适宜机插的优质籼稻品种筛选及其评价指标体系

为了筛选适宜贵州稻区机插的优质籼稻品种，建立适宜机插优质籼稻品种的评价关键指标体系，以近年选育的34个优质籼稻品种为试验材料，在贵州省遵义市湄潭县进行机插试验，对各品种的秧苗素质以及机插条件下水稻分蘖生长、干物质积累、抗倒伏性、产量及其构成因素进行研究。结果表明，机插条件下34个优质籼稻的产量变幅为6.1~10.5 t·hm-2，结合两步聚类算法，以产量为依据将参试品种划分为适宜机插和不适宜机插两类。适宜机插优质籼稻类型主要表现为产量均高于8.25 t·hm-2，其成苗率高、秧苗均匀性好、幼苗健壮；分蘖早生快发，易形成充足的有效穗数；植株能获得较高的花前和花后干物质积累量，并重新分配到籽粒；茎秆粗壮，基部3个节间平均抗折力强，倒伏指数小。综合来看，F优498、晶两优534和蓉18优2348等15个优质籼稻品种适宜贵州地区机插，且适宜机插优质籼稻关键评价指标为：成苗率>85%，秧苗均匀性>1.5苗·cm-2；倒伏指数<150%，基部3个节间平均抗折力>1 500 g；产量>8.25 t·hm-2，有效穗数225×104～300×104 hm-2，每穗粒数>140粒，结实率>75%，成熟期干物质积累量>15 t·hm-2，收获指数>0.45。研究为机插专用优质籼稻品种选育及应用提供理论依据。     

考虑土壤水平衡的灌区水资源优化配置研究

针对内蒙古河套灌区解放闸灌域地下水埋深较浅且矿化度高及黄河水量逐年减少等因素导致的农业用水严重短缺问题,本研究以解放闸灌域玉米为研究对象,耦合Jensen模型与土壤水平衡模型构建灌区尺度灌溉水资源优化配置模型,对不同的地下水埋深及土壤含水量情景下水资源优化配置方案进行研究,并利用Lingo软件编程求解模型。结果表明:当地下水埋深为2.5m时,引黄水量为3.85×10~8 m~3,可以达到5.55×10~8元的净经济效益;而土壤水含量为0.12～0.16时,净经济效益为[5.41,5.67]×108元。优化结果验证了模型在当地可行,并针对河套灌区解放闸灌域的不同土壤含水量与地下水埋深情景分别提供14种配水方案。     

轮叶狐尾藻对水体重金属铅污染的耐性研究

以狐尾藻(Myriophyllum verticillatum)为试验材料,采用液体培养法,研究了不同浓度Pb尾矿液单一胁迫下对其幼苗生长及生理指标的影响,以期为今后在探讨狐尾藻对Pb耐性机理方面提供参考依据和实践指导。结果表明:随着Pb尾矿渗出液单位浓度的升高,狐尾藻幼苗的株高和根长以及干质量整体呈不断下降趋势,其中,在100%Pb尾矿液处理下地下部的干质量较对照下降显著(P0.05)。此时,地上部干质量较对照也呈下降趋势,但整体幅度不大,说明狐尾藻幼苗的生长整体受到明显抑制;随着Pb尾矿渗出液单位浓度的升高,幼苗中光合色素含量逐渐下降且整体均低于对照。在纯Pb尾矿液处理条件下,Chla、Chlb和Car的含量比对照下降了14.6%、29.6%和23.2%;所有处理中幼苗地下及地上部相对电导率与Pb尾矿液浓度成正比且均高于对照。各个处理的地上及地下部Pro含量随着Pb尾矿液浓度增高整体呈上升趋势。其地上和地下部的AsA含量和GSH含量变化呈低浓度上升,高浓度下降的趋势。在25%Pb胁迫处理下,幼苗中AsA含量在地上和地下部均达到最高,与对照相比差异明显(P0.05),较对照增加了93.5%和89.8%。而地上和地下部GSH含量较对照增加了35.7%、4.36%。数据表明,狐尾藻对Pb胁迫下的环境有一定的抗性,可被用于Pb污染环境的生态修复。     

Response of N2O emission to straw retention under two contrasting paddy water conditions: a field experiment over rice–rice-fallow rotation

Paddy and Water Environment - Few studies are available on comprehensive impacts of straw retention and water regimes on nitrous oxide (N2O) emission from rice–rice-fallow rotation systems. A...     

A novel combined recirculating treatment system for intensive marine aquaculture

This study established a pilot‐scale recirculating treatment system that coupled an ecological process with a biological process to achieve adequate water quality and to minimize the water consumption for intensive marine culture. The recirculating treatment system consisted of a settling cell, a biofilter tank, a bivalve tank and gravel beds. The toxic pollutants, threatening the growth of bivalves, were reduced by the settling cell and the biofilter tank, so that the polyculture of shrimp and bivalves could be achieved. The living bivalve tank could function well as a remover of remaining small suspended solids (SS), and other pollutants. As the SS was reduced to a very low level by bivalve tank before the water flowing into the gravel beds, the risk of clogging was prevented. The studies suggested that the system maintained high removal efficiencies of SS, ammonium nitrogen () and nitrite nitrogen () and could contribute to the increase in shrimp yield.     

新型脱叶剂欣噻利在赣北棉花上的应用效果初报

为考察新型脱叶剂欣噻利在赣北的使用效果，以中棉所425为试验材料，进行脱叶剂处理试验。结果表明: 喷施欣噻利1800～2700 mL·hm^－2有较好的脱叶催熟效果，在此范围内其剂量越大，脱叶催熟的效果越好；喷施欣噻利对棉花铃重、铃壳质量、衣分以及纤维品质没有显著影响。     

机采籽棉储运技术质量成本分析

阐述了4种不同籽棉储运技术的原理，采用回归分析法分析了机采散状籽棉储运技术、压模车田间压模储运技术、散状籽棉运输场地压模储运技术、采棉机直接压模储运技术的经济性和优点，并建立起质量成本分析模型，为轧花厂籽棉储存技术应用和改进提供依据。     

Effect of l‐ascorbyl‐2‐polyphosphate supplementation on growth performance,body composition,antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp,Litopenaeus vannamei

An 8‐week feeding trial was conducted to evaluate the effects of ascorbic acid (AsA), in the form of l ‐ascorbyl‐2‐polyphosphate (LAPP) on growth performance, body composition, antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp, Litopenaeus vannamei. Five practical diets (46% crude protein and 7.6% lipid) supplemented with graded levels of AsA (14.64, 48.55, 84.98, 308.36 and 639.27 mg kg^?1 diet) were fed to five replicate groups of L. vannamei (mean initial wet weight 0.57 g). No significant differences were found on growth performance among all treatments. However, whole body lipid content significantly decreased with dietary AsA levels increasing. Activities of total antioxidant capacity, glutathione reductase and glutathione peroxidase were significantly affected by dietary AsA levels. Shrimp fed LAPP‐free diet had higher malondialdehyde content than those fed the diets supplemented with LAPP. Dietary AsA levels higher than 308.36 mg kg^?1 diet increased the survival of shrimps after 1, 2 and 3 h of acute salinity change. Broken‐line regression analysis on survival after 3 h of salinity stress and second‐degree polynomial regression analysis on glutathione reductase data indicated that the optimal dietary AsA requirement of L. vannamei was estimated to be 306.39, 319.75 mg kg^?1 diet respectively.     

Effect of substitution of dietary fish meal by soybean meal on different sizes of gibel carp (Carassius auratus gibelio): digestive enzyme gene expressions and activities,and intestinal and hepatic histology

A 7‐week growth trial was conducted to evaluate the effects of dietary soybean meal (SBM) on digestive enzyme activity of intestinal mucosa, mRNA levels of digestive enzymes in hepatopancreas, and the mid‐intestinal and hepatopancreas histology of gibel carp CAS III (Carassius auratus gibelio). Four different growth phases of gibel carp (initial body weight: fry, 0.8 g; juvenile, 5.0 g; 1‐year‐old, 62.7 g; and broodstock, 135.6 g) were tested. Seven isonitrogenous and iso‐energetic diets were formulated to contain different SBM replacement levels (0%, 20%, 40%, 60%, 80% and 100% of dietary fish meal protein), and another diet (SBMAA) contained all SBM protein and supplied crystalline amino acids. The results showed that the activities of mid‐intestine trypsin, α‐amylase and gamma glutamyl transpeptidase reduced with increased dietary SBM, while the chymotrypsin activity increased first and then decreased. The ultrastructures of intestinal epithelial cells and hepatopancreas cells in fry and broodstock fish were distinctly affected by 200 g kg^‐1 dietary SBM. Supplementation of dietary amino acid to the highest replacement groups was not sufficient to improve digestive and absorptive capacities and growth performance. Gibel carp may be adapted to dietary SBM through increase in gene expression of hepatopancreas digestive enzymes and has potential to utilize proceeded SBM as feedstuffs.