氮、钾、硅肥对水稻苗生长和抗瘟性的影响

通过温室稻瘟病菌人工接种法,研究了氮、钾、硅肥5个不同用量对3个不同抗瘟水平的水稻品种幼苗生长及病情指数的影响。结果表明,与未施肥的对照相比,增施氮、钾肥能明显促进水稻的生长,增加叶长和叶宽。氮肥用量与水稻品种特优627(R)、D奇宝优527(MR)和汕优63(MS)苗瘟病指有显著的正相关关系,钾肥和硅肥用量与品种汕优63苗瘟病指有显著的负相关关系,3个水稻品种的叶宽与苗瘟病指有极显著的正相关关系。增施氮肥有利于苗瘟的发生,而增施钾肥和硅肥能提高中感品种的抗瘟性。     

不同土壤水分条件下硅对坪用高羊茅种子出苗及生物学特性的影响

水肥耦合不仅可以维持草坪草的正常生长,而且可以减少一定的灌溉量。采用盆栽试验研究了不同土壤条件下硅对坪用高羊茅种子出苗及生长的影响。结果表明,不添加硅时,高羊茅种子适宜出苗时的土壤含水量应为饱和含水量的４５％～６０％,植株生长适宜的土壤含水量应为饱和含水量的７５％以上;当土壤含水量大于或等于饱和含水量的６０％时,添加硅不仅能够提前坪用高羊茅种子的初始出苗时间,缩短集中出苗时期,提高出苗率,而且能够显著促进高羊茅的株高和叶长生长,增加地上和地下生物量（P＜０．０５）,而当土壤含水量小于或者等于饱和含水量的４５％时,添加硅对高羊茅种子出苗和生长发育没有明显影响,说明添加硅对坪用高羊茅生长的有益作用受土壤含水量的约束;土壤含水量为饱和含水量的６０％时,添加硅处理中植株的分蘖数、株高、叶长和生物量与对照处理中土壤含水量为饱和含水量的７５％时植株的分蘖数、株高、叶长和生物量差异不显著,说明添加硅能降低高羊茅植株正常生长所需的土壤含水量,有利于节约灌溉量。     

Alleviation of Chromium Toxicity by Silicon Addition in Rice Plants

The alleviatory effect of silicon (Si) on chromium (Cr) toxicity to rice plants was investigated using a hydroponic experiment with two Cr levels (0 and 100 μmol L-1),three Si levels (0,1.25,and 2.5 mmol L-1) and two rice genotypes,differing in grain Cr accumulation (Dan K5,high accumulation and Xiushui 113,low accumulation).The results showed that 100 μmol L-1 Cr treatment caused a marked reduction of seedling height,dry biomass,soluble protein content,and root antioxidant enzyme activity,whereas significantly increased Cr concentration and TBARS (thiobarbituric acid reactive substances)content.However,the reductions of seedling height,dry biomass,and soluble content were greatly alleviated due to Si addition to the culture solution.Compared with the plants treated with Cr alone,Si addition markedly reduced Cr uptake and translocation in rice plants.No significant differences were observed between the two Si treatments (1.25 and 2.5 mmol L-1) in shoot Cr concentration and Cr translocation factor.Under the treatment of 100 μmol L-1 Cr+2.5 mmol L-1 Si,higher root Cr concentration but lower shoot Cr concentration and Cr translocation factor were observed in Dan K5 than those in Xiushui 113,indicating that the beneficial effect of Si on inhibiting Cr translocation was more pronounced in Dan K5 than in Xiushui 113.Si addition also alleviated the reduction of antioxidative enzymes (superoxide dismutase (SOD) and ascorbate peroxidase (APX) in leaves; catalase (CAT) and APX in roots) and the increase of TBARS content in the Crstressed plants.Furthermore,the beneficial effects of Si on activities of antioxidative enzymes under Cr stress were genotype-dependent.The highest activities of SOD,POD (guaiacol peroxidase),CAT,and APX in leaves occurred in the treatment of 100 μmol L-1 Cr+2.5 mmol L-1 Si for Xiushui 113 and in the treatment of 100 μmol L-1 Cr+1.25 mmol L-1 Si for Dan K5.The beneficial effect of Si on alleviating oxidative stress was much more pronounced in Dan K5 than in Xiushui 113.It may be concluded that Si alleviates Cr toxicity mainly through inhibiting the uptake and translocation of Cr and enhancing the capacity of defense against oxidative stress induced by Cr toxicity.     

硅肥对花生生理特性和产量的影响

金龟牌二代硅肥用于花生试验结果表明,施用硅肥后提高了花生叶片的叶绿素含量和光合作用,增加了茎叶及荚果干物质积累量,从而使花生植株生长健壮,叶色深绿,分枝多,果仁充实饱满、空壳少、百果重和百仁重提高,出仁率高,增产显著,增产幅度达20%。     

中小型养猪场风机调速系统

为了适应中小型养猪场环境控制的需要,该文介绍了一种新型的单相风机调速控制系统。该系统使用单片机来控制单相交流通风机,通过改变风机的供给功率,达到调速、控制通风的目的,且结构简单,成本低廉,实际应用效率较高。     

硅对不同pH水田土壤镉吸附热力学特征的影响

以硅酸钠为硅源,在中和其碱性和消除钠离子影响的基础上,进行不同温度条件下的吸附等温试验,探讨了加硅对土壤镉吸附热力学特征的影响。结果表明:不同硅水平下,Freundlich方程均可较好地描述三种温度下(25、35、45℃)两种土壤镉的吸附特征;在不同的温度下,加硅均降低了碱性土壤镉的吸附容量、增大了其吸附强度,增加了酸性土壤镉的吸附容量、降低了其吸附强度;两种土壤吸附镉的热力学参数均为ΔG0、ΔH0、ΔS0,说明土壤对镉的吸附均是吸热、熵增的自发过程;加硅后,碱性土壤对镉吸附过程的ΔG变大、ΔH变小、ΔS变小,酸性土壤对镉吸附过程的ΔG变小、ΔH变大、ΔS变大,说明与对照相比,加硅使碱性土壤吸附镉的自发性降低,使酸性土壤吸附镉的自发性提高。     

硅对Cd、Pb、Cu、Zn正交胁迫下水稻丙二醛含量的影响

采用土壤重金属正交L9(34)胁迫方法 ,通过盆栽试验,研究喷施有机硅和无机硅溶液对水稻叶片丙二醛(MDA)含量和变化趋势的影响。结果表明,土壤受重金属污染,水稻叶片MDA含量显著升高,随着重金属胁迫浓度升高,MDA含量逐渐增加;随着生长时期的延长,MDA含量呈现先升高后下降的趋势。不同种类重金属对水稻叶片MDA含量影响由大到小依次是Cd、Pb、Cu、Zn。经有机硅处理的水稻叶片MDA含量(504.63μmol/g FW)最低,无机硅处理(565.85μmol/g FW)次之,无硅处理(611.73μmol/g FW)最高,不同处理间叶片MDA含量差异水平极显著(P0.01)。可见,硅处理有利于维持水稻膜脂过氧化系统平衡,诱导其抵御重金属胁迫的毒害机制。     

镉胁迫下硅对高粱生长的影响及其作用机制

尽管硅提高植物的抗镉毒害已经被广泛的报道,但是其作用机理还不明确。该试验研究在镉胁迫的条件下,硅对高粱生长的影响及作用机制。结果发现:外源施加硅能显著地缓解镉对高粱无论地上部分还是地下部分鲜重及干重的抑制作用。抗氧化酶结果表明:在正常条件下,硅对抗氧化酶的活性没有显著的影响。在镉毒害的条件下,硅显著增强CAT和POD的活性,SOD的活性不受影响。与此相对应:硅显著地降低MDA的含量。对有机酸的分析发现:在镉胁迫的条件下,叶片中有3种有机酸能够检测到:草酸,丙二酸,丁二酸,并且其含量都在硅的调节下增加。而在根系中所检测的4种有机酸中,草酸和丙二酸的含量受到硅的调节而增加,柠檬酸的含量不受影响,而苹果酸的含量却有下降的趋势。上述结果表明:硅增强高粱幼苗的抗镉胁迫与其增强高粱抗氧化酶活性及增加高粱体内有机酸的含量相关。