PHYSIOLOGICAL DETERMINANTS OF GROWTH-RATE IN RESPONSE TO PHOSPHORUS SUPPLY IN WILD AND CULTIVATED HORDEUM SPECIES
PHYSIOLOGICAL DETERMINANTS OF GROWTH-RATE IN RESPONSE TO PHOSPHORUS SUPPLY IN WILD AND CULTIVATED HORDEUM SPECIES
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DOI：
10.1007/bf00378245
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发表时间：
1989-01-01
期刊：
影响因子：
2.7
通讯作者：
EVANS, LT
中科院分区：
文献类型：
--
作者：
CHAPIN, FS;GROVES, RH;EVANS, LT
在良好的营养条件下，大麦草（Hordeum leporinummanh）的产量。青稞（glaucum）的相对生长率（RGR）高于栽培大麦（H. vulgare）及其野生祖先（H. spontaneum）。无论是种内还是种间，RGR与采集点土壤肥力的推定水平均无正相关关系。相比于作物或杂草，低磷供应对RGR的降低更强烈，这表明选择在肥沃土壤中生长的品种并没有降低它们在低磷条件下有效生长的潜力。种子和胚质量比RGR对植株大小的影响更大。不同品种间植株大小的相对差异随着时间的推移而减小，主要表现为：(1)小种子品种的RGR较高，而(2)大种子品种的RGR随时间而减小。绝对生长率与叶面积正相关，与单位叶面积光合速率负相关。在营养条件较好的情况下，最大光合速率与叶片长度呈负相关，因此杂草的最大光合速率高于作物或祖先材料。不同物种对磷的吸收电位差异不一致，但对磷胁迫的响应普遍增加。品种产生少数高分蘖，而杂草和祖先产生许多小分蘖。该品种生殖分蘖比例较大，生物量分配给籽粒的比例较大，籽粒产量较大。相比之下，这种杂草的种子成熟得更快，产生了更多的繁殖分蘖，每辆车和每株植物的产量都比该品种高。本研究得出两个主要结论：(1)低RGR不是一年生hordeum种对低磷供应的适应。(2)在营养条件较好的情况下，种子大小是不同品种间早期植株大小的主要决定因素。但是，种子大小大，由于植株大小与RGR成反比关系，间接导致RGR低；由于叶片大小与光合作用成反比关系，间接导致光合速率低。
Under favorable nutrition, accessions of the weedy barleygrass (Hordeum leporinumandH. glaucum) had a higher relative growth rate (RGR) than did accessions of cultivated barley (H. vulgare) or its wild progenitor (H. spontaneum). RGR wasnotpositively correlated with the presumed level of soil fertility at the collection site of an accession either within or among species. RGR was reduced more strongly by low-P supply in the progenitor than in the crop or weed, indicating that selection of cultivars to grow in fertile soils had not reduced their potential to grow effectively under low-P conditions. Seed and embryo masses were more important than RGR in determining plant size. Relative differences among assessions in plant size declined with time, because (1) accessions with small seeds had a higher RGR, and (2) RGR of large-seeded accessions declined with time. Absolute growth rate correlated positively with leaf area and negatively with photosynthetic rate per unit leaf area. Under favorable nutrition, maximum photosynthetic rate correlated negatively with leaf length and therefore was higher in the weeds than in the crop or progenitor accessions. P absorption potential did not differ consistently among species but generally increased in response to P stress. Cultivars produced a few tall tillers, whereas weeds and progenitors produced many small tillers. The cultivar had a larger proportion of reproductive tillers, allocated a larger proportion of biomass to grain, and produced larger grains than did the weedy accession. By contrast, the weed began maturing seeds sooner, produced more reproductive tillers, and produced more grains per car and per plant than did the cultivar. The study suggests two major conclusions: (1) A low RGR isnotan adaptation to low P supply in annualHordeumspecies. (2) Seed size is the major determinant of early plant size between accessions in theseHordeumspecies under favorable nutrition. However, large seed size indirectly results in a low RGR because of the inverse relationship between plant size and RGR and results in a low photosynthetic rate because of the inverse relationship between leaf size and photosynthesis.