Influence of Harvest Periods on Cassava (Manihot esculenta Crantz) Agronomic Traits and Physiological Response to Post-Harvest Physiological Deterioration

Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest due to a rapid post-harvest physiological deterioration (PPD) makes the roots to be considered as a risky product to market. The objectives of this work were to investigate the influence of two harvest periods on cassava agronomic parameters and their physiological response to PPD. Three cassava cultivars 96/1414, I070593 and LMR were selected for the experiment and harvested at 10 and 12 months after planting (MAP). The response to PPD was assessed during storage at 0, 3, 8 and 15 days after harvest (DAH). Total proteins content, soluble sugars and starch, total polyphenols compounds, polyphenoloxidase and peroxidase activities were recorded during storage. Results showed large variation among the parameters at the two harvest periods across the cultivars. High number of tubers was recorded in all the cultivars at 12 MAP and a significant increase in storage roots length was observed in 96/1414 and LMR from 10 MAP to 12 MAP (25 ± 5.1 to 41.3 ± 5.9 and 22.6 ± 3.3 to 27.9 ± 4.8) respectively. A reduction of about 49% of tubers weight was observed in I070593 from 10 to 12 MAP while an increase of about 36% and 11% were recorded in LMR and 96/1414 respectively. Tubers from I070593 showed less susceptibility to PPD when harvested at 10 MAP compared to those from LMR and 96/1414 where less susceptibility to PPD were recorded at 12 MAP. An increase in soluble sugars content, total proteins content and peroxidase activity subsequently to a decrease in starch content were recorded during storage from 8 to 15 days after harvest especially at 10 MAP in I070593 and at 12 MAP in LMR and 96/1414. High content of total phenolic compounds and less activity of polyphenol oxidase were correlated to PPD susceptibility. This work opens a new insight issue of the consideration of the appropriate harvest time of the cultivars as a tool to better control the onset of postharvest physiological deterioration.

Study on chemical composition of Viscum coloratum and its HPLC fingerprint in different harvest periods

The purpose of this study was to evaluate the similarity of chemical profile of Viscum loloratum harvested in different months using high performance liquid chromatography(HPLC)fingerprint and multivariate statistical analysis,and to determine the optimal harvest time of Viscum coloratum.8 compounds were isolated from Viscum coloratum by a variety of isolation techniques,3 of which were isolated from the genus Viscum L.for the first time.The fingerprint of Viscum coloratum was established by HPLC,and 16 common peaks were obtained,4 of which were identified by comparison with the reference substances.Results showed that the Viscum coloratum harvested in 6 months could be roughly divided into three groups based on the chemical profiles,and the Viscum coloratum harvested in January had higher levels of the marked compounds.The HPLC fingerprint objectively reveals the characteristics of Viscum coloratum harvested in different months,which can be used to evaluate and control the quality of Viscum coloratum harvested in different months.

Effects of Different Harvest Periods on Seed Quality of Alpinia oxyphylla Miq.

[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla Miq. seeds during different harvest periods were analyzed and compared. [Results] The results showed that the A. oxyphylla Miq. fruit picking period was closely related to the seed quality,and the seed maturity was highest 100 d after the flowering of A. oxyphylla Miq.,that is,the A. oxyphylla Miq. fruit skin turned from green to yellow( yellow-green),the peel had a small number of brown spots,it was spicy enough,the fruit dry/fresh weight ratio was greater than0. 34,the seed thousand kernel weight reached 11 g or more,and the dried seed moisture content was 13. 01%. Using the TTC method,the seed viability index was determined to be 85%,and in this case,it was the best time of harvesting seed. The water permeability of A. oxyphylla Miq. seed was poor,and the seed imbibition and water absorption time was long,about 72 h. The maximum water absorption rate was about23. 71% at the imbibition and water absorption stage,and it was inferred that the A. oxyphylla Miq. seeds were hard seeds. The germination time of A. oxyphylla Miq. seeds was long,the mature A. oxyphylla Miq. seeds began to germinate on the 12 th d,and the germination rate reached 75. 56% on the 50 th d. [Conclusions] This study determined the optimum harvest period of A. oxyphylla Miq. seeds,clarified the biological characteristics of slow seed water absorption and long germination cycle,and concluded that the seed coat was the main factor leading to slow seed water absorption and long seed germination cycle.

Comprehensive evaluation of Korla fragrant pears and optimization of plucking time during the harvest period

To optimize the harvest of Korla fragrant pears and to provide a theoretical basis for post-harvest processing,a total of 26 basic indices of Korla fragrant pears,including their morphology,quality,and softening age,were investigated.The harvest period ranged from August 22nd to October 6th,samples were collected every 5 d(totally 10 plucking days,indicated as H1-H10).The results indicated that changes in pectin content were the main causes of softening in fragrant pears.The scavenging of free radicals mainly occurred because of the collaborative effects of superoxide dismutase(SOD)and catalase(CAT).In the harvest periods H1-H3,the hardness,titratable acid(TA),chlorophyll content,density,and diameter of the stone cells,as well as the cellulose and hemicellulose content of the Korla fragrant pears were at their highest.During the periods H7-H10,the single-fruit weight,fruit horizontal and vertical diameter,color coordinates L,a*,b*,soluble-solids content(SSC),SOD activity,CAT activity,and water-soluble pectin were higher than in the other plucking periods.The highest vitamin C(VC)content and moderate values for a variety of indicators were observed during H3-H7.Variations in the Korla fragrant pears during H1-H3 mainly manifested through changes in softening-related parameters.During H3-H10,changes in the softening-related,aging-related,color-related,and quality indices had a dominant role.On this basis,some suggestions for the post-harvest processing of fragrant pears have been proposed.Fruit,during H1-H3,are suitable for transportation and storage;during H7-H10 are suitable for fresh-eating and further processing;and during H3-H7,exhibited moderate values for a variety of indicators and had the highest commercial value.This research provides a systematic evaluation of the characteristics of mature Korla fragrant pears during the harvest period and can form the basis for fruit quality control and processing of Korla fragrant pears.

Existence of two periodic solutions of a ratio-dependent Holling-Taner model with infinite delay and prey harvest

This paper considers a class of ratio-dependent Holling-Taner model with infinite delay and prey harvest, which is of periodic coefficients. By means of the coincidence degree theory, a set of sufficient conditions for the existence of at least two positive periodic solutions of this model is established.

Modeling and analysis of piezoelectric beam with periodically variable cross-sections for vibration energy harvesting

A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigated by the generalized differential quadrature rule （GDQR） method. The GDQR method is also used to calculate the forced vibration response of the beam and voltage of each piezoelectric layer when the beam is subject to a sinusoidal base excitation. Results obtained from the analytical method are compared with those obtained from the finite element simulation with ANSYS, and good agreement is found. The voltage output of this periodic beam over its first band gap is calculated and compared with the voltage output of the uniform piezoelectric beam. It is concluded that this periodic beam has three advantages over the uniform piezoelectric beam, i.e., generating more voltage outputs over a wide frequency range, absorbing vibration, and being less weight.

全株小麦青贮适宜收获期及青贮添加剂配比技术的研究

为了确定全株小麦作为青贮饲料的适宜收获期及最佳的青贮添加剂配比组合,首先分析了全株小麦开花期、乳熟期、蜡熟期的干物质产量及营养成分含量,综合各生育期全株小麦的各项饲用指标(可消化干物质产量、非结构性碳水化合物含量等),表明蜡熟期是最适宜作为青贮的时期。其次通过添加不同浓度的乳酸菌与糖蜜来研究添加剂配比组合对全株小麦青贮料发酵效果及养分损耗,结果表明同时添加两种添加剂的全株小麦青贮料的饲用品质和发酵品质显著优于只添加其中一种添加剂。两种添加剂配比中,添加乳酸菌浓度较低时(≤0.02‰),糖蜜添加浓度为2%较添加浓度为1%的全株小麦青贮料的饲用品质和发酵品质好;添加乳酸菌浓度较高时(≥0.04‰),糖蜜添加浓度的变化对全株小麦青贮料的饲用品质和发酵品质影响不显著。研究结果可为全株小麦青贮适宜收获期以及乳酸菌与糖蜜配比组合在青贮饲料中应用提供参考。

贯叶金丝桃(Hypericum perforatum)种子灌浆与发芽特性研究

贯叶金丝桃(Hypericum perforatum)是抗抑郁中药的基原植物,以有性繁殖为主,种子微小。为了揭示贯叶金丝桃种子发育规律,明确种子适宜采收期,以甘肃礼县栽培的2年生贯叶金丝桃为研究对象,于开花后第5天开始,每隔3 d测定种子粒重变化动态,并拟合Logistic曲线方程,最后测定各时期采收种子的发芽指标。结果表明:贯叶金丝桃种子灌浆持续期44 d,籽粒干质量变化符合Logistic生长曲线:开花后第5~11天为渐增期,第11~32天为快增期,第32~44天进入稳增期后略有下降。在灌浆过程中,种子鲜质量呈先升高后下降的动态变化趋势,在花后第32天达到最大值0.2697 g;灌浆速率和脱水速率呈波动趋势,种子干质量与平均灌浆速率、灌浆持续期呈极显著正相关,与含水量呈极显著负相关。种子发芽率和发芽指数在开花后44天达到最大,发芽势在开花后41天达到最大,发芽率、发芽势和发芽指数均与灌浆持续期呈极显著正相关,与含水量呈极显著负相关。以上说明甘肃礼县贯叶金丝桃繁种时以开花后44天左右(8月9日前后)为种子采收适宜期,过早采收和延迟采收均影响种子发芽质量。

北五味子的采收加工与炮制研究进展

总结近年采收期对北五味子中木脂素、有机酸、多糖等多种成分的影响,考察晒干、阴干、烘干等产地初加工方法,以及醋制工艺、酒制工艺、盐制工艺等,炮制后北五味子中化学成分的变化,炮制后北五味子镇静催眠、降血糖、保肝和保肾等药理作用变化情况,指出北五味子具有多种药理活性,在多种常用复方中均有使用,应用前景广泛,但仍需要运用现代科学技术全面开展北五味子采收、加工、炮制等方面的研究,为北五味子的临床合理应用提供参考。

Periodic Solution for Stochastic Predator-Prey Systems with Nonlinear Harvesting and Impulses

In this paper, astochastic predator-prey systems with nonlinear harvesting and impulsive effect are investigated. Firstly, we show the existence and uniqueness of the global positive solution of the system. Secondly, by constructing appropriate Lyapunov function and using comparison theorem with an impulsive differential equation, we study that a positive periodic solution exists. Thirdly, we prove that system is globally attractive. Finally, numerical simulations are presented to show the feasibility of the obtained results.

不同产地沃柑品质差异分析

以4个产地(武鸣、全州、贵港、靖西)不同采收期的沃柑为研究对象,分析其色泽、理化特性及营养成分变化。结果表明:沃柑品质因产地和采收期不同而呈现出差异,随着采收期延长,4个产地的沃柑L*值、b*值、可滴定酸、总酚及柠檬苦素含量均呈降低趋势,a*值、可溶性固形物含量、固酸比、维生素C含量及类胡萝卜素含量不断升高,氨基酸含量呈现动态变化趋势。聚类分析显示武鸣、全州、贵港、靖西采收期Ⅰ的沃柑归为一类,全州、贵港采收期Ⅱ、Ⅲ和武鸣、靖西采收期Ⅱ的沃柑归为一类,武鸣、靖西采收期Ⅲ的沃柑归为一类。研究结果表明,采收期Ⅰ、Ⅱ的武鸣、全州、贵港、靖西沃柑品质无差异,采收期Ⅲ的武鸣、靖西沃柑品质优于全州、贵港沃柑,采收期Ⅲ的武鸣、靖西沃柑果实色泽诱人、酸甜可口无苦涩味、营养丰富,较适合鲜食和加工。

Existence of Two Periodic Solutions of a Delayed Single Species Model with Feedback Regulation and Harvest Term

借助于巧合度理论的继续定理，有反馈规定和收获术语的一个推迟的单个种类模型的二个周期的答案的存在被获得。

全株大豆和玉米混贮采收时期和混合比例研究

为了确定全株大豆进行青贮的最佳采收时期,制定全株大豆、玉米混合青贮的最佳比例,本研究把不同品种大豆在不同生育期进行采收,检测饲草价值,通过对比确定最佳采收时期。将玉米和濮豆5110按照鲜重比1∶0、3∶1、2∶1、1∶1、1∶2、1∶3、0∶1进行混合青贮,并对混合青贮的饲用品质进行测定,采用成分分析和模糊隶属函数对不同比例混合青贮品质进行评定,以筛选出最适宜混合比例。结果显示:比例为1∶1混合青贮的饲用品质、发酵品质和能量值最高,且相对饲用价值在此处理下达到最佳。同时,通过隶属函数得知1∶1混合综合得分为0.78,综合性能最好。结果说明在结荚期后期或者鼓粒期前期采收的全株大豆和1/2~1/3乳线区的全株玉米以1∶1的比例混合青贮效果最佳。

中国黄连木雄花序不同花期营养品质变化

为了确定黄连木(Pistacia chinensis Bunge)雄花序食用的最佳采收期,以提供最佳营养品质的雄花序,提高黄连木的综合利用率。测定雄花序7个不同生长时期的17个营养指标,探究雄花序生长过程中营养品质变化并进行主成分综合评价。结果表明:随着黄连木雄花序生长时期推移,雄花序外观整体大小呈先增大后平缓增大的趋势,含水率随雄花序的生长呈先升高后降低的趋势,在盛花前期达到最高,为70%左右。黄连木雄花序的可溶性糖质量分数随生长周期的增加呈先上升后降低的趋势,总体质量分数为64.44~111.14 mg·g^(-1),最大值出现在盛花期。蛋白质质量浓度在盛花期前较为稳定,在盛花期后呈下降趋势,总体质量浓度为151.25~265.625 g·L^(-1)。总氨基酸质量摩尔浓度表现出波动上升的趋势,总体质量摩尔浓度为7.41~18.31μmol·mg^(-1)。雄花序内的9种矿质元素质量分数变化不一。N元素呈波动下降的趋势,总体质量分数为24.20~42.50 g·kg^(-1);P元素总体变化较为稳定,在盛花期后出现下降,总体质量分数为2724.00~6468.00 mg·kg^(-1);K元素表现为波动变化且稍有上升的趋势,总体质量分数为22526.67~37811.33 mg·kg^(-1);Ca元素表现为先下降后上升,总体质量分数为1480.00~4401.33 mg·kg^(-1);Mg元素质量分数总体较稳定,为1359.33~1527.67 mg·kg^(-1),在盛花期前后达到最高;Fe元素质量分数在盛花前期之前较为稳定,在盛花前期之后急速上升,至末花期达到最大值,总体质量分数为132.67~391.33 mg·kg^(-1);Mn元素呈先上升后下降的趋势,在盛花期前后达到最高,总体质量分数为13.97~20.37 mg·kg^(-1);Cu元素呈波动下降的趋势,总体质量分数为9.25~17.08 mg·kg^(-1);Zn元素整体表现为下降趋势,总体质量分数为21.88~49.07 mg·kg^(-1)。总多酚质量分数呈先下降后上升的趋势,总黄酮、槲皮素、山奈酚质量分数总体呈先上升后下降的趋势,且三者均在盛花期前后达到最高。对黄连木雄花序主要营养指标进行主成分分析并对其综合品质进行排序可以看出,黄连木雄花序最佳采收期为在4月11日—4月13日(盛花前期-盛花期),此时雄花序综合营养品质较佳。

收割时间与加工方式对天然牧草产品品质和体外消化率的影响

为探明呼伦贝尔地区适宜天然牧草收割时间以及青贮的可行性,在2022年的7月11日(T_(1)组)、7月16日(T_(2)组)、7月21日(T_(3)组)、7月26日(T_(4)组)和7月31日(T_(5)组)收割天然牧草,采用天然干燥、青贮发酵和人工干燥3种方式加工天然牧草,评价其发酵品质、营养品质和体外消化率。结果表明:5个时间收割调制的天然牧草青贮饲料发酵品质均较好,天然牧草青贮饲料T_(3)和T_(4)组乳酸(LA)和乙酸(AA)含量较高,pH值和氨态氮/总氮(NH3-N/TN)较低。青贮发酵组相较于天然干燥组,T_(2)、T_(3)、T_(4)和T_(5)组收割的天然牧草,粗蛋白质(CP)含量显著增加(P<0.05),可溶性碳水化合物(WSC)含量显著降低(P<0.05),中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量差异不显著(P>0.05);各个时间收割的天然牧草的干物质体外消化率(IVDMD)和粗蛋白质体外消化率(IVCPD)显著增加(P<0.05)。青贮发酵组、天然干燥组和人工干燥组中,T_(4)组收割天然牧草的CP含量均最高,NDF和ADF含量较低,IVDMD和IVCPD较高。天然牧草青贮饲料的营养品质和体外消化率高于天然干燥调制的干草,在7月26日收割的天然牧草青贮饲料品质最好,建议在7月下旬中期收割天然牧草并进行青贮。

基于主成分分析的通海乌天麻适宜采收期研究

【目的】为通海天麻质量评价标准和最佳采收期研究提供理论支撑。【方法】通过HPLC测定通海5个采收期的天麻有效成分天麻素、对羟基苯甲醇、巴利森苷A、巴利森苷B、巴利森苷C和巴利森苷E含量,结合天麻产量、蛋白质与多糖含量,采用主成分分析法计算各指标权重,综合评价通海天麻的最佳采收期。【结果】1月和2月采收的天麻产量显著高于其他采收期;2月采收的天麻,其天麻素和对羟基苯甲醇总含量显著高于其他采收期;12月采收的天麻,其巴利森苷类物质总含量显著高于其他采收期;10月、11月和1月采收的天麻,其蛋白质含量显著高于其他采收期;12月和1月采收的天麻,其多糖含量显著高于其他采收期。主成分分析结果显示:产量、巴利森苷类和多糖因子权重高于天麻素和对羟基苯甲醇,蛋白质因子权重与对羟基苯甲醇相近。12月采收期综合得分最高,为0.603。【结论】12月采收通海天麻最佳,在天麻质量评价上应重视巴利森苷类、多糖和蛋白质的含量。

播种期及收获期对饲用小黑麦生产性能和营养品质的影响

为探明适宜宁夏半干旱区小黑麦(Triticosecale Wittmack)生产的播种期和刈割时期,以宁夏饲用小黑麦主推品种‘晋饲草1号’为研究材料,设置了3个小黑麦播种时期(S)和2个刈割时期(H),共6个处理,开展不同播种期和收获期对牧草生产性能和营养品质的影响研究,并应用主成分分析进行综合评价。结果表明,小黑麦的株高和叶面积随着播种期和收获期的延后显著增高(P<0.05);小黑麦干草产量和粗蛋白产量随着播种期的延后呈先增加后下降的趋势,小黑麦干草产量最大的处理为S2H2(9 665.74 kg·m^(-2)),粗蛋白产量最大的处理为S2H1,达881.15 kg·hm^(-2);不同播种期及收获期显著影响小黑麦营养品质(P<0.05),粗蛋白含量最高的为S2H2(10.18%),S1H2的相对饲喂价值最大。主成分分析综合排名第一的为S2H2(播种时间为9月20日,收获时间为灌浆期),是均衡饲用小黑麦产量和营养的理想组合,可作为宁夏雨养区饲用小黑麦播种和收获的参考依据。

不同采收期“卡罗拉”月季切花贮藏效果比较

目的为了延长月季切花“卡罗拉”的贮藏期,选取合适的采收期进行贮藏至关重要。方法分别以提前4 d采收(1级)、提前2~3 d采收(2级)、提前1 d采收(3级)、当天采收(4级)的月季切花“卡罗拉”为试材,于4℃下贮藏20 d,定期观察贮藏及瓶插期间鲜切花品质的变化。结果与其他采收期月季切花相比,2级月季切花乙烯生成速率偏低,贮藏15 d前,2级月季切花在一定程度上呼吸强度较低,丙二醛含量整体呈现较低趋势。在贮藏20 d瓶插8 d时,2级月季切花花朵直径偏大,可维持花朵较高的开放程度,花朵萎蔫指数、腐烂指数、质量损失率仅为40.66%、82.22%、11%,均低于其他采收期的月季切花;色差中L*值较高,b*值较低,表明2级月季切花颜色较为鲜亮,有效延缓了黄化现象。结论经过1d物流运输及20 d左右的贮藏条件下存放时,提前2~3 d采收(2级)的月季切花可维持较好的品质及观赏价值。

不同采收期新疆疏花蔷薇果化学成分的积累规律分析

采用紫外可见分光光度法测定了不同采收期新疆疏花蔷薇果中总多酚、总黄酮、总多糖、总有机酸和总氨基酸的含量,并通过主成分分析、聚类分析和相关性分析探究了各成分的动态积累规律。结果表明,不同采收期疏花蔷薇果中总多酚、总黄酮、总多糖、总有机酸、总氨基酸的含量呈现一定的波动趋势,样品S6中总多酚、总黄酮含量最高,分别为113.12 mg·g^(-1)、141.47 mg·g^(-1);样品S7中总多糖、总有机酸、总氨基酸含量最高,分别为304.37 mg·g^(-1)、25.43 mg·g^(-1)、19.13 mg·g^(-1);主成分PC1、PC2的累积方差贡献率为91.024%;不同采收期疏花蔷薇果的综合得分排名顺序为:S6>S7>S5>S3>S2>S1>S4;根据聚类分析可将不同采收期疏花蔷薇果分为3类,与主成分分析结果基本一致;疏花蔷薇果的适宜采收期为9月中旬。

不同采收期疏花蔷薇果成分积累及抗氧化活性研究

研究不同采收期疏花蔷薇果(Fructus Rosae Laxae,FRL)中主要化学成分的积累量与其体外抗氧化活性的相关性,确定其最佳采收期。采用高效液相色谱法(HPLC)测定不同采收期FRL中5种主要成分的含量,并考察其体外抗氧化活性,通过聚类分析、相关性分析和主成分分析对数据进行统计分析。结果表明:不同采收期FRL中椴树苷、紫云英苷、异槲皮苷、鞣花酸、没食子酸的质量分数范围依次为51.54〜854.10μg/g、11.39〜255.67μg/g、0.23〜1.18 mg/g、0.08〜5.53 mg/g和3.13〜8.29 mg/g,其均具有较好的抗氧化作用。相关性分析显示,紫云英苷、异槲皮苷、没食子酸和鞣花酸的含量与清除DPPH自由基和还原Fe^(3+)活性显著相关(P<0.05);主成分分析结果表明,不同采收期FRL的综合评分为S2>S1>S3>S4>S5>S6>S7;聚类分析结果与主成分分析结果一致,其最佳采收期为7月中旬。