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1.
Temperature dependencies of sprouting and germination were compared for subterranean perennating organs and seeds of ten closely
related species of the genusDioscorea (Dioscoreaceae), a group of monocotyledonous summer perennials which are distributed from the tropics to the subarctic. The
species used wereD. nipponica Makino,D. tokoro Makino,D. japonica Thunb.,D. tenuipes Franch. et Savat.,D. septemloba Thunb.,D. quinqueloba Thunb.,D. izuensis Akahori,D. bulbifera L. f.spontanea (Makino) Makino et Nemoto,D. pentaphylla. L. andD. alata L.; they are distributed from cold northern areas to warmer southern areas approximately in this order in and around Japan.
Bulbil sprouting was also studied in those forming bulbils.
Subterranean organs of the tropical species sprouted faster without any prior temperature treatment, whereas those of species
from the more northern areas sprouted after prechilling. Northern species required longer, periods of prechilling for sprouting.
On the other hand, with seeds or bulbils, the southern species required longer periods of prior temperature treatment for
dormancy breaking. This difference in the length of dormant periods between seeds or bulbils and subterranean organs among
the ten species may be related to their size and position of shedding; seeds or bulbils are small and are shed on the ground
surface, whereas subterranean organs are large and are located below the surface.
It is important to determine in other perennials whether the above relation between dormant features of seeds or bulbils and
subterranean organs are common properties or not. 相似文献
2.
Effects of GA3 and CCC application on the sprouting of bulbilsor subterranean dormant organs of 10 species in the genus Dioscoreawere observed. Although the efficiency of both chemicals differedby species, in general GA3 inhibited and CCC promoted the sproutingof the above dormant organs. In some species, however, dilutedGA3 (0.0030.3 µM) has a promotive and diluted CCC(330 µM) has an inhibitive effect on sprouting. Effects of GA3 application on shoot elongation were tested onsprouted bulbils. GA3 promoted elongation when applied directlyto the shoots and inhibited it when applied to the bulbous parts. These results suggest that GA activates two opposing reactionssprouting-promotingand sprouting-inhibitingin these organs. The complicatedrelation between GA3 or CCC concentrations and sprouting wereexplainable by assuming that the two counteractive reactionswere activated by GA in different degrees.
1 Present address: Department of Biology, Faculty of Science,Yamagata University, Yamagata 990, Japan. (Received June 21, 1976; ) 相似文献
3.
Dormancy in Dioscorea: Gibberellin-Induced Inhibition or Promotion in Seed Germination of D. tokoro and D. tenuipes in Relation to Light Quality
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Effects of light and gibberellic acid (GA3) application on the germination of Dioscorea tokoro Makino and Dioscorea tenuipes Franch. et Savat. were observed. For complete germination, seeds of both species required prechilling in moist condition before incubation at a higher temperature. Red light irradiation during the incubation after the prechilling promoted germination; blue, green, or far red light markedly inhibited the germination of both species. 相似文献
4.
An antiserum against gibberellin A4 (GA4) raised in rabbits and its partially purified antibodies were used to develop radioimmunoassay (RIA) and indirect enzyme-linked immunosorbent assays (ELISAs) for GA4. Of three immunoassays tested, an ELISA based on the NAD-dependent redox cycle (enzyme-amplified ELISA) had highest sensitivity. Levels of methylated GA4 detected by this most sensitive method ranged from 0.1 fmol/assay (3.5 fg/assay) to 0.1 pmol/assay (3.5 pg/assay) suggesting applicability of this method to the detection of gibberellins in purified plant extracts. 相似文献
5.
The temperature dependence of seed germination and seedling growth was analyzed in Dioscorea tokoro, an East Asian summer-green perennial. Seeds were able to germinate fully only at 11°–20°C. At around 17°–20°C the first
leaf petiole of the seedling elongated and quickly set the first leaf blade at a position enabling photosynthesis. At temperatures
higher than 20°C petiole elongation was retarded, and seedlings formed a rhizome and established as a perennial. The rhizome
size increased with temperature up to 29°C. Thus, during growth immediately after germination, temperature appears to be a
key factor in determining whether the plant establishes as a perennial or grows rapidly without rhizome thickening.
Received: April 6, 2001 / Accepted: September 14, 2001 相似文献
6.
Nobuo Okagami Noriaki Tanno Massashi Kawai Akira Hiratsuka Ken-ichi Satoh Keisuke Terui 《Plant Growth Regulation》1997,22(2):137-140
Effects of the application of gibberellin A3 (GA3) on sprouting of rhizomes and germination of seeds were tested in five species of the genus Dioscorea which are considered to be Tertiary relicts growing disjunctively in the Appalachians, the Balkans, and the Caucasus. Applied GA3 at higher than 1 micro;M markedly inhibited sprouting of rhizomes of all species. However, inhibition of seed germination of these species by GA3 application was not observed. It is hypothesized that before disjunction in the Tertiary period GA-induced dormancy probably prevailed in rhizomes of all members of the genus Dioscorea. 相似文献
7.
Changes in the amount of growth inhibitors by gibberellin (GA)treatment in tubers of Begonia evaniana was studied. Acidic,neutral and basic ethyl acetate-soluble and n-butanol-solublegrowth inhibitors increased with GA treatment and also withthe progress of natural dormancy. These inhibitors suppressedthe sprouting of nondormant aerial tubers. The increase of neutralethyl acetate-soluble inhibitors in the GA-treated tubers wassuppressed by incubation in low-O2 atmosphere. In early dormantstage tubers, the inhibitor increased remarkably during incubationat 28?C in light. The aerial tubers probably enter a dormantstate when sufficient amounts of inhibitors accumulate in them. (Received February 9, 1973; ) 相似文献
8.
The effects of temperature on induction and release of high-temperatureinhibition in seed germination of Dioscorea tokoro Makino, amonocotyledonous summer perennial of the temperate zone of EastAsia, were investigated. Germination was increasingly inhibitedwith elevation of temperature over 23°C and lengtheningof its duration. The low temperature limit for germination inhibitiondecreased with lengthening of the duration of high temperature.The most sensitive phase for high temperature was 12days after the start of imbibition at 20°C. The germination inhibition by high temperature was reversedby chilling at 5°C, which is the optimum temperature forbreaking the natural dormancy (primary dormancy) of this seed.This showed that the high-temperature inhibition of germinationdoes not cause mortal damage but only secondary dormancy (induceddormancy). Seeds from a cold climate (Miyagi Pref.) responded rather quicklyto both high temperature and chilling compared to seeds froma warm climate (Kagoshima Pref.). The responsiveness to hightemperature and chilling of D. tokoro seed may affect the germinationtime under natural conditions. (Received October 22, 1982; Accepted January 14, 1983) 相似文献
9.
Effects of the application of gibberellic acid on sprouting of tubers or rhizomes were tested in seven species of the genus Dioscorea that are native to the temperate regions of East Asia. The lowest concentrations for significant inhibition of sprouting in these species varied from 0.1–1 µM Application of gibberellic acid at 100 µM inhibited sprouting for more than 500 days at 20 °C. Some responses to the application of gibberellic acid differed between species and between sections of the genus. In D. japonica, the application of gibberellic acid inhibited sprouting of tubers and bulbils while it promoted seed germination. 相似文献
10.
Osmorhiza aristata is an herbaceous perennial that grows primarily in Japan, through southern China, to the Himalayas. It closely resembles the eastern North American species O. claytonii and O. longistylis, and, together, the three species are an example of the well-known North American-Asian pattern of disjunction. Requirements for dormancy break and embryo growth were determined for seeds of O. aristata collected in Japan during the summers of 1998-2000. Embryos in fresh seeds were ca. 0.5 mm long, and they had to grow to 9 mm before the radicle emerged from the mericarp. Embryo growth and germination occurred during cold stratification at 5°C, the optimum temperature for germination. Gibberellic acid did not substitute for cold stratification. Thus, O. aristata seeds have deep complex morphophysiological dormancy (MPD). The type of MPD in O. aristata is similar to that in two western North American congeners but different from that in eastern North American congeners (nondeep complex MPD). Mapping the types of MPD onto a phylogeny of the genus suggests that nondeep complex MPD is derived from deep complex MPD. Although eastern North American-Asian disjuncts often exhibit morphological stasis, the taxa may differ greatly in physiological traits, such as seed dormancy. 相似文献