有些植物（如松杉、桉树、某些草）的种子要被火烧过才发芽，火对它们是朋友吗？
Some plants' seeds (pines, eucalypts, some grasses) only sprout after fire—is fire a friend to them?
对这类“耐火/依赖火”植物，火烧会烤裂种皮、溶出抑制发芽的物质，并把竞争者烧光、把灰分（钾磷）当肥料。所以它们演化出“趁火重生”的策略，火是更新的信号而非灾难。
For fire-dependent species, heat cracks seed coats, leaches germination inhibitors, clears competitors and returns ash (potassium, phosphorus) as fertilizer. They evolved to “rebloom through fire”—fire is a regeneration signal, not disaster.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Raven 等,《Biology of Plants》第8版,W. H. Freeman,2013
P. H. Raven et al., Biology of Plants, 8th ed., W. H. Freeman, 2013
独立核验依据 · Independent verification: 核验依据 2 OPENLIBRARY 标识 /works/OL16626503W：Biology of plants（按标题+
#火 #种子 #更新
许多温带木本植物的种子为何要经历一个冬季的低温才能顺利发芽?
Why do seeds of many temperate woody plants need a winter of chilling before they germinate properly?
低温层积期间,胚内的脱落酸被逐步代谢,促进赤霉素合成的基因随之上调,萌发的生理刹车就此松开。这套计时机制防止种子在初秋短暂回暖时提前出苗而遭冻害。只有完整经历冬季低温的个体才会在春季同步萌发,这对幼苗存活率至关重要。
During chilling, abscisic acid in the embryo is progressively catabolized while genes for gibberellin biosynthesis are upregulated, releasing the physiological brake on germination. This timing device stops seedlings from emerging during warm spells in early autumn, when frost would kill them. Only seeds that experience the full winter chill germinate together in spring, which strongly shapes seedling survival.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Finch-Savage 与 Leubner-Metzger,《Seed dormancy and the control of germination》,New Phytologist,2006 (DOI: 10.1111/j.1469-8137.2006.01787.x)
Finch-Savage & Leubner-Metzger, 'Seed dormancy and the control of germination', New Phytologist, 2006, DOI: 10.1111/j.1469-8137.2006.01787.x
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1111/j.1469-8137.2006.01787.x
#种子与萌发 #低温层积
种子为什么有的晒干能存几十年,有的放几个月就发不了芽?
Why can some seeds survive decades after drying while others lose viability within months?
按贮藏行为种子分为正统型与顽拗型:正统型种子(如禾谷类)成熟时脱水到很低含水量,代谢近乎停滞,低温干燥下可存活数十年;顽拗型种子(如芒果、橡胶)不耐脱水,离体后仍保持高含水量和活跃呼吸,很快丧失活力。这种差异源于膜脂组成和保护性蛋白(如LEA蛋白)积累量的不同。
Seeds fall into orthodox and recalcitrant storage classes: orthodox seeds (cereals, for example) dehydrate to very low moisture at maturity, nearly halting metabolism so they last decades when cold and dry. Recalcitrant seeds (mango or rubber) tolerate no drying; they keep high water content and active respiration after shedding and lose viability within months. The difference traces to membrane lipid composition and how much protective protein such as LEA proteins accumulates.
难度 进阶 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Bewley & Black,《种子的发育与萌发生理学》,普莱南出版社;国际植物遗传资源委员会种子贮藏手册
J. D. Bewley & M. Black, Physiology of Development and Germination, Plenum Press; IBPGR seed storage handbook
#种子休眠 #脱水耐受