常温真空包装对保持小米储藏品质的影响

为了探究一种有效的小米储藏方法,以晋谷42号小米为试材,采用0.08 mm厚尼龙(polyamide,PA)复合聚乙烯(polyethylene,PE)袋包装,常温((20±2)℃)环境中储藏,研究小米在常规、常规密闭和真空包装储藏120 d品质指标的变化规律。结果表明:相对于常规包装,真空包装储藏有效降低脂肪氧合酶的活性(P<0.05),延缓小米脂质的氧化分解(P<0.05),抑制小米游离脂肪酸含量的升高(P<0.05),较好地保持了小米的水分(P<0.05),延缓了小米黄色素的损耗(P<0.05),较好地保持了小米的亮度(P<0.05)、米黄色(P<0.05)以及弹性(P<0.05)和黏附性(P<0.05);常规密闭包装具有一定的储藏效果,但不及真空包装。因此,常温下真空包装储藏可以有效延缓小米的陈化,保持小米的储藏品质。研究结果为小米储藏,提升小米储藏品质提供了理论依据和技术支持。     

不同施肥处理对“稻花香”食味的影响

以"稻花香"为供试材料,研究了不同施肥处理(T1,常规处理;T2,豆饼处理;T3,豆饼+麦饭石处理)对稻米食味品质的影响。结果表明,T3处理的整精米率高于T1和T2处理,垩白粒率表现为T3T2T1,而碎米率表现为T3T2T1。从稻米的成分来看,蛋白质含量表现为T1T2T3的倾向,3种处理的直链淀粉含量无显著差异,T3处理的评分极显著高于T1和T2处理,T1和T2处理间差异不显著。淀粉糊化特性方面,最高粘度表现为T2T3T1,崩解值表现为T3T2T1,而消减值表现为T3T2T1。品尝试验中,3个处理在米饭外观上的差异不明显,T2、T3处理的香气与T1处理存在显著差异,T2、T3处理的综合评价值极显著高于T1处理。T2处理的味道、粘度和硬度与T1处理差异不显著,而T3处理的味道和粘度与T1处理存在显著差异。     

Low potassium diets with different levels of calcium in comparison with different anionic diets fed to prepartum dairy cows: Effects on sorting behaviour,total tract digestibility,energy metabolism,oxidative status and hormonal response

This study investigated the effects of low potassium diets with different levels of Ca compared to two diets low in dietary cation–anion difference (DCAD) fed prepartum as a strategy to prevent hypocalcemia on sorting behaviour, total tract digestibility, oxidative status and energy and protein metabolism of transition cows. Forty-eight pregnant dairy cows were assigned to 4 treatment groups: Low Ca, low K (LCLK), High Ca, low K (HCLK), Supplementation with anionic mineral mixture (AMS) supplementation with SoyChlor (CAS). After parturition, all animals were fed a standard postpartum diet. Data were collected until 21 DIM. Prepartum urinary pH was significantly reduced by the low DCAD diets, while postpartum Ca homeostasis was affected by the HCLK ration. Feeding AMS induced sorting against particles <1.18 mm in favour of particles >19 mm prepartum. In contrast, cows fed CAS showed an increase in selective consumption of fine particles and sorted against longer particles similar to the HCLK and LCLK groups. Postpartum sorting activity was not affected by the dietary treatments. After calving, apparent digestibility of NDF was significantly reduced in the HCLK group. Prepartum, we observed effects on serum concentrations of non-esterified fatty acids were higher and insulin sensitivity was lower in the AMS group. Blood urea nitrogen (BUN) was decreased in cows fed the CAS ration. Postpartum, we found serum protein to be decreased with the low DCAD diets while BUN was decreased in the CAS group. The low DCAD rations increased prepartum serum malondialdehyde concentrations, while postpartum total antioxidant capacity was lower in the HCLK and the AMS group. From these data, we conclude that AMS decreased prepartum intake due to compromised palatability. Intermediate protein metabolism was affected by the low DCAD diets, while parameters of oxidative stress were probably affected by acid–base balance and Ca homeostasis.     

米饭粒流变特性的试验

通过米饭粒的双面剪切及松弛试验，获得了与米饭粒质构特性相关的流变特性，如硬度、最大剪切力、剪切能、松弛力及松弛时间等，并研究了影响不同品种稻米的米饭粒流变特性的因素。通过多元逐步回归建立了回归方程，同时进行了米饭粒的力学指标与食味值之间的相关性分析，得到了米饭粒流变性质与食味值之间的回归方程，并用于预测稻米的食用品质及进行稻米的食用品质评定。     

糜子的小孢子发生与花粉发育

观察结果表明,糜子小孢子发生与花粉发育的细胞学过程,与稻麦等禾本科作物相似:减数分裂属顺序型,一般形成等面形四分体;也观察到线形、T形及各种倾斜形的四分体;小孢子经两次有丝分裂发育成三核型花粉粒;成熟的花粉粒为球形,具一个萌发孔,直径48(45～52)μm.花粉发育过程中,生殖细胞的运动、淀粉积累时期及花粉粒体积增大动态的观察结果与一些报道不同.糜子的小孢子发生和花粉发育与花药长度存在密切关系,而花药长度随时间呈S形增长方式.本文利用上述关系求得小孢子发生与花粉发育各阶段的经历时间.     

谷子株高及穗部性状主基因+多基因混合遗传模型分析

【目的】株高和穗部性状是影响谷子产量的关键性状。探究谷子株高及穗部性状表型变异的遗传规律,为相关性状的遗传改良与基因定位提供参考依据。【方法】以谷子优质品种豫谷18为共同父本,分别与黄软谷和红酒谷杂交,构建2个分别包含250个家系的重组自交系F₇群体（YYRIL和YRRIL）。采用主基因+多基因混合遗传模型,对YYRIL和YRRIL群体在2个环境下的株高、穗长、穗下节间长、穗码数、穗粒重等5个农艺性状的表型数据进行遗传分析。【结果】5个性状在所有环境中均表现连续变异且存在超亲分离现象,峰度和偏度绝对值小于1,近似正态分布,呈现数量性状的典型遗传特点。性状间相关性分析表明株高与穗长、穗下节间长在所有环境中均呈极显著正相关,穗码数与穗粒重呈极显著正相关。遗传模型分析显示YYRIL和YRRIL群体株高的最适遗传模型分别为PG-AI和PG-A多基因模型,多基因遗传率分别为95.15%和91.27%。2个群体穗码数的最适模型均为PG-AI,多基因遗传率为70.07%—71.58%。穗下节间长在2个群体的最适遗传模型分别为4MG-CEA和3MG-CEA,均为等加性主基因模型。穗下节间长在YYRIL群体的主基因遗传率为9.69%,4对主基因加性效应值相等,均为-0.34,具有负向效应;穗下节间长在YRRIL群体的主基因遗传率为45.78%,3对主基因加性效应值相等,均为1.17,具有正向效应。穗长在YYRIL群体的最适模型为MX2-ED-A,即2对显性上位主基因+加性多基因模型,主基因遗传率为43.56%,多基因遗传率为50.56%。控制穗长的2对主基因加性效应值分别为-1.21、1.68,多基因加性效应较小,为-0.0017;穗长在YRRIL群体的最适模型为MX2-AE-A,即2对累加作用主基因,加性多基因混合遗传模型;穗长的主基因遗传率为46.40%,多基因遗传率为46.91%。控制穗长的第1对主基因加性效应值为1.53,具有正向效应,第1对主基因加性×第2对主基因加性上位性互作效应值是0.60,多基因加性效应值为-0.47,表现为较低的负向遗传效应。穗粒重在YYRIL群体的最适遗传模型为MX2-ED-A;符合2对显性上位主基因+加性多基因模型,主基因遗传率为69.09%,多基因遗传率为12.08%;控制穗粒重的2对主基因加性效应值分别为0.58、5.82,以第2对主基因的加性效应为主,多基因加性效应值为-3.81。穗粒重在YRRIL群体的最适遗传模型为3MG-PEA,即3对部分等加性主基因遗传模型;穗粒重的主基因遗传率为81.10%,3对主基因加性效应值分别为-2.68、-2.68和2.66,前2对主基因的加性效应值相同,且均为负向效应。【结论】谷子株高、穗码数的最适遗传模型相似,均服从多基因遗传,遗传率较高,受环境影响较小;穗下节间长的遗传受主基因控制,主基因遗传率偏低,受环境影响较大,在栽培中应充分考虑环境因素;穗长遗传受主基因和多基因共同控制;穗粒重在2个群体均服从主基因遗传,主基因遗传率较高,可能存在主效QTL。     

切断深层根对黍子根系及地上部营养生长的影响

采用根管土柱栽培的方法,研究了拔节期和抽穗期切断不同深度(20 cm和40 cm)根系对黍子根系整体及地上部营养生长的影响。结果表明,与不断根相比,在抽穗期和拔节期断掉20 cm或40 cm以下根系,均能导致黍子株高、旗叶叶绿素含量、旗叶SOD与POD活性、单株绿叶面积、总根活力、总根长、总根重及产量明显降低,旗叶M DA含量明显增高。抽穗期断深层根对黍子的影响大于拔节期。但同一生育时期不同深度断根处理间黍子产量差异未达显著水平,表明深层根系(40 cm以下根系)对产量的贡献更大。     

山地夏季人工草场山羊放牧适口性研究

在福州北峰的夏季人工草场,通过划区轮牧试验对山羊的适口性进行了研究.试验结果表明,在对杂交狼尾草、甘薯、百喜草等7种牧草进行的适口性评价,甘薯对山羊的适口性最好,表现为嗜食;对杂交狼尾草表现为喜食;羽叶决明、南非马唐、俯仰马唐对山羊的适口性较差.同样,山羊对百喜草、印度豇豆等牧草的不同生育期,其适口性系数也发生变化.     

A minute P application contributes to a better establishment of pearl millet (Pennisetum glaucum (L.) R. Br.) seedling in P deficient soils

Many soils of the semi-arid tropics are deficient in P, and under such adverse conditions, the establishment of pearl millet seedlings is a critical step to achieve satisfactory crop stands. Phosphorus fertilizer is expensive for small holder farmers and is only applied at low rates, insufficient to give satisfactory crop stands. Methods are needed to enhance productivity at low rates of application. Here, we tested the hypothesis that a minute application of P at early seedling stage, equivalent to 125–500 g P/ha, would enhance the plant establishment under P-limiting conditions. We measured the minimum application of P needed to elicit a response of different genotypes. Pot experiments were conducted with pearl millet ( Pennisetum glaucum (L.) R. Br.) hybrids to measure the response to P placed close to the root system, 5 days after sowing (DAS), compared with a non-limiting P control (DAP). The placement treatments were 0, 0.25, 0.50, and 1.0 mg soluble P per seedling, applied as KH₂PO₄ solution. The localized placement of P increased biomass in all three soils tested. In one soil, plant biomass at 1000 μL (1 mg P) reached about 50% of the non limited control. If applied later than 19 DAS the placement had no effect on the plant biomass. Hybrid ICMP 451-P8 was more responsive than hybrid 81B-P6. Placement to 20 inbred lines of pearl millet increased biomass by an average of 105% compared with no placement with large genotypic variation. Although this work was not intended to be a way of applying P fertilizer to pearl millet under field conditions, it showed that applying minute amount of P to pearl millet seedling (equivalent to 125–500 g P/ha) enhanced their establishment and led to improved growth for at least 5–6 weeks after sowing. Further work is in progress to develop a feasible technology for field crops based on the results of this study.     

不同基因型谷子品种(系)对干旱胁迫的响应及抗旱性评价

旨在为旱区谷子生产及抗旱育种提供理论依据。以10个谷子品种(系)为研究对象,采用管栽试验,研究了干旱胁迫对不同基因型谷子生长及产量相关性状的影响。结果表明,在干旱胁迫条件下,参试的10个谷子品种(系),叶绿素含量下降的幅度为4.90%~33.11%,株高降低的幅度为9.56%~30.93%,穗长减小的幅度为5.58%~30.90%,穗粗减小的幅度为3.42%~16.34%,单穗重降低的幅度为7.30%~45.71%,单穗粒重降低的幅度为11.83%~54.72%,出谷率降低的幅度为4.89%~16.60%。抗旱性评价结果表明,‘冀谷31’、‘沧谷5号’、‘冀谷19’等3个品种的抗旱性较好。