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玉米opaque2(o2)是胚乳发育的核心调控基因,对子粒发育至关重要。基于9组糯玉米o2近等基因系(o2-NILs)及对应轮回亲本,对鲜食期和成熟期子粒的种皮厚度、总淀粉含量、可溶性糖含量等性状进行分析。结果表明,黄糯2/o2o2和中63-2/o2o2鲜食期子粒的食味品质性状均有提高,其他o2-NILs子粒品质变化不一。鲜食期o2突变对种皮厚度影响较大,但与成熟期无直接相关性。o2突变使玉米子粒赖氨酸含量增加,营养价值提高,但多数近等基因系成熟期淀粉含量和百粒重降低,仅糯2/o2o2、淀粉含量和百粒重均不受影响。糯2/o2o2、SY1-2/o2o2、赵OP-6/o2o2中27 KD γ-zein表达量显著增加、子粒饱满度与轮回亲本相近,但均表现为粉质胚乳,因此认为,优质蛋白糯玉米硬质胚乳的恢复需多个o2胚乳修饰基因协同作用。 相似文献
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R. A. Sutherland J. O. Bussen D. L. Plondke B. M. Evans A. D. Ziegler 《Land Degradation \u0026amp; Development》2001,12(1):71-86
Recreational activities can have significant impacts on geomorphic and hydrologic processes in drainage basins, often out of proportion to their areal extent. With increased stress on hiking trails nationwide, there is a need to characterize the impacts of human trampling on soil properties. We examine an 810 m segment of Hawai'iloa Ridge Trail (O'ahu, Hawai'i, USA). Soil compaction and surface erosion on moderate to steeply sloping sites have degraded the trail environment. Bulk density, penetration resistance, and vane shear strength were significantly higher on the trail than in adjacent undisturbed areas, with median differences ranging from 29 to 120 per cent. With compaction and exposure of subsoil on the trail, void ratio, air‐filled porosity, saturated hydraulic conductivity, effective and preferential porosity were significantly lower, with relative change values ranging from 23–93 per cent. No significant changes were noted in meso‐ or micro‐porosity, but macropores with a radius of >110 μm decreased significantly by 58 per cent for on‐trail locations. This comprehensive dataset indicates that hiking stress is deleterious to the soil–hydrologic system. Data point to a trail system that would be dominated by Hortonian overland flow and this was supported by field evidence during a storm event. Increased runoff has incised rills on some trail segments and there is evidence that run‐on to adjacent side slopes has lead to accelerated erosion. Management on most trails in Hawai'i, including the one studied, is limited, but from our data it is apparent that on‐trail sites directly influenced by an overhanging canopy of rapidly growing (aggressive) exotics were least impacted due to increased organic contributions to the surface and root network development. These data will allow land managers to more effectively address the potential geomorphic and hydrologic impacts of recreational land use. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献