吊挂时间对蛋鸡与肉鸡宰后肌肉品质的影响

为国内禽类清真屠宰企业提供数据指导和帮助,该文采用两因素可重复裂区试验设计,以淘汰蛋鸡和AA肉鸡(arbor acre broiler,AA broiler)2个鸡种为主区,5个吊挂时间(0、30、60、90、120 s)为裂区,研究吊挂时间对淘汰蛋鸡与AA肉鸡宰后肌肉品质的影响,结果表明,随着吊挂时间的延长,AA肉鸡在吊挂90 s时,体温变化、宰后24 h pH值、红度值、滴水损失、蒸煮损失显著增大,自由水含量、肌酐酸(inosine monophosphate,IMP)含量显著减小(P<0.05);当吊挂120 s时,淘汰蛋鸡宰后24 h pH值、红度值、蒸煮损失显著增大,IMP含量显著减小(P<0.05).主效应和交互作用分析结果表明,鸡种对体温变化、亮度值、滴水损失、蒸煮损失、结合水含量、不易流动水含量、自由水含量、IMP含量影响显著(P<0.05),吊挂时间对体温变化、红度值、滴水损失、蒸煮损失、自由水含量、IMP含量影响显著(P<0.05),鸡种与吊挂时间的交互作用对红度值、滴水损失、自由水含量、IMP含量影响显著(P<0.05).根据研究结果,建议AA肉鸡适宜的吊挂时间为12~60 s,淘汰蛋鸡适宜的吊挂时间为12~90 s,研究结果为提高宰后鸡肉品质提供参考.     

运输季节对生猪应激及猪肉品质的影响

为了研究运输季节对猪宰前应激及宰后猪肉品质的影响,该文以杜大长三元杂交猪为对象,测定了夏、秋和冬3个季节运输条件下猪的血液生化指标、血细胞系数以及宰后猪肉温度、p H值、保水性、色泽和剪切力的变化。结果表明:秋季运输猪血液中白细胞数、血红蛋白、红细胞压积、葡萄糖、促肾上腺皮质激素和皮质醇浓度显著低于夏季和冬季组(P0.05),胴体表面皮肤损伤也显著降低(P0.05)。运输季节对宰后猪肉胴体温度、p H值、色泽及保水性有显著性影响(P0.05)。与秋季运输相比,夏季运输猪宰后45 min胴体温度、滴水损失率、L值显著升高,a*值和剪切力显著下降(P0.05);冬季运输猪宰后猪肉a*值增加(P0.05),但滴水损失率与秋季组相比并无显著性差异(P0.05)。因此猪在秋季运输能显著降低宰前动物应激,提高宰后猪肉品质,夏季和冬季如能对运输环境分别进行防暑和保暖处理可能会对猪应激反应和猪肉品质产生积极的作用。该研究结果对于屠宰行业实际生产过程中缓解生猪宰前运输应激,改善动物福利以及提高猪肉品质提供参考。     

不同处理方式对虾蛄脱壳效率及肌肉品质的影响

为研究超高压、热烫、冻藏3种不同的前处理方式对虾蛄脱壳效率及肌肉品质的影响,通过对脱壳时间、虾蛄仁得率、汁液流失率、虾蛄仁质构、色泽和肌原纤维蛋白含量等进行分析,以确定合适的虾蛄脱壳前处理方式。结果表明,与热烫、冻藏处理相比,超高压前处理能较好的缩减虾蛄脱壳时间,降低汁液流失率,提高虾蛄仁得率及其完整性,同时超高压处理能较好的提升虾蛄仁的硬度、弹性、咀嚼性和黏聚性。当压强为350 MPa、保压时间为8 min时,超高压处理对虾蛄脱壳效率及肌肉质构的提升效果最好;超高压处理后虾蛄仁pH值和水分含量略有增加,而其肌原纤维蛋白含量有不同程度的下降。综合考虑,350 MPa保压8 min的超高压前处理,能在提高虾蛄脱壳效率的同时较好的保持其肌肉品质。本研究结果为辅助虾蛄高效脱壳及超高压技术在水产品加工中的应用提供了依据。     

用DNA差异显示技术分离、测序和鉴定猪的两个新分子标记及其与性状的关联分析

为了寻找更多的和性状关联的猪候选基因或分子标记,用DNA差异显示技术扫描140头大白×梅山F2猪的DNA,发现了2个与猪的性状具有显著关联的分子标记,并对这2个分子标记进行测序和鉴定.标记1与最后肋骨处估测背膘厚(P＜0.01)、倒数三四肋骨处估测背膘厚(P＜0.01)、估测瘦肉率(P＜0.01)、骨重(P＜0.05)、骨率(P＜0.05)、肥肉重(P＜0.05)、肥肉率(P＜0.05)、瘦肥比率(P＜0.05)、肩部最厚处背膘厚(P＜0.05)、6～7胸椎间背膘厚(P＜0.01)等性状关联.标记2与背最长肌pH值(P＜0.05)、失水率(P＜0.05),系水力(P＜0.05),背最长肌肉色评分(P＜0.05),背最长肌含水量(P＜0.05)、肋骨数(P＜0.05)骨率(P＜0.05)、胸腰椎结合处背膘厚(P＜0.05)、胃净重(P＜0.01)等性状关联.经与GenBank进行Blast比较,这2个标记与已知的猪基因或基因组序列没有明显的同源性,提交到GenBank,登陆号分别为CN605659和AY626262.研究所用的方法为揭示新的猪候选基因或分子标记提供了一条新的途径.     

基于iTRAQ技术的不同耐热性水稻花药差异蛋白分析

为从蛋白质水平揭示耐热与热敏感水稻花药响应高温胁迫的分子机制,本研究以耐热水稻品系996和热敏感水稻品系4628为材料,采用iTRAQ技术对高温和适温条件下水稻花药进行差异蛋白质组学分析。结果表明,在996高温-996适温、4628高温-4628适温、996高温-4628高温和996适温-4628适温4个比较组中,共筛选到957个差异表达蛋白,其中上调表达蛋白398个,覆盖率达20%以上的蛋白占鉴定总蛋白的50.96%。GO分析显示,抽穗开花期花药差异蛋白主要集中于代谢过程和细胞过程,在细胞组成方面主要分布于胞内部分、细胞器和细胞,分子功能主要涉及催化活性、绑定等。花药差异蛋白通路分析显示,来源于bZIP和DOF家族的2个转录因子差异表达,DOF家族基因上调,bZIP家族基因下调;18个HSPs基因中大部分表达上调;与植物激素和信号传导相关基因大部分表达下调;10个活性氧(ROS)相关基因中5个表现为上调;与次生代谢相关基因大部分下调。本研究结果为揭示水稻花药高温胁迫的应答分子调控机制提供了一定的理论基础。     

Role of phospholipase A2 in the induction of drip loss in porcine muscle

The role of phospholipase A2 in the induction of drip loss from pig muscle has been investigated. In samples from porcine M. longissimus dorsi, total PLA2 activity as well as mRNA and protein levels of the group VIA iPLA2 (iPLA2-VIA) increased during the initial 4 h post-mortem period. Morphological studies of porcine muscle showed that at 4 h post-mortem, gaps had formed between muscle fibers and that the sarcolemma membrane borders appeared blurred. At the same time iPLA2-VIA protein levels were increased inside muscle fibers and at the sarcolemma. iPLA2-VIA mRNA abundance in samples from different breeds of pigs with variations in drip loss revealed no clear correlation between drip loss level and iPLA2-VIA expression. Together, these data indicate that during the post-mortem period, iPLA2-VIA expression and activity is increased at the muscle fiber membranes. PLA2 activity may affect membrane permeability and consequently the progression of drip formation in porcine muscle.     

Consumption of oxidized oil increases oxidative stress in broilers and affects the quality of breast meat

A total of 120 4-week-old broiler chickens were allotted to 12 pens and fed one of three diets including control, oxidized diet (5% oxidized oil), or antioxidant-added diet (500 IU vitamin E) for 2 weeks. Blood samples were collected at the end of feeding trial, and breast muscles were sampled immediately after slaughter. Breast meats were also collected 24 h after slaughter and used for meat quality measurements. Oxidative stress in blood, lipid and protein oxidation, and sarcoplasmic reticulum Ca2(+)-ATPase (SERCA) activity of breast muscle were determined. The oxidized diet increased oxidative stress in blood and increased carbonyl content in breast meat compared with the other two dietary treatments (P < 0.05). Lipid oxidation of breast muscles with the antioxidant-supplemented diet was lower than that with the oxidized and control diet groups (P < 0.05). Meat from birds fed the oxidized diet showed higher drip loss after 1 and 3 days of storage and greater 0-1 h post-mortem pH decline (P < 0.05). Significant differences in specific SERCA activity in breast muscles from birds fed control and oxidized diets (P < 0.05) were detected. This suggested that dietary oxidized oil induced oxidative stress in live birds and increased lipid and protein oxidation in breast muscle. Decrease in SERCA activity in breast muscles due to oxidative stress in live animals accelerated post-mortem glycolysis, which sped the pH drop after slaughter and increased drip loss, indicating that oxidation of diet can cause PSE-like (pale, soft, and exudative) conditions in broiler breast muscles.     

Cellular model for induction of drip loss in meat

Drip loss from porcine muscle (M. longissimus dorsi) contained high concentrations of K(+) ( approximately 135 mM) and organic osmolytes, for example, taurine ( approximately 15 mM), as well as significant amounts of protein ( approximately 125 mg.mL(-1)). Thus, the drip reflects release of intramuscular components. To simulate events taking place at the time of slaughter and leading to release of osmolytes and subsequent formation of drip loss, C2C12 myotubes were exposed to anoxia and reduction in pH (from 7.4 to 6.0). Anoxia and acidification increased the cellular Ca(2+) concentration ([Ca(2+)](i)) at a rate of 22-32 nM.min(-)(1). The anoxia-induced increase in [Ca(2+)](i) was mainly due to influx via sarcolemmal Na(+) channels. As mammalian cells swell and release lysophospholipids during anoxia, C2C12 cells and primary porcine muscle cells were exposed to either hypotonic shock or lysophosphatidylcholine (LPC) and the release of taurine was followed. The swelling-induced taurine efflux was blocked in the presence of the anion channel blocker (DIDS), the 5-lipooxygenase inhibitors (ETH 615-139 and NDGA) but unaffected by the presence of vitamin E. In contrast, the LPC-induced taurine release was unaffected by DIDS but abolished by antioxidants (butylated hydroxytoluene and vitamin E). Thus, stress-induced taurine release from muscles may precede by two different mechanisms, one being 5-lipooxygenase dependent and the other involving generation of reactive oxygen species. A model for the cellular events, preceding formation of drip in meat, is presented.     

猪UCP3基因多态性及其与脂肪沉积、肉质性状的相关分析

在QTL定位的基础上选取猪解偶联蛋白3(UCP3)作为控制脂肪沉积性状和肉质性状的候选基因。对猪UCP3基因的部分编码区进行了测序，在395 bp处发现了1个cSNP位点。该cSNP位点发生G→A突变，并导致相应编码氨基酸由甘氨酸→精氨酸的改变。该位点可以被限制性内切酶SmaⅠ识别。利用PCR-RFLP方法，对186头大白×梅山F2资源家系进行UCP3片段SmaⅠ位点分析，发现AA、AB和BB三种基因型，其中A等位基因频率0.56，B 0.44。经统计分析发现，在该F2群体中，UCP3 SmaⅠ位点多态性与脂肪沉积性状中胸腰椎间膘厚、臀部膘厚显著相关；与肉质性状中的肌内脂肪、系水力和失水率显著相关。UCP3 SmaⅠ位点主要表现为加性效应，基因型AA降低膘厚，提高系水力和降低失水率，但同时也降低肌内脂肪含量。     

饲喂沼渣源饲料对猪胴体品质、肉质性状及营养成分的影响

以杜长大三元杂交猪为对象, 研究了饲喂沼渣源配合饲料对猪胴体品质、肉质性状及营养成分的影响.结果表明, 饲料添加不同量的沼渣对猪屠宰率和胴体长无显著影响(P>0.05), 但显著降低了瘦肉率、后腿比例和眼肌面积(P<0.05), 显著提高了背膘厚.饲料添加沼渣显著降低了肌肉颜色和熟肉率, 显著提高了滴水损失和剪切力值, 且添加量越多效果越明显;同时, 添加沼渣对肌肉失水率、pH无显著影响, 但大理石纹评分对照组和沼渣组差异显著.对猪肉营养成分测定结果表明, 添加沼渣显著降低猪肉粗蛋白质、粗脂肪和水分含量, 而对粗灰分含量无显著影响.因此, 猪日粮中添加沼渣降低了胴体品质、肉质性状以及营养价值, 如果将其应用到生产中, 需要解决胴体品质、肉质和营养价值下降的问题.     

待宰时间和致晕方式对生猪应激及猪肉品质的影响

国内外对于生猪宰前因素已经做过大量的研究,但总体来讲,对于待宰时间的研究一直没有形成定论;由于生产成本等问题,国内对于CO2致晕的应用与研究均较少;对于不同的电击晕方式,在同一体系下的成批量的比较涉及很少,另外对于应激指标的选择一直没有统一的标准。该文研究了在电击晕、二氧化碳致晕和不同待宰时间(3、6和12h)条件下,杜大长三元杂交猪血液应激指标和猪肉品质的变化。结果显示:待宰3h的生猪血液指标显著低于另外2种方式,而二氧化碳致晕方式使得生猪血液中乳酸含量、肌酸激酶含量、皮质醇含量和乳酸脱氢酶含量显著低于不击晕和电击晕方式。不同待宰时间对胴体背最长肌宰后24h的温度、pH值、蒸煮损失、明亮度、红色度和黄色度没有显著影响(P>0.05),但是待宰3h的生猪胴体宰后45min的pH值和温度明显较低,汁液损失和剪切力也显著小于待宰6和12h的值;而与不击晕和电击晕方式相比,二氧化碳致晕产生的猪肉宰后45min的pH值和温度较低、汁液损失较大、明亮度较大、红色度和黄色度值较小。因此生猪待宰3h并通过二氧化碳致晕产生的应激反应与猪肉品质影响最小。生产中应加强对待宰时间和致晕方式的控制,并注意利用各种处理方法对肉品质影响的协同作用,从而最大程度实现猪肉品质的改良。     

土壤微生物功能群及其研究进展

功能群研究最早应用于植物生态学,后应用到微生物生态学中。微生物功能群指在物质流中具有特定生物学功能的微生物集合体,这种分类与生物分类学原则无关,只是指它的生物学功能相同或相近,如固氮微生物功能群、溶磷微生物功能群、氨化微生物功能群及纤维素降解微生物功能群等。国内外有关微生物功能群的研究报道主要涉及到草地、农田及森林等生态系统;研究微生物功能群的方法有应用选择性培养基进行分离培养,也有在新鲜土壤中接种特定底物并连续记录底物的利用情况,从而评价土壤原位具有特殊代谢功能的微生物生物量或利用分子生物学技术进行研究。微生物功能群的研究在工业、农业、环境治理、医学及基因工程方面均有重要的现实意义。笔者认为将有更多的学者将目光投向微生物功能群的研究。     

Heat shock protein B1 and its regulator genes are negatively correlated with intramuscular fat content in the longissimus thoracis muscle of Hanwoo (Korean cattle) steers

In previous proteomic studies, heat shock protein β 1 (HSPB1) was detected as a candidate protein related to meat quality in cattle. This study sought to determine if its gene expression was associated with intramuscular fat content in the longissimus thoracis muscle of Korean cattle (Hanwoo). Tissue from two groups of 10 steers each, low-marbling (mean intramuscular fat content, 7.4 ± 1.5%) and high-marbling (23.5 ± 2.8%), were used for immunoblotting, real-time PCR, and statistical analyses. HSPB1 expression in both mRNA and protein was shown to be negatively related to intramuscular fat content (P < 0.05). Pathway analysis found two genes, TNF receptor superfamily member 6 (FAS) and angiotensinogen (AGT), that were regulators of the HSPB1 gene. The expression of the two genes showed a negative correlation with intramuscular fat content (P < 0.05). These results suggest that HSPB1, FAS, and AGT may be good candidate genes associated with intramuscular fat content in the longissimus muscle of Korean cattle.     

pH Dependence of the progression in NMR T(2) relaxation times in post-mortem muscle

Continuous NMR T(2) relaxation measurements were carried out on seven rabbit longissimus muscle samples in the period from 25 min to 28 h post-mortem at 200 MHz for (1)H. To display differences in post-mortem pH progress and extent of changes in water characteristics during conversion of muscle to meat, three of the seven animals were pre-slaughter injected with adrenaline (0.5 mg/kg live weight 4 h before sacrifice) to differentiate muscle glycogen stores at the time of slaughter. Distributed analysis of T(2) data displayed clear differences in the characteristics of the various transverse relaxation components dependent on progress in pH, as did the water-holding capacity of samples 24 h post-mortem. This reveals a pronounced effect of the progressive change in pH on the subsequent development in physical/chemical states of water during the conversion of muscle to meat. Finally, the relaxation characteristics are discussed in relation to supposed post-mortem processes of protein denaturation.     

标准化法和主成分法评估牦牛不同部位分割肉品质

为了研究牦牛不同部位分割肉的品质特征,该研究测定了牦牛辣椒条、上脑、眼肉、外脊、里脊、小黄瓜条、大黄瓜条、米龙、霖肉9个部位分割肉的剪切力、蒸煮损失、失水率、L*、a*、b*、蛋白、脂肪、含水率9项品质特性,并通过方差分析法、标准化法、主成分法研究其品质特征。结果表明,除了脂肪和含水率外,其余7项品质特性均存在显著差异性（P＜0.05）。标准化分析结果表明小黄瓜条、大黄瓜条、米龙、霖肉4个后部肉具有相似特征,具有较好的嫩度、较高的蛋白含量、中等水平的持水能力。主成分分析共提取出3个主成分因子PC1（34.69%）、PC2（25.97%）、PC3（19.12%）,其中PC1可明显区分出中部肉与后部肉差异,根据因子载荷,牦牛肉化学组成（蛋白、脂肪、含水率）与这一差异密切相关。可以得出以下结论：不同部位牦牛肉品质存在差异,这一差异与其在牦牛胴体上的相对位置有关,而牦牛胴体的后部肉品质优于其他部位,因此可以作为开发高档产品的原料来源。     

Relationship between meat structure, water mobility, and distribution: a low-field nuclear magnetic resonance study

Nuclear magnetic resonance (NMR) measurements were carried out on pork longissimus muscle, which pre rigor had been manipulated to various muscle lengths, to investigate the relationship between the microstructure of meat and the NMR T(2) relaxation. Distributed exponential analysis of the NMR T(2) relaxation data revealed the existence of three distinct water populations: T(2b), T(21), and T(22). A high, significant correlation was found between the T(21) time constant and the sarcomere length (r = 0.84) and calculated ration of myofilament lattice volume in the I-band and A-band regions, respectively (r = 0.84), considering sigmoid relationships. The result implies that the T(21) time constant mainly is determined by the structure of the myofilament lattice and so strongly supports a previously proposed theory that the T(21) population corresponds to water located within a highly organized myofibrillar protein matrix including actin and myosin filament structures. A high correlation was also found between the T(22) population and the water-holding capacity (WHC) (r = 0.76), which suggests that the WHC is mainly determined by the amount of loosely bound extramyofibrillar water. However, the correlation between NMR T(2) parameters and WHC was further increased (r = 0.84) by including the T(21) time constant in the correlation analysis. This implies that the formation of drip loss is an ongoing process involving the transfer of water from myofibrils to the extracellular space and is affected by structural features at several levels of organization within the muscle tissue. This study demonstrates the advantages of NMR T(2) relaxation as an effective technique for obtaining further understanding of the relationship between the microstructure of meat, its WHC, water mobility, and water distribution.     

滴灌枸杞对龟裂碱土几种酶活性的改良效应

在盐碱地改良利用过程中,有必要研究土壤酶活性变化,以评价土壤环境质量的改善。龟裂碱土重度盐碱荒地主要分布在我国西北旱区,该土壤碱化度高,结构差,导水率极低。2009年,采用滴头下设置沙穴的方式滴灌种植枸杞,开垦利用该盐碱荒地。2011年枸杞生长季末,在不同种植年限地块土壤剖面上网格状密集取土,进行土壤脲酶、碱性磷酸酶和蔗糖酶活性的测定。结果表明,未种植土壤3种酶活性极低;滴灌种植之后,随着根区土壤水盐特性和养分状况的改善,土壤酶活性显著增加。就整个土壤剖面而言,土壤酶活性自根区向四周逐渐降低,表现出较大的空间变异性。相关性和通径分析结果显示,土壤p H始终是影响该土壤酶活性的主要因子,且在p H7.38~10.00的范围内,3种酶活性随土壤p H的增大呈指数式减小(p0.01)。总之,滴灌种植枸杞之后,龟裂碱土重度盐碱荒地土壤生物学性质得到显著改善。     

冰温结合不同比例氧气气调对冷却肉的保鲜效果

试验研究了在冰温基础上结合不同含氧比例气调对冷却猪肉保鲜的影响,试验设置冰温、冷藏（4℃）、真空包装+冰温、20%CO2+80%O2（高氧）+冰温、20%CO2+20%O2+60%N2（低氧）+冰温、20%CO2+80%N2（无氧）+冰温6个试验组,测定菌落总数、挥发性盐基氮、汁液流失率、保水能力和色差。结果表明：冰温条件下高氧和低氧的菌落总数24 d还未超过冷却肉卫生标准,且两组之间无显著差异（P＞0.05）;在整个贮藏期内高氧气调和低氧气调可以维持冷却肉的色泽在一个小的范围内变化;高氧气调和低氧气调8 d后汁液流失率显著高于单纯冰温和无氧气调（P＜0.05）,高氧气调12 d后汁液流失率显著高于低氧气调（P＜0.05）,同时高氧气调8 d后持水能力显著大于低氧气调（P＜0.05）。在冰温条件下,80%O2和20%O2都能长时间维护冷却肉的色泽,均能较好抑制微生物的增殖,但在汁液流失率、保水能力方面各有优势。     

超声联合滚揉腌制对鸡胸肉品质的影响研究

为了改善淘汰蛋鸡鸡胸肉的品质,探明超声联合滚揉腌制对鸡胸肉保水性、嫩度和挥发性风味成分的影响。本研究基于不同腌制工艺下鸡胸肉腌制液的吸收率和肉品质(蒸煮损失、离心损失、剪切力)的差异,通过低场核磁共振、组织切片和顶空固相微萃取气相质谱联用(HS-SPME-GC-MS)技术分析了鸡胸肉品质发生变化的原因。结果表明,滚揉腌制和超声联合滚揉腌制均加快了腌制速率,提高了鸡胸肉的保水性和嫩度,原因可能是滚揉和超声波的机械作用促进了水分的迁移和均匀分布,破坏了肌纤维结构,并且超声和滚揉具有协同效果。此外,采用滚揉腌制和超声联合滚揉腌制对鸡胸肉挥发性风味成分的种类及含量都有一定影响。本研究结果为改良鸡肉品质、开发低磷酸盐含量的鸡肉制品提供了理论参考。     

与甜瓜性别分化相关植物激素生物合成途径分析

甜瓜性别分化是由多因素构成的一个复杂的网络系统调控,受到多种环境因素及激素水平的影响。本研究利用甜瓜(Cucumis melo L.)WI 998×TopMark 构建重组自交系群体,通过第二代高通量测序技术对F2S6群体中雌雄异花同株及全雌系植株的转录组测序,比较差异表达基因,分析与性别差异表达相关的植物激素合成途径。结果显示,雌雄异花同株获得77376 条 Unigenes,平均长度为 435 bp;全雌系转录组测序获得 80 825 条 unigenes,平均长度为 509 bp。比较雌雄异花同株与全雌系转录组,发现共有 8966个基因差异表达,4 296 个基因下调,4 670 个基因上调。对差异基因进行基因本体论(GO)功能分类,发现2 352 条 Unigenes 归入到生物学过程,4 107 条 Unigenes 归入到细胞学过程,2 507 条 Unigenes 归入到分子功能。差异表达基因共参与 121 个 Pathway,发现赤霉素(gibberellin, GA)合成途径中 GA3 - 氧合成酶(GA3-ox)(MU3674)、GA7- 氧化酶(GA7-ox)(MU36987)、GA2- 氧化酶(GA2-ox)(MU13098/MU13099)、GA20-氧化酶(GA20-ox)和 GA2- 氧化酶(GA2-ox)(MU33020)等基因差异表达;共有 38 个基因在脱落酸(abscisicacid, ABA)合成途径中差异表达,其中 19 个上调,19 个下调;油菜素内酯(brassinolide, BR)合成途径中,MU22012 (cytochrome P450),MU26893 (cytochrome P450) 基因上调 ,MU56098 (cytochrome P450,CYP724B3),MU76596(CYP724A1)下调。本研究还发现参与甜瓜性别表达,分别与赤霉素、脱落酸、油菜素内酯及玉米素等多种激素合成、信号传导等代谢途径相关。研究结果为分析甜瓜决定性别分化的可能机理,为下一步研究甜瓜性别修饰基因的克隆,提供重要依据。