photosynthetic physiological characteristics and structural features of Vatica guangxiensis seedlings and adult trees. The Li-6400 portable photosynthesis measurement system analyzer and vacuum electron scanning microscope were utilized to investigate the differences between the photosynthetic capacity and leaf structure of leaves at different stages of growth and development. The results were as follows: (1) The right-angled hyperbolic modified model was the best model to fit the light response of Vatica guangxiensis seedlings and adult plants. (2) The maximum net photosynthetic rate(Pnmax), light saturation point (LSP) and dark respiration rate (Rd) of adult leaves were significantly higher than those of seedlings, the light compensation point (LCP) of adult plants was lower than that of seedlings(P<0.05). (3) Chlorophyll a, chlorophyll b, chlorophyll (a+b) and carotenoids in seedlings were significantly lower than in adult plants(P<0.05). (4) The stomatal long axis, stomatal organ area and stomatal density of adult plants were significantly higher than those of seedlings; the leaf area and specific leaf weight (SLW) of adult plants were significantly larger than seedling (P<0.05), and the specific leaf area (SLA) was smaller than seedling. In summary, Vatica guangxiensis exhibits photosynthetic characteristics of a shade-loving seedling and a sun-loving adult tree. The seedlings have weak light adaptation ability and light energy utilization, and are unable to photosynthesize sufficiently to meet their growth needs due to excessive shading by adult trees. This is a significant reason why seedlings are unable to grow into large trees. Therefore, for insitu conservation of Vatica guangxiensis, human interference can be used to artificially create ‘windows’ in the tree layer to provide sufficient light sources. This is conducive to the growth of Vatica guangxiensis seedlings into large trees and the renewal of the population. On the other hand, for the introductory cultivation of Vatica guangxiensis, the seedlings need to be appropriately shaded and transplanted to a certain degree of shade. During the initial cultivation process, it is important to provide appropriate shading for seedlings and transplant them to an environment with a suitable level of shade.
Subjects: Statistics >> Social Statistics submitted time 2023-12-04 Cooperative journals: 《智慧农业（中英文）》
Abstract： Objective Chlorophyll fluorescence (ChlF) emission from photosystem II (PSII) is closely coupled with photochemical reactions. As an efficient and non-destructive means of obtaining plant photosynthesis efficiency and physiological state information, the collection of fluorescence signals is often used in many fields such as plant physiological research, smart agricultural information sensing, etc. Chlorophyll fluorescence imaging systems, which is the experimental device for collecting the fluorescence signal, have difficulties in application due to their high price and complex structure. In order to solve the issues, this paper investigates and constructs a low-cost chlorophyll fluorescence imaging system based on a micro complementary metal oxide semiconductor (CMOS) camera and a smartphone, and carries out experimental verifications and applications on it. Method The chlorophyll fluorescence imaging system is mainly composed of three parts: excitation light, CMOS camera and its control circuit, and a upper computer based on a smartphone. The light source of the excitation light group is based on the principle and characteristics of chlorophyll fluorescence, and uses a blue light source of 460 nm band to achieve the best fluorescence excitation effect. In terms of structure, the principle of integrating sphere was borrowed, the bowl-shaped light source structure was adopted, and the design of the LED surface light source was used to meet the requirements of chlorophyll fluorescence signal measurement for the uniformity of the excitation light field. For the adjustment of light source intensity, the control scheme of pulse width modulation was adopted, which could realize sequential control of different intensities of excitation light. Through the simulation analysis of the light field, the light intensity and distribution characteristics of the light field were stuidied, and the calibration of the excitation light group was completed according to the simulation results. The OV5640 micro CMOS camera was used to collect fluorescence images. Combined with the imaging principle of the CMOS camera, the fluorescence imaging intensity of the CMOS camera was calculated, and its ability to collect chlorophyll fluorescence was analyzed and discussed. The control circuit of the CMOS camera uses an STM32 microcontroller as the microcontroller unit, and completes the data communication between the synchronous light group control circuit and the smartphone through the RS232 to TTL serial communication module and the full-speed universal serial bus, respectively. The smartphone upper computer software is the operating software of the chlorophyll fluorescence imaging system user terminal and the overall control program for fluorescence image acquisition. The overall workflow could be summarized as the user sets the relevant excitation light parameters and camera shooting instructions in the upper computer as needed, sends the instructions to the control circuit through the universal serial bus and serial port, and completes the control of excitation light and CMOS camera image acquisition. After the chlorophyll fluorescence image collection was completed, the data would be sent back to the smart phone or server for analysis, processing, storage, and display. In order to verify the design of the proposed scheme, a prototype of the chlorophyll fluorescence imaging system based on this scheme was made for experimental verification. Firstly, the uniformity of the light field was measured on the excitation light to test the actual performance of the excitation light designed in this article. On this basis, a chlorophyll fluorescence imaging experiment under continuous light excitation and modulated pulse light protocols was completed. Through the analysis and processing of the experimental results and comparison with mainstream chlorophyll fluorometers, the fluorescence imaging capabilities and low-cost advantages of this chlorophyll fluorometer were further verified. Results and Discussions The maximum excitation light intensity of the chlorophyll fluorescence imaging system designed in this article was 6250 μmol/(m2·s). Through the simulation analysis of the light field and the calculation and analysis of the fluorescence imaging intensity of the CMOS camera, the feasibility of collecting chlorophyll fluorescence images by the OV5640 micro CMOS camera was demonstrated, which provided a basis for the specific design and implementation of the fluorometer. In terms of hardware circuits, it made full use of the software and hardware advantages of smartphones, and only consisted of the control circuits of the excitation light and CMOS camera and the corresponding communication modules to complete the fluorescence image collection work, simplifying the circuit structure and reducing hardware costs to the greatest extent. The final fluorescence instrument achieved a collection resolution of 5 million pixels, a spectral range of 400~1000 nm, and a stable acquisition frequency of up to 42 f/s. Experimental results showed that the measured data was consistent with theoretical analysis and simulation, which could meet the requirements of fluorescence detection. The instrument was capable of collecting images of chlorophyll fluorescence under continuous light excitation or the protocol of modulated pulsed light. The acquired chlorophyll fluorescence images could reflect the two-dimensional heterogeneity of leaves and could effectively distinguish the photosynthetic characteristics of different leaves. Typical chlorophyll fluorescence parameter images of Fv/Fm, Rfd, etc. were in line with expectations. Compared with the existing chlorophyll fluorescence imaging system, the chlorophyll fluorescence imaging system designed in this article has obvious cost advantages while realizing the rapid detection function of chlorophyll fluorescence. Conclusions The instrument is with a simple structure and low cost, and has good application value for the detection of plant physiology and environmental changes. The system is useful for developing other fluorescence instruments.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-05-21 Cooperative journals: 《广西植物》
Abstract： As a shade plant with high ornamental value, Saxifraga stolonifera is often used in landscape of courtyards and gardens. The light intensity may have an important impact on its growth performance, especially on leaf color, formation and coloration of leaf variegation, which subsequently affects its ornamental value. However, the related study has not been reported before. In order to explore the adaptability of different cultivars of S. stolonifera to light intensity and understand their light or shade tolerance, three internationally-registered cultivars raised in China were used as the experimental material, the effects of five light intensity treatments (100%, 85%, 60%, 40% and 15%) on plant growth and development and photosynthetic physiological indexes were investigated. The suitable indexes of light intensity for Saxifraga were screened by the principal component analysis, and the light tolerance of the cultivars was evaluated by membership function analysis. The results were as follows: (1) The number of stolons, number of blades, leaf length, leaf width, leaf area, specific leaf area, chlorophyll a, b and total chlorophyll contents increased with shading. (2) The fresh and dry weight above ground, stolon diameter, and the contents of carotenoid and flavonoids increased first and then decreased. (3) The initial fluorescence values and the contents of soluble sugar, soluble protein and malondialdehyde of the leaves decreased with shading. (4) By analysis of principal component and membership function, the significant differences were found in the adaptability of the three cultivars to light intensity, ‘Xue Wen’ > ‘Tianmu Enci’ > ‘Hei Kui’. In which, 40% light intensity is optimal for ‘Xue Wen’, and 15%-40% light intensity is optimal for ‘Tianmu Enci’ and ‘Hei Kui’. Therefore, in horticultural practice, the suitable light intensity should be considered according to the cultivars of Saxifraga.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Basic Disciplines of Agriculture submitted time 2017-11-07 Cooperative journals: 《中国生态农业学报》
Abstract：为阐明低温胁迫下激素含量对冬油菜枯叶期的调控和对抗寒性的响应, 为冬油菜抗寒性研究提供依据, 以8 份不同抗寒等级的白菜型和甘蓝型冬油菜为材料, 利用盆栽试验, 待幼苗长至5~6 片真叶时在人工气候箱中进行低温处理(25 ℃、10 ℃、2 ℃、5 ℃), 分析低温胁迫后冬油菜内源ABA、GA 含量和叶绿素的变化。回归分析表明温度与ABA 含量存在显著的负相关, 回归方程符合y=ax+b, 随着温度的降低, 内源ABA 含量呈先缓慢(10 ℃)后迅速上升(2 ℃、5 ℃)的趋势, 且温度处理间、温度与品种互作间差异极显著; 由于激素间的拮抗作用GA 含量变化则恰好相反。当在0 ℃以上低温时, 品种间ABA 含量无明显差异, 当温度降到5 ℃, 白菜型冬油菜ABA 含量明显高于甘蓝型, 抗寒性强的品种高于抗寒性弱的品种。ABA 含量的升高导致叶绿素含量的变化,随着温度降低, 叶绿素含量呈先降低后增加的趋势, 但总体呈下降趋势, 且白菜型冬油菜和甘蓝型冬油菜之间存在不同的响应机制, 这种作用使白菜型冬油菜叶绿素含量低于甘蓝型冬油菜, 导致白菜型冬油菜枯叶期提前,提早进入越冬期, 增加了对低温冻害的御性和避性。因此, 随着温度的降低冬油菜叶片ABA 含量上升, 叶绿素降解, 白菜型冬油菜更早进入枯叶期, 枯叶期较早和降温后ABA 含量高是白菜型冬油菜抗寒性较强的主要原因。
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