外源激素在西洋参种胚后熟中的作用研究

西洋参(Panax Quinquefolium L.)种胚需经形态后熟和生理后熟后才能萌发.经过激素(GA100ppm+KT50ppm+BA20ppm)处理的西洋参种子,在后熟过程中鲜重增加,β—淀粉酶活性增强,过氧化物酶活性保持较高水平.在生理后熟期,可溶性蛋白量逐渐增多.激素处理加速了胚体内物质的分解和合成,促使胚迅速发育和分化,缩短了种胚完成形态和生理后熟的时间,使种子提早一年萌发.     

A comparison of two large-scale seed priming techniques

Leek seed lots of high (91%) and low (82%) viability were primed in aerated polyethylene glycol (PEG) solutions in Bubble-columns and by a non-osmotic priming technique in both 1987 and 1988 and the seeds were then sown in the field. Both methods of priming established a similar seed moisture content during treatment and, in the laboratory, produced seeds with more rapid and uniform germination than untreated seeds, with a greater advantage for Drum compared with Bubble-column priming in PEG. In the field, both priming techniques gave seedling emergence responses similar to those from priming in PEG by the laboratory-scale technique on filter paper. Both large-scale priming methods gave earlier and more uniform emergence than untreated seeds and gave similar or slightly higher levels of seedling emergence, except on one sowing occasion when seeds were stored before sowing followed by sowing into a drying seedbed.     

After-ripening and phytochrome action in seeds of dormant lines of wild oat (Avena fatua)

The effects of a short exposure to red, far-red or alternate red/far-red light on the germination of seeds after-ripened for different periods of time were studied in dormant lines of wild oat ( Avena fatua L.). Three stages were distinguishable in the after-ripening period in the response of germination to light. Seeds stayed dormant and showed no response to light during stage I. Phytochrome-mediated germination was observed in seeds during stage II. The phytochrome action disappeared during stage III, i.e. seeds fully germinated following treatments of all light qualities. When the seeds were imbibed in polyethylene glycol solutions, dark germination was reduced and phytochrome again had an effect, which suggested the involvement of phytochrome in water uptake of the seed.     

Polyribosomes and protein synthesis in after-ripening pear seeds

Polyribosomes have been isolated from pear seeds which show a capacity for in vitro protein synthesis. Translational capacity increased during stratification with a peak after 13 days of stratification. This increase was greatly diminished in seeds which were incubated at 25°C (“warm stratification”). The peak in protein synthetic activity coincides with the period of stratification required for normal development of excised embryos.     

Successful seed germination of the nickel hyperaccumulator Stackhousia tryonii

* BACKGROUND AND AIMS: Stackhousia tryonii, a rare nickel hyperaccumulating herb, is endemic to ultramafic (serpentine) soils of central Queensland, Australia. The effects of eight dormancy-relieving treatments on germination of stored seeds of Stackhousia tryonii were investigated under controlled light and temperature conditions. * METHODS: The treatments were: untreated (control i), leached and dehydrated (primed control ii), treating with gibberellic acid (150 and 300 microM), smoke extract (5 and 10 %, v/v) and potassium cyanide (40 and 80 mM). * KEY RESULTS: Freshly harvested seeds did not germinate. Germination percentage increased with time of storage for up to 18 months (38.3 %). Gibberellin, smoke extract and cyanide treatments did not significantly improve germination. Light did not affect seed germination and there was no interaction between dormancy-relieving treatments and light. A significant inhibition of germination occurred in seeds treated with 5 % (but not 10 %) aqueous smoke extract. Saturated fatty acids, predominantly tridecanoic (C13:0), constituted about 90 % of the total fatty acids in the oil of freshly harvested seeds. In contrast, there was increased accumulation (>75 %) of mono-unsaturated (oleic, c18:1) and poly-unsaturated (linoleic, c18:2; linolenic, c18:3) fatty acids in the oil of stored seeds. * CONCLUSIONS: Seeds of S. tryonii require an after-ripening period for germination.     

Anatomical Studies of After-Ripening of Coptis chinensis Seed

The seeds of Coptis chinensis Franeh took 9–10 months to germinate after they were collected and buried under ground.. This is due to the fact that the embryo of Coptis chinensis was not fully developed after shedding but remained in the stage of globular or early heart-shaped embryo, and the latter of which has to pass through a rather long period before it developed into torpedo-embryo stage. Embryo completed its growth about January of the following year. The delay in seed germination is because of the embryo not being fully developed after shedding. However, the primordium of the first foliage leaf initiated early in the apical meristem of the young embryo. Perceiving the whole process of the young embryo growth, it seems possible that, if a suitable condition is envisaged to shorten the heart-shaped embryo stage, the whole germinating process of seed might be somewhat curtailed.     

Effect of Hormones on Embryo After-Ripening of Panax ginseng G. A. Mey. Seeds

Panax ginseng C. A. Mey seed has a deep dormancy for the morphologica and physiological after-ripening of embryo. This paper described the changes of some enzymic activities and of soluble-protein content during after-ripening of seeds, in the first stage of morphological after-development the activities of amylase, peroxidase and catalase increased gradually, whereas the soluble-protein content decresed rapidly. A high level of enzymatic activities and increasing protein content were also observed, indicating vigorous metabolism in physiological after-ripening of seeds. Hormone treatment increased the activities of the above-mentional enzymes, promoted the development and differentiation of embryo, causing the time of seeds germination one year earlier than that of untreated ones.     

黄连种子后熟过程的解剖学研究

黄连种子采收埋土后,需要经过9—10个月才能出土萌发。这是由于黄连种子在4—5月脱落吋,胚未成长,一般尚只在球形胚或心形胚早期。后来经过较长时期心形胚阶段,才变成鱼雷形胚。大约要到翌年1月时,胚胎完全成长。所以黄连种子不易萌发是因为胚胎尚未成长。不过,黄连幼胚的胚轴上端的顶端分生组织旁第一片真叶原基则出现很早。从黄连胚胎的整个成长过程来看,如果创造某种条件设法缩短心形胚阶段,可能缩短整个种子的萌发过程。     

Factors influencing growth of embryonic axes from dormant seeds of hazel (Corylus avellana L.)

Chilling (after-ripening) of hazel seeds stimulates subsequent growth of excised embryonic axes on sucrose and leads to growth which is less susceptible to inhibition by abscisic acid. Chilling also obviates the need for inorganic salts in the culture medium. Axes from dormant seeds grow normally when only one-third of a cotyledon is left attached.Abbreviation ABA abscisic acid