磁化处理对楸树嫩枝扦插生根及生长的影响

以楸树无性系3年生母树的当年生半木质化枝条为试验材料,采用完全随机试验设计,研究磁化水喷淋+磁化毯(MW+MR)、磁化毯(MR)、磁化水喷淋(MW)和非磁化水喷淋(CK)4个处理对楸树扦插生根的作用。通过对不同处理扦插苗生物量积累及生根率进行对比,揭示磁化处理对楸树嫩枝扦插生根的影响。结果表明:1)MW+MR处理有利于促进插穗生根,插穗生根率和根系效果指数均显著高于MR、MW处理及CK(P<0.05);MW+MR、MR及MW处理的新梢基径、新梢平均长度、叶片数量及叶片面积均高于CK,差异性极显著(P<0.01)。2)磁化处理对扦插苗根系形态有显著影响,其中MW+MR、MR和MW处理的根系长度、直径、表面积和体积显著高于CK(P<0.05)。因此,磁化处理有利于提高楸树嫩枝扦插生根率,促进根系生长和生物量的积累。

Photosynthetic Characteristics of Clerodendrum trichotomum Thumb. Responses to Drought, Salt and Water-logging Stresses

In order to reveal the photosynthetic characteristics of C. trichotomum responses to drought, salt and water-logging stresses, one-year-old potted seedlings were taken as materials, and the several stresses including natural drought, submergence stress, water-logging and different salt treatments （0.2%, 0.4%, 0.6% and 0.8% NaCl） were carried out on August 15, 2012. The morphological and photosynthetic characteristics were observed and determined. The results showed that adverse enviromental stress had a significant effect on the morphological changes and photosynthetic characteristics of C. trichotomum. On the 14th day after natural drought, the leaves wilted and could not recovery at night, and 60% of the seedlings could recover after re-watering. From the 7th day to the 10th day after submergence stress treatment, the 2nd and the 3rd leaves at the base of 60% seedling turned yellow and the lenticels were observed. At the early stage of water-logging stress, white lenticels appeared at the base of seedlings, and the leaves wilted, chlorina and fallen off on the 8th day. A large number of leaves fallen off under 0.6% NaCl or more salt stress, and even the whole plant died. The chlorophyll content, net photosynthetic rate （Pn） and transpiration rate （Tr） decreased gradually with the stress process, such as 8 days after natural drought, less than 0.4% salt stress and water-logging stress, but the changes were not significant compared with those of the control. With the increase of the stress intensity and the prolonged time, the changes of photosynthetic index were significant. All the results indicated that C. trichotomum had a certain degree of tolerance to drought, water and salt, but it was not suitable for living, in water-logging condition for a long time.

水果风味物质的生物制备技术

风味物质是人类通过味觉或嗅觉产生的电信号在人大脑皮层产生不同感知,从而对食品产生不同感觉的一类物质,包括呈香物质和呈味物质。传统制备天然风味物质的工艺条件易受外界条件的限制,因此,在传统工艺的基础上,结合生物技术制备水果风味物质具有十分广阔的前景。本文主要综述了细胞培养、基因工程、微生物转化等生物技术制备水果风味物质的研究进展,并阐明了新型生物技术在天然风味物质制备上的发展前景。

鲁中南山区松树人工林近自然经营效果分析

近自然抚育作业于徂徕山林场、泰山林场和明光寺林场进行,采用目标树抚育作业方式,对不同林分进行间伐处理,时长分别为2、10和3年。结果表明,与对照相比,抚育处理后林分平均胸径、树高和冠幅较对照提高3.13%~12.89%、3.03%~8.91%和2.75%~25.91%;林分生长速度加快,保留木的胸径、树高和冠幅年生长量分别提高21.43%~66.67%、9.21%~26.15%和64.29%~300%;林下灌木层植物种类增多,出现侧柏、臭椿等喜光物种;油松纯林和松栎混交林中草本植物多样性改善,Simpson、Shannon-wiener和Gleason指数分别提高0.95%~1.93%、5.33%~10.43%和4.67%~18.18%,马唐、大油芒、羊胡子草等植物重要值提高;另外,抚育间伐后林下土壤pH提高0.77%~3.78%,土壤容重降低5.48%~12.68%;同时,过氧化氢酶、土壤磷酸酶、土壤蔗糖酶、土壤脲酶活性较对照分别提高6.74%~29.33%、4.79%~4.99%、2.13%~10.34%和1.25%~25.56%。近自然抚育间伐在一定程度上可以促进林分生长量积累、丰富林下植物多样性、改善林下土壤质量。

盐胁迫对西南卫矛生长及光合特性的影响

以西南卫矛(Euonymus hamiltonianus Wall. ex Roxb.)为试材,设置4个NaCl质量浓度(0、2.0、4.0、6.0 g·L^-1)处理,通过对其叶片光合气体交换参数(净光合速率、蒸腾速率、气孔导度和细胞间CO2浓度)、生物量、相对电导率、叶绿素含量及叶绿素荧光动力学特征的测定,分析了盐胁迫对西南卫矛生长与光合特性的影响。结果表明:与对照相比,2.0、4.0、6.0 g·L^-1盐浓度处理下西南卫矛净光合速率、蒸腾速率、气孔导度、气孔限制值和水分利用效率显著降低,胞间二氧化碳浓度显著升高,叶片最大光化学效率和单位面积有活性的反应中心数目均显著降低,OJIL曲线中K点和J点均大幅上升,叶绿素含量显著降低;2.0 g·L^-1盐浓度处理下西南卫矛根冠比和相对电导率与对照差异均不显著,而4.0、6.0 g·L^-1盐浓度处理下西南卫矛根冠比和相对电导率显著升高。表明西南卫矛对低浓度盐胁迫有一定的耐受能力,但高浓度盐胁迫会对西南卫矛造成影响,抑制PSⅡ活性,降低光化学效率,降低植株对营养物质的吸收和利用,使植株的生长受到阻碍甚至死亡。