蔗叶覆盖还田系列研究I.对甘蔗工、农艺性状的影响

为探索蔗叶还田对甘蔗工艺现状及农艺性状的影响,以火烧蔗叶后不做任何覆盖为空白对照(CK_1),以火烧蔗叶后覆盖地膜为常规对照(CK_2),对单独的蔗叶覆盖和蔗叶+地膜覆盖进行了连续两年的试验研究。结果表明:蔗叶+地膜覆盖可提高出汁率,但对重力纯度、纤维分、甘蔗含糖分、甘蔗还原糖没有促进作用;蔗叶覆盖增加宿根甘蔗发株数,提高发株率,有效茎数增加,株高增高,茎径增大,单茎重增重,甘蔗产量极显著提高,值得在生产上应用推广。     

蔗叶不同还田模式对土壤水分和甘蔗产量的影响

田间试验研究了蔗叶不同还田模式对旱地蔗园土壤水分和甘蔗产量的影响。结果表明,蔗叶不同还田模式的甘蔗产量差异不显著,蔗叶全覆盖还田与蔗叶隔行覆盖还田处理的总苗数较焚烧处理差异达极显著性水平(P0.01),有效茎与焚烧处理差异达显著性水平(P0.05)。蔗叶全覆盖还田与蔗叶隔行覆盖还田对宿根蔗垄上前期与后期的土壤水分保持效果较好,不同蔗叶还田模式对甘蔗行间的土壤水分保持效果较好。     

蔗叶粉碎还田对甘蔗螟虫发生的影响

根据生产上甘蔗收获期蔗叶处理方法的不同,通过田间试验,测定了蔗叶焚烧和蔗叶粉碎还田对当年宿根蔗的甘蔗螟虫发生的影响.结果表明:在苗期,甘蔗螟虫以二点螟为主;在甘蔗生长中后期,条螟、黄螟和二点螟混合发生为害,但条螟种群数量最大.与蔗叶焚烧处理相比,蔗叶粉碎还田处理中,螟害导致的螟害株率相当,分别为94.17％和91.39％,但枯心率和螟害节率均显著降低,分别为43.86％、12.29％和17.23％、13.57％,表明蔗叶粉碎还田有利于减轻甘蔗螟虫为害.     

甘蔗叶不同还田方式对土壤养分的影响

为减轻秸秆焚烧所带来的环境问题和充分利用甘蔗叶资源,在大田环境下动态监测甘蔗叶粉碎、焚烧和深埋3种还田方式对土壤养分的影响。结果表明:甘蔗叶粉碎还田和深埋还田有利于甘蔗叶中有机碳及氮、磷、钾养分的缓慢释放;甘蔗叶焚烧还田提高了土壤碱解氮含量5.6~20.9 mg/kg和速效磷含量0.8~4.0 mg/kg,促进土壤中氮磷向有效态转化,焚烧还田初期显著增加了土壤速效钾的含量12.3~18.3 mg/kg,但焚烧会损失部分甘蔗叶中碳氮元素,也造成环境污染。综合分析认为甘蔗叶粉碎还田是比较省工、方便的处理方式。     

蔗地实施"机耕粉碎蔗叶还田"试验示范总结

蔗地实施"机耕粉碎蔗叶还田"能产生一定的经济效益,能增加土壤有机质含量,改善土壤理化性状,提高甘蔗抗旱能力.     

蔗叶还田方法对宿根蔗地一些土壤肥力因素的效应研究

本试验在大田生产条件下,研究新植蔗地蔗叶还田对宿根蔗地一些土壤肥力因素的效应。试验结果表明：蔗叶还田能提高宿根蔗地的土壤pH值及土壤速效N、土壤速效P和土壤速效K含量,起到培肥地力,促进甘蔗生长的作用。其中尤以C处理对蔗地的培肥效果最好。     

蔗种茎径对甘蔗农艺性状的影响

为了充分发挥甘蔗良种性能,进行了A大茎(平均茎径3.29 cm、种段重96.4 g)、B中茎(对照;平均茎径2.33 cm、种段重44.8 g)和C小茎(平均茎径1.83 cm、种段重19.4 g)甘蔗种茎对其生长特性及产量影响的试验研究.结果表明,A处理的萌芽率为44.4％,分别显著低于B、C处理的59.7％和58....     

蔗叶还田与焚烧对改良土壤效果试验

改良土壤是提高广西甘蔗产量的重要措施之一。本文以台糖22号第一年、第二年宿根为材料，采用蔗叶还田，焚烧蔗叶的方法，通过田问试验对比，调查出苗数、分蘖率、保水保肥力、有机质及速效N、P、K转化情况等。结果表明：蔗叶还田能有效的改良土壤，培肥地力，保持土壤中水分、养分，提高土壤有机质含量及速效N、P、K含量，是一种成本低廉且能提高甘蔗产量的有效途径，值得推广应用。     

菠萝-甘蔗轮作制度对甘蔗生长和土壤微生物区系的影响

2000—2002年进行菠萝一甘蔗轮作田间试验。结果表明：菠萝-甘蔗轮作甘蔗的产量和糖度都高于与甘蔗一甘蔗连作：轮作田与连作田比较能改善土壤的通气性，加速速效性养分的释放，增加土壤微生物总量(一般好气性细菌、真菌、放线菌)；有益的氨化细菌和硝化细菌成倍增加，而无益的厌氧性细菌、反硝化细菌则受到抑制；固氮菌数量变化不大。     

2种椰心叶甲寄主植物的叶片防御特性

近年来椰心叶甲[Brontispa longissima(Gestro)]对槟榔的危害逐渐加剧,而寄主植物对入侵害虫椰心叶甲的物理抗性研究鲜有报道.本研究对取自椰子、槟榔的5种叶片的叶绿素、蜡质、维管束、茸毛等物理特性进行研究,揭示椰心叶甲的物理抗性机制.结果表明:椰心叶甲对寄主叶片的取食选择性和产卵选择性之间存在显著...     

台湾牛樟在海南引种栽培及生长特性研究

为了在海南成功引种台湾牛樟,以获得适合当地种植、推广的优势树和栽培技术,对半年生台湾牛樟幼苗进行引种栽培试验。研究台湾牛樟幼苗在3种不同郁闭度(郁闭度0、0.3、0.8)和3种基质类型(酸性砖红壤,椰糠+红壤,河沙+红壤)下的成活情况、生长状况。结果表明:台湾牛樟一年3~4次抽稍,属中期生长型,嫩叶与新梢颜色呈棕红、浅绿相间,树体主干分叉生长。在郁闭度0.3条件下,幼苗成活率、保存率为最大值,分别是100%和93.3%;郁闭度0和0.3条件下,2年生台湾牛樟树高、地径、冠幅的总生长量较高,引种表现出良好的适应性和抗逆性;郁闭度0.8黄桐林下套种表现最差;3种基质类型中幼苗成活保存率以椰糠+红壤基质最高。说明郁闭度是影响台湾牛樟生长发育的主要因子,栽培基质具有促进其生长发育的作用。      

Influence of liming and form of nitrogen fertilizer on nutrient uptake,growth, yield,and quality of Virginia (flue-cured) tobacco

Soil acidity is a limiting factor affecting the growth and yield of many crops all over the world. It is recognized that liming is the most common management practice of profitable crop production on acid soils. On the other hand, it is well-known that the form of nitrogen may affect tobacco yield and quality. In this work, the impact of the interaction between three hydrated lime (HL, Ca(OH)₂) rates (0, 1.5 and 3 t HL ha⁻¹) and three nitrogen fertilizer forms (NO₃-N 100%, NH₄-N 100% and NO₃-N 50% plus NH₄-N 50%) on growth, yield and quality characteristics of Virginia (flue-cured) tobacco was investigated in a 4-year (1995–1998) field experiment established in an acid soil (pH_{water 1:1} 5.3) located in Northern Greece. Lime was applied only once in December 1994, while nitrogen fertilizer was applied annually before transplanting. The results showed that the effect of liming on tobacco growth was not dependent on time, weather conditions and form of nitrogen fertilizer. Liming increased soil pH, enhanced the early growth of tobacco (within 30 days after transplanting (DAT)) and finally increased the total gross and trade yield of tobacco proportionally to the amount of HL added. However, the quality index (organoleptic characteristics) of the cured product was improved only at the HL application rate of 3 t HL ha⁻¹. Furthermore, liming significantly increased Ca and P concentrations but decreased K concentration in cured tobacco leaves. Tobacco yield increase was attributed to the increase of P uptake. Liming also increased the ash content of cured leaves, whereas it did not significantly affect nicotine, total nitrogen and reducing sugars. The use of ammonium N in fertilizer delayed the early growth of tobacco, reduced the nicotine concentration and increased the reducing sugars concentration of the cured product. Total-N, P, K and Mg concentrations of cured leaves were not significantly affected by the form of nitrogen fertilizer used. The results suggested that an initial application of hydrated lime at a rate of 3 t HL ha⁻¹ may ameliorate soil acidity and increase the yield and quality characteristics of Virginia tobacco at least over a 4-year period after application, independent of the form of N fertilizer used.     

添加硫酸铝对稻田土中氟形态及水稻氟吸收的影响

 通过盆栽试验研究了不同硫酸铝用量对水稻植株及稻田土中氟含量的影响。结果表明,水稻植株对氟存在着奢侈吸收的现象,各部位氟浓度的顺序为稻壳＞糙米＞根＞茎叶。在相同氟浓度下,随着硫酸铝用量的增加,水稻植株各部位的氟浓度呈先降低后增加的趋势,在0.4%、0.6%硫酸铝处理下出现最低值,并且与对照差异极显著。土壤中自由态氟和水溶态氟含量随着硫酸铝用量的增加而呈逐渐降低趋势。线性分析表明两种氟与硫酸铝用量呈极显著负相关;而残余态氟则与硫酸铝用量呈极显著的正相关;虽然土壤中可交换态氟含量随着硫酸铝用量的增加呈先增后降的趋势,并在0.2%硫酸铝处理下出现最大值,但是统计分析表明, 0%和0.2%硫酸铝处理间差异不显著,而在0.2%~0.8%硫酸铝处理间差异均达极显著水平。这说明铝对交换态氟的作用以抑制为主;络合态氟、铁锰结合态氟及有机态氟的含量也呈先增加后降低的趋势,最高值出现在0.4%、0.6%硫酸铝处理。相关分析表明,植株各部位的氟浓度与土壤中铁锰结合态氟和有机束缚态氟含量呈显著或极显著负相关。因此,当硫酸铝用量为0.4%~0.6%时（相当于氟铝的质量比为6∶1~4∶3）,植株各部位的氟浓度较低,降氟效果较好;而且此时土壤中水溶态和交换态氟含量相对较低,铁锰结合态和有机束缚态氟含量相对较高,能够减少氟向地下水的渗透,从而降低人畜通过地下水和米饭所摄入的氟量。     

刈割对元谋干热河谷区海狮苏丹草生长及生产性能的影响

以牧草鲜草产量、再生速度、分蘖数等为观测指标,研究不同刈割处理和刈割茬数对元谋干热河谷区海狮苏丹草[Sorghum sudanense(Hay king)Stapf.]生长及生产性能的影响。研究结果表明：海狮苏丹草在干热河谷区具有较好的适应性,在其生长季内可刈割5次;留茬高度和茬数对其再生性能和分蘖能力均有显著影响,其中刈割茬数对其再生速度和分蘖数影响最大,随着刈割茬数增加再生速度显著减慢而分蘖数则明显增加;海狮苏丹草不同留茬高度、刈割茬数对生物量均存在显著差异;就生物量和再生能力来看,海狮苏丹草留茬高度     

播期对不同穗部特征小麦品种(系)生育期和农艺性状的影响

为了解播期对多小穗和寡小穗小麦生育期及农艺性状的影响,对13份不同来源的小麦品种(系)两年分期播种的生育期和6个农艺性状(株高、单株有效分蘖数、穗长、每穗小穗数、穗粒数和千粒重)进行了分析和评价。结果表明,播期的推迟导致材料间出苗期差异变大,抽穗期差异缩小,但开花期和成熟期差异变化不大,各农艺性状值减小。经方差分析,各农艺性状在不同播期和品种(系)间均存在极显著差异,其中单株有效分蘖数的变异系数最大,穗粒数次之,每穗小穗数最小。多小穗材料10-A和寡小穗材料BE89的穗长、每穗小穗数和穗粒数在播期间差异较小。经相关分析,播种至出苗和分蘖至抽穗天数与温度呈极显著负相关,出苗至分蘖和开花至成熟天数与平均日照时间呈显著负相关,抽穗至开花天数与温度和降水量呈显著负相关。经多元逐步回归分析,日最高温和日均温对多小穗和寡小穗材料的分蘖至抽穗天数有显著影响,平均日照时间在开花期、日最高温在成熟期分别对多小穗材料发育有显著影响。由此可见,小穗数特异性材料的每穗小穗数在不同播期下能保持稳定。     

Bis(2,3-dibromo-4,5-dihydroxybenzyl) Ether,a Marine Algae Derived Bromophenol,Inhibits the Growth of Botrytis cinerea and Interacts with DNA Molecules

Bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (BDDE) is a bromophenol isolated from marine algae. Previous reports have shown that BDDE possesses cytotoxic and antibacterial activity. In the present study, we demonstrate that BDDE displays broad-spectrum antifungal activities, especially on Botrytis cinerea. BDDE inhibits the growth of B. cinerea cultured on a solid medium of potato dextrose agar (PDA) as well as on the potato dextrose broth (PDB) medium. Moreover, BDDE decreases the incidence of fruit decay and severity of strawberries infected with B. cinerea. Further studies have revealed that BDDE decreases the germination rate and inhibits the mycelial growth of B. cinerea. The inhibition mechanisms are related to the disruption of the cell membrane integrity in B. cinerea spores and newly formed germ tubes. This study also suggests that BDDE possibly interacts with DNA via intercalation and minor groove binding. The studies provide evidence that BDDE has potential application in the control of gray mold after fruit harvest and the compound could serve as a candidate or lead template for rational drug design and for the development of antifungal agents.