Near-shore distribution of Heaviside’s (Cephalorhynchus heavisidii) and dusky dolphins (Lagenorhynchus obscurus) at the southern limit of their range in South Africa

Photo-identification surveys over three years along 390 km of coastline north of Cape Town, revealed that Heaviside’s dolphin distribution was consistent between years and higher in areas more exposed to swells and with greater long-term availability of small hake Merluccius capensis (their principal prey). Dusky dolphin sighting rates varied considerably between years, but were generally higher in areas with lower hake availability and sandier shores (mostly straighter coastline). Large groups of 50–200 dusky dolphins were only seen in St Helena Bay, the site of a wind-driven upwelling zone. Heaviside’s dolphins were found in shallower, cooler water than dusky dolphins and were more likely to be seen during brighter phases of the moon (when nocturnal light conditions may influence the vertical migration patterns of prey) and in areas of high hake abundance. Near-shore fishing activity was higher in the northern half of the study area and clustered around harbours. Set netting occurred only at Yzerfontein and St Helena Bay, but due to changes in the industry is currently thought to be a low threat to the population. Interactions between Heaviside’s and dusky dolphins were usually neutral and sympatry appears to be mediated by differences in overall range and the type and size of prey species taken.     

内蒙古大兴安岭林区森林旅游业现状与发展对策

旅游业是前景广阔的"朝阳产业",森林旅游业是其中的重要组成部分。同时,森林旅游业也是未来林业发展的支柱产业之一。内蒙古大兴安岭林区风光秀丽,山峦逶迤,河流密布,林海茫茫,是不可多得的森林旅游胜地。因此,加强内蒙古大兴安岭林区森林旅游业的开发势在必行。     

论河南省公路绿化植物选择

河南省境内交通发达、公路纵横,其公路绿化得天独厚、大有可为。河南省公路绿化植物的选择,应遵循交通安全、生态优先、因地制宜、多重效益兼顾、生物多样性几项原则,并且依中央隔离绿化带、快慢道隔离绿化带、路肩绿化带、边坡绿化带、边沟绿化带、主绿化带这些不同地段的立地条件和绿化要求,来选择相应的植物种类。     

Changes in NMR Relaxation of Rice Grains,Kernel Quality and Physicochemical Properties in Response to a High Temperature after Flowering in Heat-Tolerant and Heat-Sensitive Rice Cultivars

Abstract

Rice productivity is related to the ability of plants to adapt to heat stress. The heat-tolerant cultivars ‘Nikomaru’ and ‘Chikushi 64’ and heat-sensitive cultivar ‘Hinohikari’ were grown at 30ºC and 25ºC for 49 days after flowering. At 30ºC, only a few white immature kernels were produced in ‘Nikomaru’ and ‘Chikushi 64’, but about 22% of grains had immature kernels in ‘Hinohikari’. The high temperature(30ºC) caused no significant changes in grain dry weight, water content, and the NMR T₁ value during the early ripening stage in ‘Nikomaru’ and ‘Chikushi 64’. It also did not affect grain development, especially with respect to the nucellar epidermis, in ‘Nikomaru’ and ‘Chikushi 64’, but caused clear cessation of development of the nucellar epidermis at 14 days after flowering in ‘Hinohikari’. In addition, high temperature decreased the amylose content and increased hardnessvs. adhesion ratio of cooked rice in both ‘Nikomaru’ and ‘Chikushi 64’ resulting a softer, less sticky texture, but not in ‘Hinohikari’. The maximum viscosity and breakdown values were increased, and final viscosity decreased at 30ºC in all three cultivars. These results suggested that starch in the endosperm of grains changed from a fluid state to a doughy state more slowly in ‘Nikomaru’ and ‘Chikushi 64’ than in ‘Hinohikari’, in which the water content and NMR relaxation time decreased, and transported assimilates accumulated slowly during grain development.     

转变四川农业发展方式的困境与途径研究

加快农业发展方式转变是实现传统农业向现代农业转变，实现农业可持续发展能力和促进农民持续增收的关键。文章以四川省为例，分析了四川现代农业发展面临着的粮食安全与结构调整、投入不足与要素流失、劳动力富余与结构性短缺、生产发展与可持续发展等困境，认为要转变农业发展方式，必须要发展适度规模经营，加快科技创新，不断延长农业产业链和拓展农业多功能，大力发展特效效益农业，走可持续发展之路。     

盐碱胁迫对两个葡萄品种光合作用-光响应特性的影响

在3种不同盐碱胁迫:低度、中度、重度盐碱胁迫条件下,分析了葡萄品种“克瑞森”和“青提”2 a生叶片的光合作用-光响应特性、叶绿素含量及长势情况.结果表明:“克瑞森”、“青提”光合作用-光响应曲线符合非直角双曲线模型.盐碱胁迫没有降低2个葡萄品种的光合能力,而是增强其光合能力,表观量子效率AQY值的上升表明盐碱胁迫下2个葡萄品种对光的响应敏感性较强,对弱光的利用能力较高.净光合速率(Pn)、暗呼吸速率(Rd)、叶绿素含量及长势情况说明“青提”较“克瑞森”具有更强的盐碱适应性能力.同时,2种葡萄在受到盐碱胁迫后其净光合速率的降低不是由于气孔的关闭引起CO2供应不足造成的,而是受强光下光抑制的加强等非气孔限制因素的影响,包括叶肉阻力增大、羧化酶活性和RuBP再生速率降低等.     

微生物叶面肥改善龙冈茌梨果实品质的研究

以10 a生龙冈茌梨为材料,研究了不同浓度的微生物叶面肥在其不同发育时期喷施处理对其外观品质和内在品质的影响.结果表明:微生物叶面肥能显著地提高龙冈茌梨的单果重,减小果皮厚度;但是低浓度处理对其果皮色泽和光洁度、果锈数量以及口感的改善效果不明显,只有在高浓度时才稍有改善.微生物叶面肥能显著提高龙冈茌梨果实的可溶性总糖含量以及可溶性固形物含量,能显著地降低龙冈茌梨果实的可滴定酸含量和石细胞含量,但是对果实硬度的改善并不明显.综合不同浓度微生物叶面肥对龙冈茌梨果实外观品质和内在品质的影响,认为较高浓度有助于提高龙冈茌梨的品质,以1∶600处理的效果最好.     

厚皮甜瓜新品种“千玉1号”的选育

厚皮甜瓜新品种“千玉1号”是以优良高代甜瓜自交系HO13为母本和优质父本P74配制而成.该品种全生育期95 d左右,果实发育期28～30 d,果实圆球形,果面洁白透亮,不掉蒂;果肉橙红色,肉厚3.5～4 cm,干腔小,中心可溶性固形物含量16％～18％.单瓜重0.8～1.0 kg,产量4 100 kg/667m2左右.