| 词汇 | pericarp |
| 释义 | pericarp noun[ Cusually singular ] biology specializeduk /ˈper.ɪ.kɑːp/ us /ˈper.ɪ.kɑːrp/ the layer that develops from the ovary wall around the seed of a plant after it is fertilized and forms the skin and flesh of the fruit果皮（植物种子授精后沿其卵巢壁生成的一层，形成果子的皮和肉） 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 Examples of pericarppericarp The pericarp appears to form the main natural barrier to desiccation under both natural and artificial conditions of seed storage. The seeds are surrounded by the pericarp and sepals and do not become dormant. That is obvious, considering the high overlap index of their diet in fruit sizes and vegetable forms eaten (flowers, seeds, pericarps, entire fruits). There is no doubt that the presence of a fleshy pericarp is inhibitory to seed germination in some plants. One possible factor is the integrity of the pericarp, which acts as a screen against pathogenic infection and also plays an important role in osmoregulation. However, if the autumn-winter temperature is low and the soil is damp, the pericarp should afford efficient protection against water loss. After removal of the pericarp and testa, 20 seeds from each of the pretreatments, dried as well as undried, were ground in liquid nitrogen. Subsequently, the part of the pericarp covering the embryo was removed and the embryo was gently detached from the adjacent tissue using a dissecting needle. The tightly woven cell layers of the pericarp are also barriers to gases. Increases in embryo osmotic potential and in the turgor yield thresholds of both the radicle and the endosperm/pericarp envelope contributed to this change. This procedure was necessary in order to moisten the pericarp and endosperm before excision. The endosperm and pericarp consist of non-living tissue and leakage from these tissues is not likely to be influenced by ageing. The pericarp surface corresponding to the cupule is rough textured, grey and increasingly thickened from the edges to the centre. A marked reduction in the mean rate of water loss was recorded for intact acorns compared with those from which the pericarp had been removed. This may be at least partly explained by differences in leakage from the pericarps. 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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