海南橡胶林落叶特征研究

以海南幼龄和成龄橡胶林为对象,采用野外凋落框收集和关联分析等方法,研究2019年5月至2020年4月海南儋州区域橡胶林落叶特征和影响橡胶落叶的主要气候因子。研究结果表明:(1)海南橡胶林落叶产量呈"双峰"型动态变化,当年7月出现小峰,翌年3月出现最高峰;翌年2—4月为集中落叶期,该时期幼龄和成龄林分别占全年落叶总产量的73.04%和70.61%;成龄林落叶产量显著高于幼龄,增幅为14.77%。冗余分析表明,月均温度与月落叶产量呈极显著负相关关系,解释度为49.9%,贡献率为58.6%;(2)幼龄和成龄林间落叶C、N、P、K、Ca、Mg含量月动态变化趋势相似,各元素含量在秋冬季呈下降趋势,而冬春季出现养分富集的现象,年均含量在成龄和幼龄林间差异不显著;(3)落叶养分归还量月动态与落叶产量动态变化相似,受落叶月产量影响较大,而归还量受落叶产量和养分含量共同影响,落叶归还量表现为C>N>K、Ca>Mg>P,成龄显著高于幼龄,各元素增幅分别为16.3%、17.1%、16.7%、27.4%、15.3%和17.7%;(4)幼龄林各元素养分利用效率总体高于成龄林,其中幼龄钾素养分利用效率显著高于成龄(P<0.05);(5)月均温度是影响2019—2020年海南儋州橡胶林落叶格局的主要气候因子。该研究成果可为海南橡胶割胶制度以及养分管理提供技术支撑。     

海南橡胶林落叶特征研究

以海南幼龄和成龄橡胶林为对象,采用野外凋落框收集和关联分析等方法,研究2019年5月至2020年4月海南儋州区域橡胶林落叶特征和影响橡胶落叶的主要气候因子。研究结果表明:(1)海南橡胶林落叶产量呈"双峰"型动态变化,当年7月出现小峰,翌年3月出现最高峰;翌年2—4月为集中落叶期,该时期幼龄和成龄林分别占全年落叶总产量的73.04%和70.61%;成龄林落叶产量显著高于幼龄,增幅为14.77%。冗余分析表明,月均温度与月落叶产量呈极显著负相关关系,解释度为49.9%,贡献率为58.6%;(2)幼龄和成龄林间落叶C、N、P、K、Ca、Mg含量月动态变化趋势相似,各元素含量在秋冬季呈下降趋势,而冬春季出现养分富集的现象,年均含量在成龄和幼龄林间差异不显著;(3)落叶养分归还量月动态与落叶产量动态变化相似,受落叶月产量影响较大,而归还量受落叶产量和养分含量共同影响,落叶归还量表现为C>N>K、Ca>Mg>P,成龄显著高于幼龄,各元素增幅分别为16.3%、17.1%、16.7%、27.4%、15.3%和17.7%;(4)幼龄林各元素养分利用效率总体高于成龄林,其中幼龄钾素养分利用效率显著高于成龄(P<0.05);(5)月均温度是影响2019—2020年海南儋州橡胶林落叶格局的主要气候因子。该研究成果可为海南橡胶割胶制度以及养分管理提供技术支撑。     

海南植胶区不同群落结构林下生物多样性分析

通过样方调查的方法分析海南植胶区4种不同特点、不同气候带及不同地形的林下植被生物多样性。结果表明，4种植被林(包括幼龄橡胶林、老龄橡胶林、桉树人工林、天然次生林)中，物种数由高到低分别为老龄橡胶林(44种)＞幼龄橡胶林(41种)＞天然次生林(39种)＞桉树人工林(30种)；不同气候带林下物种组成及生物多样性指数差异较大，表现为湿润气候带以需水量大的草本植物，干旱半干旱地区以适应性强的植物为主，且湿润气候带的物种优势度指数和丰富度指数高于干旱、半干旱气候带，而多样性指数和均匀度指数则相反；其次，平原台地与山丘地区的4种群落类型下物种优势度λ均具有一定的差异，整体表现为天然次生林＞老龄橡胶林＞幼龄橡胶林＞桉树人工林。     

龙舌兰杂种11648生长周期叶片质量变化规律及割叶制度的研究

本文就广东湛江南部栽培的龙舌兰杂种11648(以下简称H.11648)进行生长周期叶片质量变化规律的研究,结果表明:(1)成龄麻的纤维拉力强度比幼龄麻和老龄麻高。成龄麻又以中层叶片较高。老龄麻叶轮间无显著差异;(2)6龄前的纤维率是随麻龄增加而提高。6龄后基本稳定。幼龄麻、成龄麻的纤维率由老叶到嫩叶逐轮提高;(3)开割标准以植后2～2年3个月较好。割叶周期以1年为好。割叶强度以留叶4轮为宜,初期和老龄麻适当多留。     

龙舌兰杂种11648生长周期叶片质量变化规律及割叶制度的研究

本文就广东湛江南部栽培的龙舌兰杂种11648(以下简称H．11648)进行生长周期叶片质量变化规律的研究，结果表明：(1)成龄麻的纤维拉力强度比幼龄麻和老龄麻高。成龄麻又以中层叶片较高。老龄麻叶轮间无显著差异；(2)6龄前的纤维率是随麻龄增加而提高。6龄后基本稳定。幼龄麻、成龄麻的纤维率由老叶到嫩叶逐轮提高；(3)开割标；隹以植后2～2年8个月较好。割叶周期以1年为好。割叶强度以留叶4轮为宜，初期和老龄麻适当多留。     

3个巴西橡胶树品种的死皮病调查

在现有割胶制度下对巴西橡胶树3个品种(热研8-79、热研7-33-97、PR107)的死皮病进行了调查。结果表明：这3个品种的幼龄树发病率和停割率从大到小依次为热研7-33-97(开割4年)＞ PR107(开割6年)＞热研8-79(开割3年),中龄树发病率和停割率从大到小依次为PR107(开割15年)＞热研7-33-97(开割8年)＞热研8-79(开割14年)。3个品种的中龄橡胶树比幼龄橡胶树的死皮病发病率、停割率和病情指数都有所上升。总体来看,对于幼龄橡胶树而言,肥水条件较好的地块,年干胶株产量高,发病率和停割率低;而中龄树除热研7-33-97表现出幼龄树的趋势外,其它2个品种(热研8-79和PR107)则干胶株产量高,发病率和停割率也高。绝大多数死皮病属割面干涸类型,少部分为褐皮病;褐皮病有一部分是一开始就发生的,多数是由割面干涸发展而来的。在停割至少1年之后,能够恢复排胶的死皮树比例较小,很少超过10%。在3个橡胶树品种中, PR107品种恢复排胶的比例最高,幼龄树和中龄树恢复率分别达8.70%和6.20%。     

海南儋州橡胶林生态系统碳贮量及分布规律研究

橡胶林生态系统碳贮量主要由土壤层、枯枝落叶层、林下植被层和乔木层组成。对海南儋州6个龄级(5、10、15、20、25、30年生)橡胶林样地的土壤层(0 cm-20 cm,20 cm-40 cm,40 cm-60 cm,60 cm-80 cm,80 cm-100 cm)、林下植被层、枯枝落叶层和乔木层样品进行了调查、采样,并对其有机碳含量进行室内测试分析,初步探得海南儋州橡胶林生态系统总碳贮量为851.3 t/hm²,碳贮量土壤层(536.9 t/hm²)＞乔木层( 306.8 t/hm²)＞枯枝落叶层(4.4 t/hm²)＞林下植被(3.2 t/hm²)。5、10、15、20、25、30年生橡胶林生态系统碳贮量在(75.7-152.7 )t/hm²之间变化,呈“双峰”趋势。     

老龄橡胶树不同器官含碳率分析

采用收获法测定与分析30 a老龄橡胶树不同器官含碳率.结果表明:(1)橡胶林地上部分各器官含碳率依次为:树叶(52.90％)＞树干(48.84％)＞侧枝(47.46％)＞树皮(46.20％)＞嫩枝(45.20％),其中树叶含碳率显著高于其它器官；橡胶林地面部分凋落物各组分的含碳率大小为,落果(55.30％)＞落叶(53...     

不同树龄橡胶树林地土壤有机碳含量与储量特征

研究幼林早期(2龄)、幼林晚期(7龄)、开割树(16龄)和老龄即将更新树(30龄)4种不同树龄橡胶树林地的土壤有机碳含量与储量特征.结果表明:(1)不同树龄橡胶树林地各土壤层次土壤有机碳含量变化不大,但普遍表现为表层土壤(0～15 cm土层)有机碳含量高于平均值,下层土壤(45～60cm土层)有机碳含量低于平均值,中间两层的(15～30cm土层、30～45 cm土层)变化不大,在平均值的上下浮动;(2)不同树龄橡胶树林地土壤有机碳含量介于6.03～7.78g/kg之间,相互间存在显著差异,高低排序为幼林晚期(7龄)老龄即将更新树(30龄)幼林早期(2龄)开割树(16龄);(3)胶林有机碳储量主要决定于其土壤有机碳含量和土壤容重,不同树龄橡胶树林地土壤有机碳储量介于61.33～74.29t/hm2之间.相互间存在差异,高低排序为老龄即将更新树(30龄)幼林晚期(7龄)幼林早期(2龄)开割树(16龄).     

滇东南植胶区2013/2014年冬春橡胶树寒害调研报告

选取不同环境(海拔、坡向,不同品种、不同树龄)的橡胶树对寒害状况进行实地走访调查,从降温过程、性质与特点及橡胶物候、品系(种)、割龄等方面对橡胶树寒害进行分析,结果显示：①以平流为主的混合型降温过程,是多次寒害累加受害的结果。②橡胶树割龄寒害症状从重到轻表现为失管胶林段(前2次寒害达4～6级的割林,受灾后疏于管理,长势弱恢复慢)＞老割林段(割龄21～30年)＞新割林段(割龄1～20年),橡胶树中幼林基本无寒害。主要查明2013/2014年冬春滇东南植胶区橡胶树寒害情况,总结抗寒植胶经验,提出抗寒植胶建议,为滇东南今后种好橡胶提供科学依据。     

Characterization of starches of proso,foxtail, barnyard,kodo, and little millets

Scanning electron microscope (SEM) pictures of small millet starch granules showed more large polygonal and few small spherical or polygonal granules. The granules of small millets resembled those of rice starch granules. The size of the starch granules ranged from 0.8–10 m. The size of the granules was larger in barnyard millet and smaller in proso millet. Several granules showed deep indentation caused by protein bodies. SEM of starch isolated from 24 hour-germinated kodo millet showed pitting or pinholes at some points due to the attack of amylases (preferentially on bigger granules). Brabender viscoamylograph studies on small millet starches revealed that the gelatinization temperatures ranged from 75.8 to 84.9 ^° C. Barnyard millet possessed lower amylograph viscosity, minimum breakdown, and relative breakdown values when compared to the other small millets.     

Effects of application of nitrogen fertilizer on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in perennial ryegrass/white clover pastures in south-western Victoria, Australia

Effects of timing and rate of N fertilizer application on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in herbage from perennial ryegrass/white clover pastures were studied at two sites in south-western Victoria, Australia. Nitrogen fertilizer (0, 15, 25, 30, 45 and 60 kg ha^–1) was applied as urea in mid-April, early May, mid-May, early June and mid-June 1996 to pastures grazed by dairy cows. At Site 1, N fertilizer resulted in a linear increase in P, K, S, Mg and Cl concentrations in herbage and a linear decrease in Ca concentration. For all times of application, concentrations of P, K, Ca, Mg and Cl in herbage increased by 0·0048, 0·08, −0·010, 0·0013 and 0·053 g kg^–1 dry matter (DM) per kg N applied respectively. For S concentration, maximum responses occurred in mid-May (0·012 g kg^–1 DM per kg N applied). At Site 2, N fertilizer resulted in a linear increase in P, S and Na concentrations in herbage, a linear decrease in Ca concentration and a curvilinear increase in K and Cl concentration. The maximum responses for P, S and K concentrations in herbage occurred for the N application in mid-June and were 0·015, 0·008 and 0·47 g kg^–1 DM per kg N applied respectively. For Cl concentration, the maximum response occurred for the N application in early June and was 0·225 g kg^–1 DM per kg N applied. Overall, applications of N fertilizer up to 60 kg ha^–1 did not alter herbage mineral concentration to levels that might affect pasture growth or animal health.     

Milling,functional and thermo-mechanical properties of wheat,rye, triticale,barley and oat

The milling potential of hulled barley, hulled oat, triticale, rye and wheat was studied using a long tempering process and a laboratory four-roller mill. Regardless of the investigated cereal, the results indicated a significant influence (p < 0.05) of volume per surface area ratio on the milling yield and ash contents of the flour. The lowest milling yield was obtained in case of hulled oat. Solvent retention capacity profiles were determined for all investigated whole cereals and flours for predicting the contribution of different polymers to the functionality of samples. For all solvents higher values were obtained for the whole cereals compared to the corresponding flour. Thermo-mechanical properties of the whole cereals and refined flours were also investigated. If in case of wheat the gluten proteins play an essential role on dough behaviour during kneading at 30 °C, in case of triticale, rye, hulled barley and hulled oat, the fibers play a major role as well. Thermo-mechanical properties of starch registered a large variation between cereals and/or flours. The lowest torque value corresponding to starch gelatinization (C3) was registered in case of the hulled oat flour, 1.92 Nm, while the highest value in case of rye flour, 2.65 Nm.     

Study of antimicrobial activity of aloevera, chitosan, and curcumin on cotton, wool, and rabbit hair

Aloevera, chitosan, and curcumin were applied in alone and in combination with each others on cotton, wool and rabbit hair by exhaustion method for the assessment of their antimicrobial activity. The antimicrobial activity of these natural ingredients was better in peroxide treated cotton, formic acid treated wool/rabbit hair fibrous substrates than their corresponding intact ones. Aloevera shown better antimicrobial activity than chitosan and curcumin when applied alone and its antimicrobial activity was enhanced by addition of both chitosan and curcumin. The application of aloevera+chitosan+curcumin combination on peroxide treated cotton and formic acid treated wool/rabbit hair fibrous substrate was fast up to twenty five washing cycles.     

Structure Elucidation of New Acetylated Saponins,Lessoniosides A,B, C,D, and E,and Non-Acetylated Saponins,Lessoniosides F and G,from the Viscera of the Sea Cucumber Holothuria lessoni

Sea cucumbers produce numerous compounds with a wide range of chemical structural diversity. Among these, saponins are the most diverse and include sulfated, non-sulfated, acetylated and methylated congeners with different aglycone and sugar moieties. In this study, MALDI and ESI tandem mass spectrometry, in the positive ion mode, were used to elucidate the structure of new saponins extracted from the viscera of H. lessoni. Fragmentation of the aglycone provided structural information on the presence of the acetyl group. The presence of the O-acetyl group was confirmed by observing the mass transition of 60 u corresponding to the loss of a molecule of acetic acid. Ion fingerprints from the glycosidic cleavage provided information on the mass of the aglycone (core), and the sequence and type of monosaccharides that constitute the sugar moiety. The tandem mass spectra of the saponin precursor ions [M + Na]⁺ provided a wealth of detailed structural information on the glycosidic bond cleavages. As a result, and in conjunction with existing literature, we characterized the structure of five new acetylated saponins, Lessoniosides A–E, along with two non-acetylated saponins Lessoniosides F and G at m/z 1477.7, which are promising candidates for future drug development. The presented strategy allows a rapid, reliable and complete analysis of native saponins.     

酸碱条件对枯草芽胞杆菌FJAT-14254代谢物产生的影响

为考察酸碱条件对枯草芽胞杆菌FJAT-14254代谢物产生的影响,采用气相色谱-质谱联用分析枯草芽胞杆菌FJAT-14254菌株的胞内成分。结果表明：通过谱库扫描得到32种高匹配率代谢物的初步鉴定结果,主要包括氨基酸类、酸类、烷烃类等,其中含量相对较高的有7种;枯草芽胞杆菌FJAT-14254代谢物的种类和含量与其培养环境的酸碱度变化呈一定的相关性,强酸性(pH＝3)条件下培养的胞内代谢物具有特异性,而接近中性(pH＝5、7)条件及碱性(pH＝9、11)条件下培养胞内代谢物则相似。由此推断,不同pH条件影     

氮磷钾肥对稻米铁、锌、铜、锰、镁、钙含量和产量的影响

 采用田间试验，在四川省西昌市用两个水稻品种研究了氮、磷、钾肥施用量对稻米中铁、锌、铜、锰、镁、钙含量和产量的影响。结果表明，稻米中铁、锌、铜、锰、镁、钙含量均随着施氮量增加先上升后下降，滇屯502的铁、锌、铜、锰、镁、钙含量和产量都以施用90 kg/hm2 N最高，稻谷产量以施用180 kg/hm2 N最高；而合系39的铁、锌、铜、锰、镁、钙的含量以施用180 kg/hm2 N最高，稻谷产量以施用270 kg/hm2 N最高，说明供试籼型品种滇屯502对氮肥的敏感性较粳型品种合系39强；磷肥明显降低了稻米中铁、铜、锰、钙的含量和产量，适量增施磷肥有利于增加稻米中镁的含量和产量；适量施用钾肥有利于提高稻米中铁、锌、铜、锰含量和产量，两供试品种铁、锌、铜、锰含量均以90 kg/hm2 K2O时最高，而钾肥明显降低了稻米中镁、钙的含量和产量。