热处理对采后青椒品质的影响

以“湘研NO．3”青椒为试材,采用48℃、60℃的热空气分别对青椒进行30min处理,置常温18～20℃条件下贮藏24天,探讨热处理对青椒采后品质的影响。试验结果表明,48℃热空气处理对降低青椒病害率,抑制青椒的软化和失重率的升高,延缓可溶性固形物、总酸含量、VC含量的下降效果较好;60℃处理可阻止叶绿素含量的下降,有效地抑制青椒果实呼吸强度上升。     

Application of citric acid and mild heat shock to minimally processed sliced radish: Color evaluation

The aim of this research was to study the effects of two hurdle technologies, citric acid application (CA) at 0.3%, 0.6% and 0.9% and thermal treatments (IT) for 1, 2 and 3 min at 50 °C, on the color of radish slices over 10 d of refrigerated storage. Contribution of the hurdles and their interactions were evaluated by examining the treatment effects on the following parameters: chromatic coordinates (L*, a* and b*) and the indices: chroma (ΔC*), total color difference (ΔE) and Color Index (CI*).The chromatic parameters for fresh radish (control samples) were L₀ = 69.43 ± 0.62, a₀ = −0.46 ± 0.05 and b₀ = 5.37 ± 0.37, while the calculated color indices were chroma = 5.39 ± 0.36, ΔE = 0 and CI* = −1.19 ± 0.17. Regarding control samples, the b* values showed an increasing trend during storage, which was associated with browning of the slices. Both ΔE and ΔC* values presented similar trends as reported for b*. Based on statistical analysis of the parameters and indices tested, the single hurdle application of low citric acid concentration (0.3%) or intermediate immersion time (2 min) at 50 °C minimized the radish slices color changes during storage. However, better results were obtained when two hurdles in series were applied. According to analysis, the treatment T7 (1 min IT, 0.3% CA) was selected as the best treatment to improve the retention of typical natural color of the minimally processed sliced radishes.     

大叶芹种子催芽技术的研究

以大叶芹（Spuriopimpinella brachyara）种子为材料,通过采用化学药剂、植物生长调节剂、层积处理及综合试验处理,寻找打破大叶芹种子休眠的方法。研究结果表明：低温层积处理和越冬层积具有破除大叶芹种子休眠的作用,低温层积(4±1)℃的条件较其他层积条件下种子发芽率高,是最佳的层积处理方法。采用不同浓度的赤霉素（GA3）、生长素（IAA）、6-苄基腺嘌呤（6-BA）预处理后结合低温层积处理,结果表明：250 mg/L GA3浸种24 h后低温层积100天可使种子发芽率达60%左右,发芽势较高,且腐烂率低,基本上解除了大叶芹种子休眠现象。     

不同施肥量对高原夏季青花菜产量、品质及养分吸收的影响

探索不同施肥量处理对高原夏菜的影响效应,以青花菜为试验材料,在大田条件下研究不同施肥量处理对青花菜产量、品质及养分吸收的影响,为甘肃省河西地区高原夏季青花菜制定合理施肥方案与优质高效生产提供理论依据。结果表明：氮肥是影响产量的关键因素,高氮处理的产量、花球紧实度和花球叶绿素含量比低氮处理高;而高氮和较高的氮、磷比例以及钾肥不足可导致青花菜硝酸盐含量增加、可溶性糖含量下降;施肥量过高或过低,都会使Vc含量降低。青花菜植株对氮、磷、钾的吸收以钾最多,氮次之,磷最少。相关性分析表明,青花菜植株内氮、钾含量与产量和花球叶绿素含量极显著正相关,磷含量与可溶性糖、Vc含量极显著正相关,说明充足的氮、磷、钾营养对青花菜产量与品质的提高具有重要意义。合理的氮磷钾配施可调控青花菜主要矿质养分的吸收与分配,促进叶片与花球中养分的积累,从而提高花球的产量与品质。     

鸡粪与化肥不同配施方式对土壤有机碳及杨树幼苗生长的影响

通过盆栽试验,研究了N100(尿素提供100%的氮),M10N90(鸡粪和尿素分别提供10%和90%的氮),M30N70(鸡粪和尿素分别提供30%和70%的氮)和M50N50(鸡粪和尿素各提供50%的氮)等不同施肥处理下,土壤有机碳含量、活性有机碳含量和碳库管理指数(CPMI)的变化规律。结果表明,M30N70和M50N50处理的有机碳含量分别比N100处理提高了8.11%和14.64%;M30N70处理的活性有机碳含量和CPMI均为最高,其中活性有机碳含量分别比N100,M10N90和M50N50处理提高了47.36%,14.93%和7.14%,CPMI分别提高了65.49,26.74和20.22,其差异均达到显著水平;同时,M30N70处理对杨树幼苗地径和苗高生长的提高幅度最大。土壤活性有机碳与总有机碳、杨树苗的地径和苗高呈显著相关,与CPMI呈极显著相关;CPMI与地径、苗高呈显著相关,能够指示土壤生产力的变化。由此可见,鸡粪与化肥的不同配比对土壤有机碳、活性有机碳、CPMI及杨树幼苗的生长均有显著影响,其中鸡粪与化肥以3∶7比例配施的作用效果最佳。     

干旱处理对土壤水分变化及大豆产量的影响

采用框栽方式,研究不同阶段干旱处理对土壤水分、大豆植株干物质积累及产量的影响。结果表明,土壤含水率随干旱历时的增加而递减,长时间干旱后稳定在20%～24%;对于短期干旱处理,灌溉量较大时,土壤含水率会迅速恢复到稳定值32%～34%,但是对于18d以上的干旱历时,较少的灌溉量并不能保证土壤含水率在1～2次灌溉后得到恢复,表明较少的灌溉量对土壤含水率的提升能力有限。各干旱处理结束时期,大豆植株干物质积累均随干旱历时增加呈下降趋势,长期干旱会使全株干物质积累下降13%～30%;苗期和花荚期的短期干旱处理产生激发补偿效应,不会使大豆减产,结荚鼓粒期对水分供应较为敏感,干旱导致大豆减产。     

Hypericum perforatum L. Seed Germination: Interpopulation Variationand Effect of Light, Temperature, Presowing Treatments and Seed Desiccation

Germplasm conservation of medicinal plants is of increasing interest and, when possible, seed banking is the most efficient system for ex situ conservation of these plant genetic resources. Hypericum perforatum L. (St. John's wort, Guttiferae) is a medicinal plant with evidence of efficacy as an anti-depressant. The aim of this work was to increase knowledge of its seed germination behaviour by studying 68 wild populations. Seed germination tests were carried out at 25/15 °C under a photoperiod of 16-h light/8-h darkness. Final germination percentages were highly variable depending on the accession, ranging from 6 to 98%. Similarly, germination rate (as expressed by T ₅₀ values) varied significantly from 6.1 to 23.0 days. The effect of seed desiccation with silica gel on subsequent germination was also studied. The effect of two other incubation temperatures (15 and 25 °C) and light (photoperiod or darkness) on seed germination was studied in several accessions. Temperature had no significant effect on final germination percentages. However, light significantly increased the germination of most but not all accessions assayed. Seeds from four accessions with low germination percentages were subjected to different presowing treatments that could increase germination: dry heat, hot water and gibberellic acid. Germination was promoted significantly by gibberellic acid in two of the four accessions assayed, but the thermal treatments did not enhance significantly the germination percentages. This study reveals that conclusions based on one population of Hypericum perforatum cannot characterize the germination behaviour for the entire species.     

山茶花灰斑病发生规律及防治研究

重庆地区山茶花灰斑病Pestalotio psis gue piniDesm.发生在5-10月，一年中有2个高峰期，并和气温，降雨密切相关，第一个高峰期在梅雨季节和抽新梢期的5-6月初；第二个高峰期为7月初至8月中旬的高温季节。10月下旬，病原菌以分生孢子或分生孢盘在病叶上越冬，翌年4月底5月初侵染山茶花嫩叶，发病初期，混合或单喷70%甲基托布津 杀毒矾M8或58%甲霜灵或杀毒矾M8800倍液3-5次，其防效分别为100%、92.3%和90.33%。     

天然群落枯枝落叶浸提液与其它处理对伯乐树种子发芽的比较研究

用天然群落枯枝落叶浸提液浸种与其它处理方法进行伯乐树种子发芽试验,试验分室内和大田萌发试验,室内又进行了不同浸提液、不同激素处理、不同温度处理对伯乐树种子发芽的影响.结果表明:(1)蒸馏水浸种发芽率＞伯乐树群落枯枝落叶浸提液浸种发芽率＞罗浮栲群落枯枝落叶浸提液浸种发芽率,但差异不大;其中蒸馏水处理的种子发芽率最高(69.2％).(2)以200mg· L-1 GA3浸种12 h发芽率最高,达到80.0％.GA3浸种的伯乐树种子发芽率＞蒸馏水浸种的发芽＞ IAA浸种的发芽率.(3)大田试验的发芽率与室内试验发芽率基本接近;其中酒精浸提液处理的种子发芽率较高,达70.4％.(4)伯乐树发芽最适宜温度是20～25℃.发芽开始后第10～26天为发芽高峰期;发芽可持续32天.(5)在20℃条件下第7-14天腐烂率较高;随着温度的升高,高腐烂率出现的时间推迟,但发芽率相对降低.