硼对植物生殖器官建成的作用

实验以黄瓜植物为材料，研究了硼在个体水平上和器官水平上对植物生殖器官建成的作用，并用放射性同位素示踪法研究了硼对植物生殖器官的作用同植物体内糖运输的关系。结果表明，在个体水平上，缺硼使植物体上雄花和雌花数目都减少，但缺硼对雌花形成和雄花形成的影响并不相同，缺硼使植物体上形成较多的雄花，较少的雌花。在器官水平上，硼的作用同它的浓度有关，在某一浓度范围内，缺硼不利于黄瓜花蕾发育成雌花-也不利于雄花花药的发育;硼浓度的升高有利于花蕾发育成雌花，也有利于发育成雄花的花蕾花药的发育。较高浓度的硼则明显使黄瓜花蕾不易发育成雌花，但有利于发育成雄花的花蕾花药的发育。在个体水平上，缺硼对生殖器官建成的作用同花蕾组织中可溶性糖的缺乏有关，这可能是由于缺硼抑制了茎等输导组织的糖吸收活动而使叶片光合作用所合成的糖不易运到花蕾中的原因。

Practicing coastal seascape ecology

Landscape ecology concepts developed from terrestrial systems have recently emerged as theoretical and analytical frameworks that are equally useful for evaluating the ecological consequences of spatial patterns and structural changes in the submerged landscapes of coastal ecosystems. The benefits of applying a spatially-explicit perspective to resource management and restoration planning in the coastal zone are rapidly becoming apparent. This Theme Section on the application of landscape ecology to the estuarine and coastal environment emerged from a special symposium at the Coastal and Estuarine Research Federation (CERF) 20th Biennial Conference (Estuaries and Coasts in a Changing World) held in Portland, Oregon, USA, in November 2009. The 7 contributions in this Theme Section collectively provide substantial insights into the current status and application of the landscape approach in shallow marine environments, and identify significant knowledge gaps, as well as potential directions for the future advancement of ‘seascape ecology’.

Geochemical evidence for enhanced upwelling and organic productivity during the late Quaternary on the continental margin of northern California

EXTRACT (SEE PDF FOR FULL ABSTRACT): Laminated sediments are preserved in upper Pleistocene sections of cores collected on the continental slope at water depths within the present oxygen-minimum zone from at least as far north as the Klamath River and as far south as Point Sur. Comparison of sediment components in the laminae with those delivered to sediment traps as pelagic marine "snow" show the dark/light lamination couplets are indeed annual (varves). ... The presence of carbon-, sulfur-, and metal-rich sediments, as well as lack of bioturbation, all support the theory that the oxygen-minimum zone in the northeastern Pacific Ocean was more intense - in fact, anoxic - during the late Pleistocene in response to greater coastal upwelling and higher organic productivity.

The Los Alamos General Circulation Model hydrologic cycle

As the global population has increased, so have human influences on the global environment. ... How can we better understand and predict these natural and potential anthropogenic variations? One way is to develop a model that can accurately describe all the components of the hydrologic cycle, rather than just the end result variables such as precipitation and soil moisture. If we can predict and simulate variations in evaporation and moisture convergence, as well as precipitation, then we will have greater confidence in our ability to at least model precipitation variations. Therefore, we describe here just how well we can model relevant aspects of the global hydrologic cycle. In particular, we determine how well we can model the annual and seasonal mean global precipitation, evaporation, and atmospheric water vapor transport.

Application of remote sensing to marine fisheries: alternative approaches

A discussion is presented on the applications of remote sensing to fisheries. The measurement of temperature, wind stress, and ocean colour using remote sensing techniques is considered.