| 词汇 | cotyledon |
| 释义 | cotyledon noun[ C ] biology specializeduk /ˌkɒt.ɪˈliː.dən/ us /ˌkɑː.t̬əˈliː.dən/ a type of leaf that is part of the developing plant inside a seed and either stores food or grows from the seed to produce food子叶（植物种子胚的叶片，可储藏营养或制造营养） Parts of plants axil bark bilobed blade bulb caning cascara sagrada corolla endodermis inflorescence knot pistil rooty rosella seed coat seed pod sessile sting taproot tubule A few plants that bear cones like the pines have several cotyledons. After roasting, the shell is brittle and quite free from the cotyledons or kernel. Skin the peas in question, separate the cotyledons, and break them up as may be necessary. The ants enjoyed the sprouting cotyledons of all but one. Within the cotyledon will be found a little growing shoot pointed toward the top of the kernel. cotyledon | American Dictionarycotyledon noun[ C ] us/ˌkɑt·əlˈi·dən/ biology a type of leaf that is part of the developing plant inside a seed and that either stores food or grows from the seed to produce food Examples of cotyledoncotyledon In four instances, the testa was removed from one end of the seed and the fleshy cotyledons eaten from the centre. Although cell size in the cotyledons was not significantly lower in the spaceflight material than in the ground control, the cotyledons contained substantially fewer cells. During the period between radicle emergence and hook formation, relations between cotyledon length and the time from visible germination were linear. Solubility of axis cell walls differed from solubility of cotyledon cell walls. Removal of the cotyledons strongly diminished enzymatic activity in the embryonic axis. There is a concomitant increase in protein reserves which progresses in the same wave-like pattern outward from the cotyledon. A seedling was considered fully established when two leaves appeared in addition to the green cotyledons. Seedlings with emerged cotyledons were monitored and removed each time from the pots. In cotyledons, methyl esterification ranged from 25 to 40 mole% and was 31 mole% after desiccation. To facilitate equilibration, seed cotyledons were chopped into c. 1 mm3 pieces. Prior to acquisition of desiccation tolerance, seeds produced seedlings with either shortened radicle tips, unexpanded hypocotyls or folded cotyledons. The seeds are flattened and seedlings are phaneroepigeal with leafy cotyledons. Diaspores are gravity dispersed and the seed coat rapidly decays, exposing cotyledons to the immediate environment prior to germination. Rather, a stimulus released from the cotyledon is more likely to induce the major cell wall degrading enzyme, endo- mannanase, within the endosperm itself. Then embryos were isolated from the endosperm and pericarp by gently pressing the seed at the cotyledon end. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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