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991.
以菌丝生物量为评价指标,对液体摇瓶培养柱状田头菇(Agrocybe cylindracea)的碳氮源、接种量及培养时间进行研究,筛选出培养的适宜条件,并将外源激素6-苄基腺嘌呤(6-benzylaminopurine,6-BA)、2,4-二氯苯氧乙酸(2,4-dichlorophenoxyacetic acid,2,4-D)、吲哚乙酸(indole-3-acetic acid,IAA)、萘乙酸(α-naphthaleneacetic acid,NAA)添加于液体培养基中探讨其加快菌丝体繁殖的可能性。结果表明,柱状田头菇液体发酵适宜的培养基组成为(/L):马铃薯200 g,小麦粉20 g,酵母粉1 g,MgSO43 g,KH2PO42 g,VB110 mg。培养条件以250 mL摇瓶装液量100 mL,接种量100 mL/L,培养9 d终止发酵为宜;外源激素NAA能极显著提高菌丝生物量。 相似文献
992.
西瓜3种性型花器官性别分化的细胞形态学观察 总被引:1,自引:0,他引:1
以西瓜3种性型(雌雄异花同株系、全雌系和完全花雄花系)的雄花、雌花和完全花3种花芽为材料,制成石蜡切片,进行西瓜花芽不同发育时期的细胞形态学观察。结果表明:西瓜3种性型之间性别分化起始及同种性别之间花器官发育过程并没有明显的形态学差异。雄花、雌花和完全花3种花芽分化首先要经过一个两性期,即雄蕊原基和雌蕊原基同时存在时期,在两性期之前三者不存在明显的形态学差异;当花芽长度为0.8~1.0mm时两性期结束,开始雄花、雌花和完全花的差异发育,此后雄花和完全花的雄蕊原基快速增大,雌花和完全花的雌蕊原基开始分化为柱头和子房。在3种花芽发育过程中,完全花的花芽在两性期后明显比同时期的雄花、雌花的花芽长度更长。全雌系中的"畸形雌花"出现在两性期后,雌蕊原基的凹陷发育过程受阻,而本该停止发育的雄蕊原基继续分化,最终发育成可产生少量成熟花粉粒的雄蕊。 相似文献
993.
采用气相色谱法测定全雄株(ffMMaa)、雌雄同株(ffMMAA)、全雌株(FFMMaa、FFMMAA)和两性花株(FFmmAA)不同基因型近等基因系材料间的乙烯释放速率,探讨乙烯与黄瓜性型的关系。结果表明,不同近等基因系乙烯释放速率之间存在显著性差异。全雄株78♂(ffMMaa)的乙烯释放速率较低;雌雄同株406(ffMMAA)四叶一心期的乙烯释放速率大于两叶一心期;含6.33个F基因拷贝数的雌性系10098♀(FFMMaa)与F基因拷贝数为2.15的雌性系WI1983G(FFMMAA)相比,乙烯释放速率较低;雌性系WI1983G(FFMMAA)的乙烯释放速率极显著高于两性花株WI1983H(FFmmAA),两性花株WI1983H又极显著高于雌雄同株WI1983GM(ffMMAA);说明黄瓜性别表型与内源乙烯密切相关。从试验结果推断:雄株(ffMMaa)中乙烯释放速率低可能与A基因失活相关,雌性系(FFMMaa)乙烯释放速率可能受A/a基因的调控,两性花株(FFmmAA)中虽然M基因失活但内源乙烯释放速率并未降低很多,可能F基因产生的内源乙烯没有直接作用到两性花的雄蕊上。 相似文献
994.
桃种子层积中激素的变化及其与破眠的关系 总被引:6,自引:0,他引:6
本文研究了桃种子层积过程中内源脱落酸(ABA)和赤霉素类物质(GAs)含量的变化。结果表明,未层积种子中含有高浓度的ABA和低水平的GAs。低温(4℃)层积过程中游离脱落酸(F-ABA)含量逐渐下降,GAs含量不断上升。经高温(23℃)层积及种子淋洗处理,均能降低F-ABA的水平,但GAs含量并未上升,且束缚态脱落酸(B-ABA)含量的变化亦有别于低温层积处理。种子休眠仅被低温层积所解除。通过对种子施用标准的ABA、GAs和种子粗提物的处理,进一步验证了桃种子休眠和萌发调控的促-抑物平衡假说。 相似文献
995.
996.
997.
Treatment of one-day old yolksac larvae of tilapia (Oreochromis mossambicus) by immersion in 0.05 ppm T4 or 0.01 ppm T3 significantly accelerated the differentiation and growth of all the fins, particularly pectoral and tail fins. Both the treatments also significantly accelerated yolk absorption and transition to free-swimming activity in the larvae. The treatments also significantly accelerated the growth of the larvae, with T3 at 0.01 ppm having a greater effect than T4 at 0.05 ppm. The yolk conversion efficiency was found not to be significantly affected by the hormone treatments but the treated larvae exhibited an increased heart beat, suggesting metabolic stimulation by the hormones.On the other hand, yolk absorption and free-swimming activity were significantly delayed in tilapia larvae immersed in 25 ppm solution of an antithyroid drug, phenylthiocarbamide (PTC). PTC also retarded the growth of the larvae. T4 (0.05 and 0.10 ppm) or T3 (0.01 and 0.02 ppm) therapy removed the PTC-inhibition,albeit not completely, suggesting that thyroid hormones are involved in the larval growth and development of tilapia. 相似文献
998.
Costadinos C. Mylonas Craig V. Sullivan Jeffrey M. Hinshaw 《Fish physiology and biochemistry》1994,13(6):485-493
Gravid brown trout (Salmo trutta) females were injected with various doses of a synthetic gonadotropin-releasing hormone analog (GnRHa), given with or without
an injection of triiodothyronine (T3), in order to investigate the potential of T3 (a) to enhance the stimulatory effect of GnRHa on ovulation, and (b) to enhance the growth and survival of the produced progeny.
From the time the hormonal treatments were initiated until ovulation was detected 5–38 days later, endogenous plasma T3 levels increased from an average of 3.6 to 11.6 ng ml−1. Injection with 20 mg T3 kg−1 body weight, further elevated plasma T3 levels at ovulation (16.0 ng ml−1. Mean time to ovulation was reduced significantly in fish injected with 10 μg kg−1 of GnRHa, whereas treatment with lower doses was ineffective. Injection with T3 did not enhance the ovulatory response of brown trout to GnRHa. Unfertilized eggs obtained from T3-injected females had a higher T3 content, suggesting a transfer of T3 from the maternal circulation into the oocytes. Maternal T3 injection had no effect on egg fertilization rates, embryo survival to eyeing and hatching, or the prevalence of abnormal
larvae at the time of hatching. Length and weight gain of the progeny during yolk absorption was also not influenced by maternal
T3 treatment. At the completion of yolk-sac absorption, progeny from females injected with T3 had a higher prevalence of skeletal abnormalities than controls. The results suggest that in teleosts like brown trout, which
have high endogenous circulating T3 levels, treatment of females with T3 does not enhance responsiveness to GnRHa and it has the potential for deleterious effects on their offspring. 相似文献
999.
Whole-animal thyroxine (T4) and 3,5,3′-triiodothyronine (T3) levels were measured in larval and juvenile striped bass, Morone saxatilis, reared for 10 days at one of three levels of salinity (equivalent to fresh water (FW), one-third seawater (1/3 SW), and
seawater (SW) and two temperatures (15°C and 20°C). The striped bass were pre-metamorphic larvae, metamorphic larvae or juveniles.
The short-term effects of seawater on plasma T4 levels of juvenile striped bass were also measured. Higher salinities increased T4 levels in premetamorphic larvae. In metamorphic larvae, SW and 1/3 SW increased T4 levels and SW increased T3 levels at 20°C. This response was eliminated in those at 15°C. Whole-animal thyroid hormone content was unaffected by salinity
or temperature in juvenile striped bass, although significant fluctuations in plasma T4 levels occurred in those transferred to 1/3 SW and SW. The thyroid axis of striped bass responds to salinity and temperature
as early as in the pre-metamorphic stage. Thyroid hormones may mediate the beneficial effects of salinity on larval striped
bass growth and survival. 相似文献
1000.
Ángel García-López Emilio Pascual Carmen Sarasquete Gonzalo Martínez-Rodríguez 《Aquaculture (Amsterdam, Netherlands)》2006,261(2):789-798
A major problem in the development of Senegalese sole Solea senegalensis intensive culture is the poor control on reproduction, in part due to the lack of knowledge on the precise role of photoperiod and temperature. Thus, gonadal maturation was evaluated by assessing the sequential changes in plasma levels of 17β-estradiol (E2), 11-ketotestosterone (11-KT), and testosterone (T) in both female and male cultured Senegalese sole (F1 generation) exposed to various combinations of constant or naturally-fluctuating daylength and water temperature. Under natural photoperiod (NP; 36° N), exposure to constant temperature (t0; 18-20 °C) disrupted gonadal development, as indicated by a lower incidence (in comparison with naturally-fluctuating water temperature; 14-24 °C) of females at advanced maturation (from February to April: 12 vs. 33%) and running males (from February to May: 46% vs. 57%), and the reduced mean (± S.E.M.) sex steroid plasma levels (female peak E2 levels: 2.9 ± 0.28 vs. 1.8 ± 0.3 ng ml− 1; male peak T levels: 1.5 ± 0.14 vs. 0.9 ± 0.06 ng ml− 1). Therefore, the onset and progression of gonadal development in this species seem to be strongly (“proximally”) influenced by fluctuating water temperature. When compared to NP and t0, exposure to continuous light (LL) under t0 significantly reduced steroid production (female peak E2 levels: 1.8 ± 0.28 vs. 0.5 ± 0.05 ng ml− 1; male peak 11-KT levels: 9.4 ± 1.06 vs. 5.4 ± 1.33 ng ml− 1) and subsequently gonadal development (lower proportions of females at intermediate [46 vs. 6%] and advanced maturation [12 vs. 0%] from February to April and of RM [46 vs. 33%] from February to May). Thus, the seasonal changes of daylength would be crucial for normal gonadal development, being its cueing effects of higher magnitude than those of water temperature. The present report constitutes the first systematic study focused on the environmental control of reproductive events in Senegalese sole. 相似文献