低温处理对紫苏生理指标的影响

[目的]研究低温处理对紫苏生理指标的影响,确定造成紫苏叶片低温伤害的时间。[方法]将紫苏叶分别低温处理0、12、24、36、48和60 h,并测定其叶绿素、可溶性蛋白质及可溶性糖的含量,并考察2～5℃低温对紫苏叶片生理指标的影响,确定紫苏叶片低温伤害的时间。[结果]低温处理48 h能明显减少叶片中叶绿素的含量,而且低温处理60 h的叶绿素含量减少非常明显;低温处理48 h能明显减少叶片中可溶性蛋白质和可溶性糖的含量。[结论]低温处理超过48 h,紫苏就会受到伤害;低温处理时间达到60 h时,紫苏受到的伤害程度加重。     

Accumulation and Mobility of Salts in Soil as Influenced by Primary Biomethanated Spentwash

A soil column laboratory experiment was carried out at the central campus, Mahatma Phule Agricultural University, Rahuri, India during 2008–2009 to study the accumulation and mobility of salts in Typic Haplusterts as influenced by primary biomethanated spentwash (PBSW). The PBSW was applied in three different levels (0.5, 1.0, and 2.5 cm) and then tap water with low salinity and low sodium hazard (C₁S₁ class) was used to carry out leaching in four different levels of water at the pore volume of soil (WPVS) (0.5, 1.0, 1.5, and 2.0). The electrical conductivity (EC) in the soil increased significantly with increasing levels of PBSW and decreased with increasing levels of WPVS in surface (0–15 cm deep) and subsurface (15–30 cm deep) soil layers. The exchangeable calcium (Ca²⁺), magnesium (Mg²⁺), and potassium (K⁺) increased, whereas exchangeable sodium (Na⁺) decreased with increasing levels of PBSW and WPVS in surface and subsurface layers of soil. The organic carbon content increased with increasing levels of PBSW and decreased with increasing levels of WPVS in both the soil layers. The cation exchange capacity (CEC) increased with increasing levels of PBSW and WPVS in both the soil layers. The exchangeable sodium percentage (ESP) decreased with increasing levels of PBSW and WPVS over the initial values of soil in both the layers. The pH of saturated paste (pHs) was reduced and electrical conductivity of extract (ECe) was increased with increasing levels of PBSW and WPVS in both the layers. The Na⁺ content of saturation paste extract increased significantly with increasing levels of PBSW and WPVS in both the soil layers.     

Suppressive effect of liquid potassium silicate on powdery mildew of strawberry in soil

A soil drench of soluble silicon (liquid potassium silicate) was tested for the control of powdery mildew of strawberry in soil for 2 years in a vinyl house under growers' conditions on two cultivars: very susceptible Toyonoka and slightly susceptible Sachinoka. Soluble silicon suppressed the disease more effectively as a preventive control than as a control to reduce initial incidence. The suppressive effect against this disease was more effective for Toyonoka than for Sachinoka. The control value of soluble potassium silicate was 85.6% for Toyonoka in the first year and 60.2% in the second year, while for Sachinoka it was 58% in the first year and 40.6% in the second year. Strawberry leaf hardness was measured for the control and silicate-treated leaves. Although silicate-treated leaves seemed to be harder than control leaves, leaf hardness did not vary significantly between controls and silicate-treated leaves in either of the 2 years, and the mode of preventive action of liquid potassium silicate remains unknown. A factor other than a physical action may be involved.     

甜瓜可溶性固形物含量的遗传表现与基因效应分析

通过半轮配双列杂交,分析了甜瓜可溶性固形物含量的遗传特性。研究结果表明,遗传方差组成中,基因的加性效应和显性效应都是显著的,但加性效应占相对主要优势,狭义遗传力(h2N)值为65%。基因的分布是不均衡的,控制该性状的基因W为显性基因,但表现为不完全显性,可溶性固形物含量选择的较好世代在F4代。     

梨果实贮藏中可溶性果胶和半纤维素分子结构的变化

 为了了解分子结构变化与耐藏性的关系，以耐贮性不同的苹果梨和新高梨为试材，利用Ultrogel AcA 22凝胶柱渗漏分离，比较了梨贮藏中可溶性果胶和半纤维素分子大小的变化。结果表明，苹果梨的半纤维素分子大于新高梨。在贮藏过程中，耐贮性强的苹果梨果实可溶性果胶分子大小变化不明显，但半纤维素分子明显变小。相反，新高梨的可溶性果胶分子明显变小，而未观察到半纤维素分子大小的变化。说明梨的耐贮性与可溶性果胶分子结构变化及半纤维素分子大小有关，而与半纤维素分子结构变化没有直接关系。     

月季花瓣衰老过程中可溶性蛋白的SDS—PAGE分析

对月季花瓣衰老过程中可溶性蛋白的ＳＤＳ－ＰＡＧＥ进行了分析，结果表明，蛋白条带变化表现出３种情况：（１）从瓶插开始到结束蛋白条带基本保持稳定；（２）随花瓣衰老，蛋白条带逐渐减弱、消失；（３）随着花的衰老，有新的蛋白条带出现。对花进行ＡＢＡ或乙烯促衰处理，也导致相应的某些蛋白条带的变化，说明这些蛋白的变化可能与衰老有关。     

菘蓝根腐病菌毒素最适浓度的筛选及其对菘蓝幼苗可溶性蛋白的影响

［目的］为深入研究菘蓝对根腐病的抗性机制提供理论依据。［方法］采用不同浓度菘蓝根腐病菌毒素处理菘蓝幼苗，筛选最适处理浓度；对最适浓度毒素处理过的菘蓝幼苗的外部形态进行鉴定，并测定其可溶性蛋白的含量。［结果］稀释10、20倍毒素处理过的菘蓝幼苗在试验期间全部萎蔫死亡，稀释40、50倍毒素处理过的菘蓝幼苗在试验期间大部分无病变现象，稀释30倍毒素处理过的菘蓝幼苗病变现象明显，处理72 h后50%幼苗萎蔫死亡。经稀释30倍毒素处理的菘蓝幼苗可溶性蛋白的谱带大体相同，但也出现了个别特异性条带；经毒素处理的样品蛋白条带数多于对照，且染色较深。［结论］菘蓝根腐病菌毒素的筛选压力以稀释30倍最好。     

圆叶决明添加量对红壤可溶性氮及酶活性的影响

为了探明圆叶决明(Chamaecrista rotundifolia)降解后红壤可溶性氮及氮水解酶活性的变化规律,本研究采用室内好气恒湿培养法,研究占红壤质量0.5%(T1),1%(T2)和2%(T3)的圆叶决明添加至红壤中,培养7~88d内红壤硝态氮(NO^-₃-N)、铵态氮(NH⁺₄-N)和可溶性有机氮(Soluble organic nitrogen,SON)及脲酶、蛋白酶和天冬酰胺酶的变化。结果表明：添加圆叶决明后,红壤NO^-₃-N和NH⁺₄-N含量在培养前期降低,培养中期增加;而整个培养期SON含量及脲酶、蛋白酶和天冬酰胺酶活性均增加,且圆叶决明添加量越大,效果越显著。NO^-₃-N和SON含量及脲酶、蛋白酶和天冬酰胺酶活性可用2次或3次函数方程拟合;而NH⁺₄-N含量可用线性函数拟合。氮水解酶与NO^-₃-N负相关,与NH⁺₄-N和SON正相关,且相关性从大到小的顺序为蛋白酶>天冬酰胺酶>脲酶。综上,添加圆叶决明提高了红壤供氮水平和红壤氮转化能力。     

Effects of coppicing on the root and stump carbohydrate dynamics in birches

Whole birch stems were cut off in order to determine how coppicing affects root and stump starch, glucose, fructose and sucrose concentrations and their correlation with shoot regeneration capacity. The Betula pubescens Ehrh. and B. pendula Roth studied included intact trees, trees that had been coppiced 8 years earlier, trees coppiced at the beginning of the experimental season, and birches that had been coppiced twice, 8 years earlier and at the beginning of the experimental season. Carbohydrate accumulation differed between 8 years earlier coppiced and intact trees. Recent coppicing clearly decreased the starch and sugar concentrations of the roots, which were often highest in the thin roots. The concentrations of these compounds in the stumps were always low, although the carbohydrate concentrations of stumps, in particular, correlated with shoot regeneration capacity. Starch was the most labile of the carbohydrates measured and most clearly reacted to coppicing. Differences in starch- and sugar-reserve dynamics indicate a difference between these birch species in the use and replenishing of root and stump reserves. This information may also be of help when the effects of other stresses, for example, severe animal damage or burning, on the regrowth of young birch stands are estimated.     

低温下7个草莓品种的抗性生理指标比较

以7个草莓新品种为试材,在-15～4℃范围内设置7个温度梯度处理,测定草莓叶片叶绿素、可溶性糖、游离脯氨酸及丙二醛(MDA)含量,以评价其抗寒性。结果表明,低温处理后,宁玉叶片中叶绿素含量最高;隋珠、宁玉的可溶性糖含量较高,但各品种间差异不明显。脯氨酸含量受到影响因素较多,不能从含量上判断与抗寒力强弱的相关性;京藏香的MDA含量一直较高,宁玉的MDA含量较低且稳定。宁玉的抗寒力最强,京藏香较弱,其他品种介于两者之间。