Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios

Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.

Effects of Soil Fertility and Atmospheric CO_2 Enrichment on Leaf, Stem and Root Dark Respiration of Populus tremuloides

An open-top chamber experiment was conducted at the University of Michigan Biological Station near Pellston, Michigan, USA, to study the effects of soil fertility and CO2 on leaf, stem and root dark respiration (Rd) of Populus tremuloides. Overall, area-based day-time leaf Rd (Rda) was significantly greater at elevated than at ambient CO2 in high-fertility soil, but not in low-fertility soil. Mass-based leaf Rd (Rdm) was overall greater for high- than for low-fertility soil grown trees at elected, but not at ambient CO2. Nighttime leaf Rd. and Rdm were unthected by soil fertility or CO2, nor was stem Rda, which ranged from 1.0 to 1.4 μmol m-2 s-1 in the spring and 3.5 to 4.5 μmol m-2 s-1 in the summer. Root Rda. was significantly higher in high- than in low-fertility soil, but was unaffected by CO2. Since biomass production of P. tremuloides will be significantly greater at elevated CO2 while specific Rd will either increase or remain unchanged, we predict that carbon loss to the atmosphere through respiration from this ecologically important species would increase at higher CO2. Soil fertility would also interact with elevated CO2 in affecting the carbon flow in the plant-soil-air system.

Study on the Relationship of Seedling Density and Line Spacing to Leaf-stem Ratio, DW/FW Ratio and Grass Yield of Forage Sweet Sorghum

[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.

直立堤前stem波的分布规律及对工程的影响

当波浪沿直立堤以小于某临界角度入射时,将形成沿堤增长的stem波,目前国内外对stem波的研究较少且停留在理论阶段。以某直立堤台风破坏复演的物模试验为例,结合国内外研究成果,对stem波的产生条件、特征以及对工程的影响进行探讨。结果表明:1)stem波的波高和波宽均在沿堤传播中逐渐增大,沿堤比波高的增长呈现前快后慢的特点;2)不同入射波高和波向对于stem波的特征影响较大,详细的规律仍待进一步研究;3)stem波可对工程中直立堤造成蛇行破坏或对端部斜坡衔接段造成破坏,工程规划和结构选型应避免类似布置,宜采用三维物理模型试验验证stem波作用下结构的安全性。目前行业规范未涉及stem波相关内容,本研究成果可为工程设计提供参考。

Synergistic effects of ginseng stem and leaf-extracted ginsenoside and choline on improving learning and memory in rats Association verification experiment in animals with multiple learning and memory disorders

BACKGROUND： Ginsenoside extracted from the stem and leaf of ginseng （GSL） and choline have both been shown to improve learning and memory functions; however, further studies are needed to understand the synergistic effects of a combination of both. OBJECTIVE： To verify the combined improved synergistic effects of GSL and choline on learning and memory disorders in rats. DESIGN： Control observation. SETTING： Taishan Medical College. MATERIALS： A total of 150 male Kunming mice weighing （204-2） g and 40 healthy male Wistar rats weighing （2204-20） g were provided by the Experimental Animal Department of Jilin University. Animal experimentation received confirmed consent from the local ethic committee. GSL was provided by the Department of Chemistry, Norman Bethune Medical University, and choline was provided by the Third Experiment Factory, Shanghai. METHODS： This study was performed at the Life Science Institute, Taishan Medical College from October 2006 to February 2007. ① Scopolamine-induced learning and memory disorders in rats： Forty rats were randomly divided into control group, model group, combination group （400 mg/kg GSL ＋ 200 mg/kg choline）, GSL （400 mg/kg） group, and choline （200 mg/kg） group, 8 rats/group. Rats were perfused and administrated in the morning, once a day for 14 successive days. Rats in the control group and model group were perfused with 20 mL/kg distilled water and underwent Morris water maze spatial resolution test 1 hour after perfusion on the 10m, 11m, and 12m days after administration. Rats also underwent passive step-down avoidance test 1 hour after reperfusion on the 13m and 14m days after administration. Thirty minutes prior to experimentation, rats in the remaining three groups were intraperitoneally （i.p） injected with 2 mg/kg scopolamine, and rats in the control group were i.p. injected with 2 mL/kg saline. ② Scopolamine-induced learning disorder and memory acquired disorder in mice： Fifty mice were randomly divided into control group, model group, combination group （400 mg/kg GSL ＋200 mg/kg choline）, GSL （400 mg/kg） group, and choline （200 mg/kg） group, with 10 mice/group. Mice were perfused and administrated in the morning, once a day for 9 successive days. Mice in the control group and model group were perfused with 20 mL/kg distilled water and underwent passive step down avoidance test 1 hour after reperfusion on the 8th and 9th day after administration. Twenty minutes prior to training, mice in the remaining three groups were i.p. injected with 2 mg/kg scopolamine, and mice in the control group were i.p. injected with 10 mL/kg saline. ③ Sodium nitrite-induced memory consolidation disorder in mice： Grouping, administration, and testing were the same as mentioned above. After training, mice in the remaining three groups were immediately subcutaneously injected with 120 mg/kg sodium nitrite, and mice in the control group were subcutaneously injected with 20 mL/kg saline. ④ Ethanol-induced memory reconsolidation disorder in mice： Grouping, administration, and testing were the same as mentioned above. At 24 hours after training and 20 minutes before retraining, mice in the remaining four groups were perfused with 10 mL/kg ethanol （0.3 volume fraction）, and mice in the control group were perfused with 10 mL/kg saline. MAIN OUTCOME MEASURES： Synergistic effects of GSL and choline on learning and memory deficits induced by scopolamine, sodium nitrite, and ethanol in experimental animals. RESULTS： All 40 rats and 150 mice were included in the final analysis. ① Synergistic effects of GSL and choline on learning and memory disorders induced by scopolamine in rats： During passive step-down avoidance and Morris water maze spatial resolution tests, the number of error responses and length of maze training in the model group were significantly greater than in the control group （P 〈 0.01）; while the number of error responses and length of maze training in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combining administration, which suggests that the combination of GSL and choline had synergistic effects. ② Synergistic effects of GSL and choline on learning disorder and memory-acquired disorder induced by scopolamine in mice： During passive step-down avoidance test, the number of error responses in the model group were significantly greater than in the control group （P 〈 0.01 ）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combining administration, which suggests GSL and choline had synergistic effects. ③ Synergistic effects of GSL and choline on memory sodium nitrate-induced consolidation disorder in mice： During passive step down avoidance test, the number of error responses in the model group were significantly less than in the control group （P 〈 0.01 ）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combined administration, which suggests GSL and choline had synergistic effects. ④ Synergistic effects of GSL and choline on ethanol-induced memory reconsolidation disorder in mice： During passive step down avoidance test, the number of error responses in the model group were significantly greater than in the control group （P 〈 0.01）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combined administration, which suggests GSL and choline had synergistic effects. CONCLUSION： GSL and choline have synergistic effects on learning and memory functions.

Determination of the Photoperiod-Sensitive Inductive Phase in Maize with Leaf Numbers and Morphologies of Stem Apical Meristem

It is vital to determine the effective photoperiods of maize for making full use of tropical germplasm, which is the foundation for determining the effect of latitude and planting date on the development of photoperiod-sensitive maize cultivars. The objective of this study is to determine the photoperiod-sensitive inductive phase using reciprocal transfer between long- day （LD） （15 h d^-1） and short-day conditions （SD） （9 h d^-1）. For Huangzao 4 and CML288, days to tassel and pollen shedding were recorded, and stem apical meristems （SAM） were observed by a laser scanning confocal microscope. The results show that the seedlings are insensitive to photoperiod when they are very young （juvenile）. However, after this period, LD delays flowering and increases the leaf numbers below the inflorescence, and the length of the interval of the photoperiod-sensitive inductive phase is longer under LD conditions than under SD conditions. Transferred from SD to LD, plants show a sudden decrease in leaf numbers once sufficient SD has been received for flower commitment. While transferred from LD to SD, plants have a continuous increase in leaf numbers during the photoperiod sensitive inductive phase under LD conditions. At the same time, when plants are competent to flowers, the obvious morphology is the elongation of maize SAM. There is an obvious variance of the photoperiod sensitive phase under LD and SD conditions in different maize.

Effect of nitrogen and phosphorus addition on leaf nutrient concentrations and nutrient resorption efficiency of two dominant alpine grass species

Nitrogen(N)and phosphorus(P)are two essential nutrients that determine plant growth and many nutrient cycling processes.Increasing N and P deposition is an important driver of ecosystem changes.However,in contrast to numerous studies about the impacts of nutrient addition on forests and temperate grasslands,how plant foliar stoichiometry and nutrient resorption respond to N and P addition in alpine grasslands is poorly understood.Therefore,we conducted an N and P addition experiment(involving control,N addition,P addition,and N+P addition)in an alpine grassland on Kunlun Mountains(Xinjiang Uygur Autonomous Region,China)in 2016 and 2017 to investigate the changes in leaf nutrient concentrations(i.e.,leaf N,Leaf P,and leaf N:P ratio)and nutrient resorption efficiency of Seriphidium rhodanthum and Stipa capillata,which are dominant species in this grassland.Results showed that N addition has significant effects on soil inorganic N(NO_(3)^(-)-N and NH_(4)^(+)-N)and leaf N of both species in the study periods.Compared with green leaves,leaf nutrient concentrations and nutrient resorption efficiency in senesced leaves of S.rhodanthum was more sensitive to N addition,whereas N addition influenced leaf N and leaf N:P ratio in green and senesced leaves of S.capillata.N addition did not influence N resorption efficiency of the two species.P addition and N+P addition significantly improved leaf P and had a negative effect on P resorption efficiency of the two species in the study period.These influences on plants can be explained by increasing P availability.The present results illustrated that the two species are more sensitive to P addition than N addition,which implies that P is the major limiting factor in the studied alpine grassland ecosystem.In addition,an interactive effect of N+P addition was only discernable with respect to soil availability,but did not affect plants.Therefore,exploring how nutrient characteristics and resorption response to N and P addition in the alpine grassland is important to understand nutrient use strategy of plants in terrestrial ecosystems.

Effects of ginsenoside of stem and leaf combined with choline on learning and memory ability of rat models with Alzheimer diseases

BACKGROUND： Central adrenergic nerve and 5-serotonergic nerve can influence central cholinergic nerve on learning and memory and make easy for study; however, ginsenoside of stem and leaf （GSL） can improve functions of central adrenergic nerve; moreover, 5-serotonergic nerve and the combination with choline can produce synergistic effect and enhance learning and memory ability so as to improve learning and memory disorder of patients with Alzheimer disease （AD）. OBJECTIVE ： To observe the effects of GSL combining with choline on learning and memory of AD model rats DESIGN ： Randomized grouping design and controlled animal study SETIING ： Department of Pharmacology, Taishan Medical College MATERIALS ： The experiment was carried out in the Pharmacological Department of Medical College of Jilin University from October 1996 to January 1997. Forty healthy male Wistar rats of clean grade were randomly divided into 5 groups, including sham-injury group, model group, GSL group, choline group and combination group, with 8 rats in each group. Main medications： GSL with the volume more than 92.8% was provided by Department of Chemistry, Norman Bethune Medical College of Jilin University. Panaxatriol, the main component, was detected with thin layer scanning technique and regarded as the index of GSL quality [（55±1）%, CV= 2%, n = 5]. Choline was provided by the Third Shanghai Laboratory Factory. METHODS ： 150 nmol quinolinic acid was used to damage bilateral Meynert basal nuclei of adult rats so as to establish AD models. Rats in GSL, choline and combination groups were intragastric administrated with 400 mg/kg GSL, 200 mg/kg choline （20 mL/kg）, and both respectively last for 17 days starting from two days before operation. Rats in sham-injury group and model group were perfused with the same volume of distilled water once in each morning for the same days. （1） Passive avoidance step-down test： Five minutes later, rats jumped up safe platform when they were shocked with 36 V alternating current. If rats jumped down from the platform and the feet touched railings, the response was wrong. Numbers of wrong response were recorded within 3 minutes, and then the test was redone after 24 hours. （2） Morris water-maze spatial localization task： Swimming from jumping-off to platform directly was regarded as right response. Additionally, 4 successively right responses were regarded as the standard. Each rat was trained 10 times a day with 120 s per time for 3 successive days. The interval was 30 s. Three days later, numbers of right response were recorded. The training times were increased to 30 for unlearned rats. （3） Measurement of activity of choline acetylase in cerebral cortex： Rats were sacrificed at 17 days after operation to obtain cerebral cortex to measure activity of choline acetylase with radiochemistry technique. （4） Synergistic effect： It was expressed as Q value： Q value = factual incorporative effect/anticipant incorporative effect; Q ≥ 1 was regarded as synergistic effect. Anticipant incorporative effect = （EA＋EB-EA·EB）, EA and EB were single timing effect, respectively in GSL group and choline group. E（step-down test and Morris water maze test） = （x in model group - factual value in medicine groups）/x in model group; E （activity of choline acetylase） = （factual value in medicine groups -xin model group）/xin model group. MAIN OUTCOME MEASURES ： （1） Passive avoidance step-down test and Morris water-maze spatial localization task in the study of learning and memory; （2） activity of choline acetylase. RESULTS ： All 40 rats were involved in the final analysis. （1） Passive avoidance response： At learning phase on first day and retesting phase on the next day, numbers of wrong responses within 3 minutes were more in model group than sham operation group, and there was significant difference [（5.88±1.46）, （2.25±0.87） times; （2.63±1.06）, （0.50±0.53） times; P 〈 0.01]; numbers of wrong responses within 3 minutes were less in combination group than model group, and there was significant difference [learning phase： （1.12±0.83）, （5.88±1.46） times; retesting phase： （0.38±0.74）, （2.63±1.06）times, P 〈 0.01]; moreover, effect was stronger than that in GSL group and choline group. The Q value was 1.07 and 1.59, respectively and it showed synergistic effect. Spatial localization task： Training times were more in model group than sham operation group, and there was significant difference [（2.9±2.5）, （12.6±3.5） times; P 〈 0.01]. Training times were less in combination group than model group, and there was significant difference [（11.8±2.4）, （27.9±2.5） times, P 〈 0.01]; moreover, effect was stronger than that in GSL group and choline group. The Q value was 1.07 and it showed synergistic effect. （3） Activity of choline acetylase： Activity was lower in model group than sham operation group, and there was significant difference [（30.56±8.33）, （61.11 ±8.33） nkat/g; P 〈 0.01]. Activity was higher in combination group than model group and there was significant difference [（50.00±8.33）, （30.56±8.33） nkat/g, P 〈 0.01];moreover, effect was stronger than that in GSL group and choline group. The Q value was 1.5 and it showed synergistic effect. CONCLUSZON： GSL in combination with choline can synergically improve the disorder of learning and memory of AD model rats. Its mechanism may be involved in enhancing the function of central cholinergic system.

Pretreatment with scutellaria baicalensis stem-leaf total flavonoid prevents cerebral ischemia-reperfusion injury

Pretreatment with scutellaria baicalensis stem-leaf total flavonoid has protective effects against ischemia and attenuates myocardial ischemia-reperfusion injury. In this study, rats were given scutellaria baicalensis stem-leaf total flavonoid intragastrically at 50, 100, and 200 mg/kg per day for 7 days before focal cerebral ischemia-reperfusion injury models were established using the suture method. We then determined the protective effects of scutellaria baicalensis stem-leaf total flavon- oid pretreatment on focal cerebral ischemia-reperfusion injury. Results showed that neurological deficit scores increased, infarct volumes enlarged, apoptosis increased and Bcl-2 and Bax protein expression were upregulated at 24 hours after reperfusion. Pretreatment with scutellaria baicalensis stem-leaf total flavonoid at any dose lowered the neurological deficit scores, reduced the infarct volume, prevented apoptosis in hippocampal cells, attenuated neuronal and blood-brain barrier damage and upregulated Bcl-2 protein expression but inhibited Bax protein expression. Doses of 100 and 200 mg/kg were the most efficacious. Our findings indicate that pretreatment with scutel- laria baicalensis stem-leaf total flavonoid at 100 and 200 mg/kg can improve the neurological func- tions and have preventive and protective roles after focal cerebral ischemia-reperfusion injury.

Pretreatment with scutellaria baicalensis stem-leaf total flavonoid protects against cerebral ischemia/reperfusion injury in hippocampal neurons

Previous experimental studies have shown that cerebral infarction can be effectively reduced following treatment with scutellaria baicalensis stem-leaf total flavonoid （SSTF）. However, the mechanism of action of SSTF as a preventive drug to treat cerebral infarction remains unclear. In this study, Sprague-Dawley rats were pretreated with 50, 100, 200 mg/kg SSTF via intragastric ad- ministration for 1 week prior to the establishment of focal cerebral ischemia/reperfusion injury. The results showed that pretreatment with SSTF effectively improved neurological function, reduced brain water content and the permeability of blood vessels, ameliorated ischemia-induced morphology changes in hippocampal microvessels, down-regulated Fas and FasL protein expression, elevated the activity of superoxide dismutase and glutathione peroxidase, and decreased malondialdehyde content. In contrast to low-dose SSTF pretreatment, the above changes were most obvious after pretreatment with moderateand high-doses of SSTF. Experimental findings indicate that SSTF pretreatment can exert protective effects on the brain against cerebral ischemia/reperfusion injury. The underlying mechanisms may involve reducing brain water content, increasing microvascular recanalization, inhibiting the apoptosis of hippocampal neurons, and attenuating free radical damage.

Scutellaria baicalensis stem-leaf total flavonoid reduces neuronal apoptosis induced by amyloid beta-peptide (25-35)

Scutellaria baicalensis stem-leaf total flavonoid might attenuate learning/memory impairment and neuronal loss in rats induced by amyloid beta-peptide. This study aimed to explore the effects of Scutellaria baicalensis stem-leaf total flavonoid on amyloid beta-peptide-induced neuronal apoptosis and the expression of apoptosis-related proteins in the rat hippocampus. Male Wistar rats were given intragastric administration of Scutellaria baicalensis stem-leaf total flavonoid, 50 or 100 mg/kg, once per day. On day 8 after administration, 10 pg amyloid beta-peptide （25-35） was injected into the bilateral hippocampus of rats to induce neuronal apoptosis. On day 20, hippocampal tissue was harvested and probed with the terminal deoxyribonucleotidyl transferase-mediated biotin-16-dUTP nick-end labeling assay. Scutellaria baicalensis stem-leaf total flavonoid at 50 and 100 mg/kg reduced neuronal apoptosis induced by amyloid beta-peptide （25-35） in the rat hippocampus. Immunohistochemistry and western blot assay revealed that expression of the pro-apoptotic protein Bax, cytochrome c and caspase-3 was significantly diminished by 50 and 100 mg/kg Scutellaria baicalensis stem-leaf total flavonoid, while expression of the anti-apoptotic protein Bcl-2 was increased. Moreover, 100 mg/kg Scutellana baicalensis stem-leaf total flavonoid had a more dramatic effect than the lower dosage. These experimental findings indicate that Scutellaria baicalensis stem-leaf total flavonoid dose-dependently attenuates neuronal apoptosis induced by amyloid beta-peptide in the hippocampus, and it might mediate this by regulating the expression of Bax, cytochrome c, caspase-3 and Bcl-2.

Antibacterial Activity of Psidium guajava Leaf and Stem Bark Extracts on Selected Bacteria in Ugbokolo, Benue State, Nigeria

Aim: In recent years, there has been a growing interest in researching and developing new antimicrobial agents from various sources to combat microbial resistance. The study was aimed at determining the phytochemical constituents and in vitro antibacterial activity of methanol and aqueous extracts of Psidium guajava leaves and stem bark on Escherichia coli, Salmonella typhi, Staphylococcus aureus and Proteus sp. in Ugbokolo, Nigeria. Materials and Methods: The phytochemical screening of the plant materials for various bioactive components was conducted between July and December, 2019 using standard laboratory techniques. The extracts were purified using column chromatography. The identity of the test isolates were confirmed using morphological characteristics, gram stain, motility and appropriate biochemical tests such as indole, catalase, coagulase, triple sugar iron agar. The susceptibility of the isolates to each bioactive component was determined using the agar well diffusion method. The broth dilution method was employed for the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts. Results: The result of the study showed the presence of phenol, tannins, flavonoids and saponins as bioactive compounds. The antibacterial susceptibility of the isolates to aqueous and methanol extracts of leaf and stem bark of Psidium guajava varied significantly (P Staphylococcus aureus was the most susceptible isolate at 200 mg/ml concentration with average zone of inhibition of 13.05 mm for leaf extract and 15.34 mm for stem bark extract. Proteus sp. is the least susceptible with average zone of inhibition of 8.88 mm for the leaf extract and 12.36 mm for the stem bark extract respectively. Minimum Inhibitory Concentration and Minimum Bactericidal Concentration of aqueous and methanol extract of P. guajava leaf and stem bark showed that dilutions of various concentrations of aqueous and methanol extracts can inhibit and/or kill the isolates. Lower MIC (3.125 mg/ml) was shown by methanol extract than aqueous extract. MBC of methanol extract ranges between 6.25 - 25.0 mg/ml. Statistical analysis of the result showed methanol extract is more effective than aqueous extract while the stem bark of the plant showed higher efficacy than the leaf. Conclusion: The findings of the study imply that the extract of Psidium guajava has shown promising properties against tested microorganisms. Further study of the extract is therefore recommended.

The Variety Screening of Green-stem Non-heading Chinese Cabbage and Dark-green-leaf Non-heading Chinese Cabbage Tolerant to Heat

[Objectives] Introducing and screening leaf vegetable varieties tolerant to heat and humidity has great significance to ensure balanced supply of vegetables in summer and autumn in Hainan Province. [Methods] On the basis of the introduction of green-stem non-heading Chinese cabbage and dark-green-leaf non-heading Chinese cabbage varieties, the varieties tolerant to heat and humidity were identified by the investigation of agronomic traits and evaluation of heat injury index. [Results] The data analysis results showed that four green-stem non-heading Chinese cabbage varieties including Huaguan Qingcaigeng F_1, Zhongguan Qinggeng, Hanshen No. 1 Qinggengcai F_1 and Huaxiawang Piaocai have the characteristics of strong tolerance to heat and high yield, and four dark-green-leaf non-heading Chinese cabbage varieties including Baimeigui, Heijingang, Xiaxue Naibaicai and Siji Baicai have the characteristics of strong tolerance to heat and high yield. [Conclusions] These eight leaf vegetable varieties are suitable for popularization in summer and autumn in Hainan Province.

不同叶果比对设施‘红美人’杂柑秋梢叶片生理生化特征的影响

为探究不同叶果比(leaffruitratio,LFR)对设施柑橘秋梢叶片生理生化特征的影响,以设施栽培‘红美人’杂柑为试材,设置高(LFR=100)、中(LFR=80)、低(LFR=60)3个叶果比,测定秋梢叶片中矿质元素、碳氮代谢物、碳氮代谢的关键酶、抗氧化酶活性等生理指标的变化。结果显示,LFR80和LFR100秋梢叶片的磷、钾、镁、淀粉含量较高;丙二醛、脯氨酸、抗坏血酸含量较低;β-淀粉酶、硝酸还原酶、谷氨酰胺合成酶和抗坏血酸过氧化物酶的活性较高;LFR80和LFR100秋梢叶片整体养分含量充足,受胁迫程度较低。结果表明,设施栽培‘红美人’杂柑的叶果比控制在80~100有利用于平衡营养生长和生殖生长,延缓叶片衰老,维持树势强健。

银州柴胡茎叶的发育解剖学研究

以伞形科柴胡属植物银州柴胡(Bupleurum yinchowense)为研究对象,采用石蜡切片结合组织透明法对银州柴胡茎和叶的结构发育进行研究,以期为柴胡属植物的分类和鉴定提供科学依据。结果显示,银州柴胡茎的发育可分为原分生组织、初生分生组织、初生生长以及次生生长4个阶段,茎尖顶端分生组织分为原套和原体;茎的初生分生组织包括原表皮、基本分生组织和原形成层,原表皮发育为表皮,基本分生组织发育为皮层、髓射线和髓,原形成层发育为维管束(由初生韧皮部、形成层和初生木质部组成);茎的初生结构包括表皮、皮层和维管柱,维管柱包括维管束、髓射线和髓;银州柴胡茎有微弱的次生生长,髓射线位置细胞的细胞壁常明显加厚。叶的发育分为原分生组织、初生分生组织和初生生长3个阶段;叶为异面叶,上下表皮由一层细胞组成,有气孔分布,为无规则型;栅栏组织由1层细胞组成,海绵组织由6~8层细胞组成;叶脉维管束为外韧维管束,其上下方均未观察到纤维分布;茎棱角的皮层、初生韧皮部、髓周围以及叶脉韧皮部均分布有分泌道;叶脉维管束木质部上方的组织中,分泌道有或无;银州柴胡茎和叶分泌道均为裂生型。结果表明,银州柴胡茎和叶的结构特点明显,有别于其他柴胡属植物,可为柴胡属药用植物的分类和鉴定提供科学依据。

鱼腥草叶斑病及茎斑病病原菌的分离与鉴定

为了明确引起四川省广汉市鱼腥草新型叶斑及茎斑类病害的病原菌种类,为该病的科学防治提供理论依据,对采自广汉市的鱼腥草病茎叶通过组织消毒分离、离体接种、形态学观察与基于核糖体转录间隔区(ITS)、延长因子(tef1)、钙调蛋白(cal)和组蛋白(his3)基因的分子鉴定进行病原菌的分离鉴定。结果表明,病原菌菌丝呈灰白色到浅褐色,其分生孢子器可产生纺锤形到椭圆形的α型分生孢子以及丝状或钩状β型分生孢子。多基因联合系统发育分析表明,病原菌在大豆间座壳(Diaporthe sojae)和菜豆间座壳(D.phaseolorum)分枝外单独聚为一枝,并且3枝一起聚为一个大枝,因此建议成立一个新种—鱼腥草间座壳(D.houttuynia)来容纳此类病菌。结合形态学和分子鉴定结果,将引起广汉市鱼腥草新型叶斑及茎斑类病害的病原菌鉴定为鱼腥草间座壳(D.houttuynia)。

黄芪茎叶提取物对仔猪生长性能、养分表观消化率及免疫指标的影响

文章旨在探究添加不同水平黄芪茎叶提取物对断奶仔猪生长性能、养分表观消化率及免疫机能的影响。试验将120头健康的体重(25±0.5)kg的“杜×长×大”三元杂交仔猪随机分成4组,每组3个重复,每个重复组10头,试验分别在基础日粮中添加0(1组)、1.0%(2组)、1.5%(3组)、2.0%(4组)黄芪茎叶提取物,预饲期10d,整个试验为期56d。结果表明:(1)试验3、4组平均日增重较1组分别显著提高11.6%、10.1%(P <0.05),其料重比较1组分别显著降低9.4%、7.0%(P <0.05);(2)试验3、4组粪便中的粗蛋白质、粗脂肪、粗纤维的养分表观消化率较1组分别显著提高10.9%、10.8%、10.8%、11.2%、16.5%、15.9%(P <0.05);(3)试验3、4组血清中IgA、IgG、IL-2含量较1组分别显著提高10.8%、11.7%、12.0%、13.7%、22.9%、25.1%(P <0.05),其血清中TNF-α含量较1组分别显著降低20.8%、22.1%(P <0.05)。综上所述,添加1.5%黄芪茎叶提取物可以提高“杜×长×大”二元杂交仔猪的生长性能、养分表观消化率及免疫机能。

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,R^(2)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)与氮含量决定系数R^(2)=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降低到0.214,抽穗期的NRMSE提升最大,从0.201降低到0.128。对茎秆氮含量,全生育期的NRMSE从0.443降低到0.400,抽穗期的NRMSE变化最大,从0.323降低到0.268。在全生育期,结合SPAD值的DNN模型对叶片(R^(2)=0.782、NRMSE=0.214)和茎秆(R^(2)=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。

莴笋红叶基因图位克隆及分子标记开发

【目的】研究莴笋叶色变异的遗传基础,加速莴笋新品种育种进程,提高育种效率。【方法】通过构建红叶和绿叶莴笋杂交群体,分析遗传规律,利用混池分组分析法(BSA-seq)和图位克隆法精细定位并克隆了莴笋红叶基因Lactuca sativa Red Leaf 1(LsRL1),根据变异位点设计了分子标记用于红叶莴笋分子标记辅助育种。【结果】遗传分析结果显示F2分离群体中红叶个体与绿叶个体的分离比为3∶1,说明研究中莴笋叶色表型受一个基因控制,且红叶相对于绿叶为显性性状。混池分组分析法(BSA-seq)将莴笋叶色基因LsRL1初步定位在莴笋第5染色体336.00 Mb到339.64 Mb的范围内。利用图位克隆的方法进一步将LsRL1基因的范围缩小至2个Indel分子标记ls06和ls12之间的85.17 kb区间内,这一区间内包含2个基因LOC111892298和LOC111892911。亲本间差异位点分析将LsRL1的候选基因确定为LOC111892911,该基因在拟南芥中的同源基因编码一个bHLH转录因子,参与花青素合成途径的调控。【结论】基于LsRL1基因在2个亲本间的插入缺失变异,我们开发了一个可用于红叶莴笋分子标记辅助育种的Indel标记,以加速红叶莴笋的育种进程。