多效唑对太子参光合特性与产量的影响

为促进太子参高产栽培,采用单因素试验研究大田条件下多效唑不同浓度叶面喷施对太子参叶片光合特性与产量的影响。结果表明:叶面喷施多效唑能提高太子参的叶绿素含量,随着多效唑浓度的增高太子参的叶绿素a和叶绿素b均呈上升趋势。多效唑可促进叶片净光合速率、蒸腾速率和气孔导度及胞间二氧化碳浓度的提高,叶片净光合速率、蒸腾速率和气孔导度的增幅相似。各处理净光合速率均高于对照,以100mg/L处理净光合速率最高,为9.49μmol/(m~2·s);胞间二氧化碳浓度随多效唑浓度增大而增大;光饱和点与光补偿点均随着多效唑浓度增高而降低,除50mg/L处理光饱和点[1 000.80μmol/(m~2·s)]高于对照外,其他处理均较对照低;所有处理光补偿点均较对照低;各处理太子参的产量均较对照高,以150mg/L处理的产量最高,为399.8kg/667m~2。     

施硒对水稻外观品质及籽粒硒、镉和砷含量的影响

喷施叶面硒肥是提高水稻籽粒硒含量的有效措施。通过对杂交水稻隆两优华占在孕穗期施用不同浓度的硒叶面肥,研究了施硒对水稻外观品质及籽粒硒、镉和砷含量的影响。结果表明:①施硒能显著提高水稻的整精米率,降低垩白度,当施用量为23 g/hm~2复合硒叶面肥+20 g/hm~2亚硒酸钠时,整精米率达到最高值65.67%,垩白度达到最低值0.65%;②增施硒肥能增加水稻精米和糙米的硒含量,当施用量为23 g/hm~2硒叶面肥+30 g/hm~2亚硒酸钠时,水稻精米和糙米硒含量分别达到最大值为0.784 3 mg/kg和0.816 7 mg/kg,糙米积累硒的能力高于精米;③增施硒肥对水稻精米和糙米中镉和砷含量均没有显著影响,表明籽粒对硒与镉和砷的吸收没有协同作用。同一处理下糙米镉含量均高于精米镉含量,但差异不显著,糙米对重金属砷的累积效果均显著高于精米。     

Characterization of new photosynthesis-inhibiting imidazolidine derivatives. 1. Interpretation of post-emergence herbicidal performance from photosynthesis-inhibiting activity and systemicity

An attempt was made to account for quantitatively measured herbicidal performance of foliage-applied 5-hydroxy-3-methyl-2–oxo-imidazolidine-1-carboxamide derivatives by their photosynthesis-inhibiting activity and systemicity. Photosynthesis-inhibiting activity was estimated from the increase of chlorophyll fluorescence intensity in Chlorella vulgaris Beijer cells measured by a microplate scanner, and systemicity was also evaluated by computer-aided chlorophyll fluorescence imaging. The highest herbicidal performance was recorded for N-cyclohexyl-5-hydroxy-3-methyl-2-oxo-imidazo～idine-l-carboxamide, a compound with the second strongest photosynthesis-inhibiting activity and intermediate systemicity. Though neither photosynthesis-inhibiting activity nor systemicity showed significant correlation with the actual herbicidal performance in simple regression analyses, a high predictability was found for a multiple regression on both parameters as two independent variables, suggesting that these two factors work cooperatively in the field performance.     

Integrated disease management of ascochyta blight in pulse crops

Ascochyta blight causes significant yield loss in pulse crops worldwide. Integrated disease management is essential to take advantage of cultivars with partial resistance to this disease. The most effective practices, established by decades of research, use a combination of disease-free seed, destruction or avoidance of inoculum sources, manipulation of sowing dates, seed and foliar fungicides, and cultivars with improved resistance. An understanding of the pathosystems and the inter-relationship between host, pathogen and the environment is essential to be able to make correct decisions for disease control without compromising the agronomic or economic ideal. For individual pathosystems, some components of the integrated management principles may need to be given greater consideration than others. For instance, destruction of infested residue may be incompatible with no or minimum tillage practices, or rotation intervals may need to be extended in environments that slow the speed of residue decomposition. For ascochyta-susceptible chickpeas the use of disease-free seed, or seed treatments, is crucial as seed-borne infection is highly effective as primary inoculum and epidemics develop rapidly from foci in favourable conditions. Implemented fungicide strategies differ according to cultivar resistance and the control efficacy of fungicides, and the effectiveness of genetic resistance varies according to seasonal conditions. Studies are being undertaken to develop advanced decision support tools to assist growers in making more informed decisions regarding fungicide and agronomic practices for disease control.     

Evaluation of New Container Media for Aglaonema Production

Mandated processing of waste by‐products in the United States has inspired national interest in addressing the effectiveness of using composted biosolids and yard trimmings to grow containerized plants. Diamond bay Chinese evergreen (Aglaonema ‘Diamond Bay’) was transplanted in containers filled with one of eight formulated media (components added by volume). Medium 1 was a standard mix commonly used in Aglaonema production (5:2:3 peat–vermiculite–perlite); medium 2 was formulated on site to contain peat–bark–stalite–rice hulls–coir (2:2:3:1:2); media 3 and 4 contained 40% biosolid–yard waste compost instead of peat and with or without 20% stalite, respectively; and media 5, 6, 7, and 8 were commercially formulated to contain peat–bark–perlite–rice hulls–coir (4:1.5:2.5:1:1, 4:1.5:2.5:1:1, 4:2:2:1:1, and 3.0:2.5:2:1:1.5, respectively). Physical and chemical properties of the eight media were in ranges 50–65% container water‐holding capacity, 2.9–7.8% air‐filled porosity, 55–80% moisture (w/w), 0.11–0.37 g·cm³ bulk density, 0.34–0.96 g·cm³ particle density, 4.2–7.2 pH, 0.12–4.4 dS·m^?1 electrical conductivity (EC), 27.3–54.5 meg/100 g cation exchange capacity (CEC), 17.9–39.0% carbon (C), and 0.22–1.7% nitrogen (N). Medium 4 (40% compost) had 5.5 times more ammoniacal N (NH₄‐N) and 1.7 times more nitrate N (NO₃‐N) than that of the standard commercial mix. At week 8, plants grown in media 2 and 5 were 8.9% to 9.5% taller than plants grown in medium 1 (commercial standard). At week 16, there were no significant differences in plant heights or growth indices among media. At week 24, there were no significant differences in plant height, growth index, visual quality, shoot dry weight, and root dry weight among media. However, cumulative phosphorus (P) leaching from media 1, 4, and 5 was significantly more than leaching from media 2 and 8. This study suggests that compost may serve as a horticulturally suitable and cost‐effective alternative to peat‐based media for Aglaonema production.     

耕作施肥措施对水旱轮作土壤小麦缺锰的影响

利用田间试验研究了不同耕作施肥措施对四川水早轮作土壤小麦缺锰的影响。结果表明,在缺锰条件下喷施锰肥、深耕均显著减轻小麦缺锰症状、改善小麦锰营养,从而提高籽粒产量;秸秆覆盖和猪粪对小麦缺锰症状影响相对较小,小麦产量略高于对照或与对照持平。各处理的整体效果依次为:喷施锰肥>深耕>稻秸覆盖>猪粪和对照。以上结果说明,水早轮作土壤上小麦缺锰与根系不能有效利用底层土壤中的有效锰有关。因此,促进小麦根系下扎及其利用底层土壤有效锰的能力将是避免水早轮作田小麦缺锰的重要途径。不同基因型小麦比较,耐缺锰基因型3317的缺锰症状较轻,植株地上部锰累积量高,而锰敏感基因型川麦22则正好相反,表明3317较强的吸收和累积锰能力正是其耐缺锰的基础。这也从另一侧面说明了利用小麦根系潜力、活化吸收土壤锰在解决水早轮作土壤中小麦缺锰现象中的重要性。     

Scion-rootstock relationships with respect to height growth and foliar concentrations of nitrogen and phosphorus in reciprocal grafts of Pinus caribaea var. hondurensis

Both scion and rootstock clones significantly influenced scion elongation and concentrations of nitrogen and phosphorus in the scion foliage. Scion clone was the more important determinant. Scion clone × rootstock clone interactions were not significant. The ability of a clone to elongate as a scion was not correlated with its capacity to promote or retard scion elongation when used as a rootstock. Genetic differences in foliar nutrient concentrations appeared to reflect levels of nutrient demand, rather than the ability of roots to absorb nutrients. Nutrient demand of the rootstock can also explain negative correlations between nitrogen levels in rootstock clones and levels of both nitrogen and phosphorus in the scions. There was no significant relationship between scion elongation and foliar nitrogen concentrations of either rootstock or scion. The weak relationship between scion elongation and concentration of phosphorus in the rootstock apparently resulted from tissue dilution.     

多效抗旱驱鼠剂室内促长效果研究

室内用多效抗旱驱鼠剂对小麦、黄豆、油松、侧柏种子进行浸种、拌种处理。结果表明，300x的林用型和200x的农用型RPA对侧柏种子浸种效果最好，30x的林用型和80x的农用型RPA拌种效果最好，经检验分析，差异显著；500x的林用型和600x的农用型RPA对油松促长效更为明显，发芽率比对照提高25．2％－27．0％，平均高生长增加2．1－2．8cm，拌种型的两种药剂6个浓度对油松的发芽及生长影响比较明显，30x的林用型和40x的农用型可以使油松发芽率提高27．7％－29．8％，苗高增长0．6－1．3cm；对黄豆的发芽率提高12．0％－17．0％、13．8％－23．2％；侧根数量增加0．2－2．6、0．3－1．6条，平均苗高及生物量也有不同程度的提高；浸种型的RPA使小麦发芽率提高13．3％－23．3％，苗高增长5．1－7．5cm，根长增加0．6－1．8cm；拌种型RPA发芽率提高9．3％－22．6％，苗高增长4．7－6．6cm，根长增加0．4－1．6cm。     

杉木幼龄林叶片营养元素含量与林木生长的相关性

本文重点论述丘陵立地条件下 ,1、2代杉木幼龄林高生长、当年高生长、胸径生长与叶片中营养元素N、P、K、Ca、Mg、Cu、Mn、Zn、Fe含量的相关关系 ,进而从林木营养这个角度 ,为提高林木产量、防治地力衰退提供可靠的科学依据。研究结果表明 :2代杉木幼龄林生长与N、P、Mg、Cu、Mn、Fe含量呈密切的正相关。 1代杉木幼龄林生长虽与P、Mg、Cu、Mn、Fe含量呈正相关 ,但复相关系数数值偏低。也就是说土壤养分含量尚没有明显影响 1代杉木幼龄林正常生长     

不同基肥及追肥配比对凤梨生长、产量和品质的影响

为研究不同基肥及追肥配比对凤梨生长、产量及果实品质的影响,以台农17凤梨为研究对象,分别设基肥试验和追肥试验,明确最佳的凤梨施肥模式。基肥试验设复合肥、“劲久”控释肥、羊粪+复合肥和“沃丰康”生物有机肥+复合肥4种肥料组合,每种组合根据总氮含量设100% N、75% N与50% N三种梯度,其中不添加基肥为CK1,共计13个基肥处理。追肥试验设T1（促花肥+开花肥+结果肥）、T2（开花肥+结果肥）、T3（促花肥+结果肥）,其中不施用追肥为CK2,共4个追肥处理。结果表明,在100% N水平下,以11 250 kg·hm^-2羊粪+1 875 kg·hm^-2复合肥作为基肥,凤梨的生长、产量及果实品质最佳。移栽135 d后,凤梨的叶尖高度增加了28.25%,总叶片数增加59.09%,最大叶长增加16.00%,最大叶宽增加42.55%。凤梨产量达58.62 t·hm^-2,较CK1增加20.22%,平均单果重达（1.86±0.32）kg, 果长、果径与芯径分别达（231.47±44.28）mm、（125.62±33.24）mm和（41.16±4.13）mm。此外凤梨的果实品质也最佳,果肉可溶性固形物达（12.6±0.4）%,可滴定酸达（0.50±0.11）%,维生素C达（29.1±6.7）mg·kg^-1。而在75%N水平或50%N水平下,“沃丰康”生物有机肥+复合肥处理的部分凤梨指标更佳。作为追肥,T1的效果最佳,较于追肥前,追肥后的凤梨叶尖高度、总叶片数、最大叶长叶宽分别增加20.18%、184.87%、21.95%和61.25%,产量较CK2增加6.62%。凤梨单果重（1.62±0.33）kg,果长、果径和芯径分别达（183.52±29.35）mm、（123.58±15.68）mm和（40.58±8.39）mm。凤梨果肉可溶性固形物（13.1±0.9）%,可滴定酸（0.47±0.12）%,维生素C含量（28.9±3.2）mg·kg^-1。本研究表明,适用于宁波本地凤梨的最佳施肥方式为以11 250 kg·hm^-2羊粪+1 875 kg·hm^-2复合肥作为基肥,同时添加少量生物有机肥,并辅以促花肥、开花肥和结果肥追施。