基于多源数据的城市形态成熟度评价指征——以上海新老城区为例

In China,in recent years it has become a prevailing trend to promote the spatial maturity and high-quality transformation of new towns,yet there are few quantitative methods to evaluate their urban morphological maturity.From the perspective of quantitative urban morphology,this paper integrates street view data and cutting-edge analytical techniques into classic urban morphological study and develops a quantitative index for evalu-ating urban morphological maturity that fits Chinese cities by adjusting the indicators in line with the unique characteristics of the built environment ofChinese cities.Focusing on five new towns,as well as a historic area,of Shanghai,the paper evaluates their urban morphological maturity with this quantitative index and verifies its validity by comparing the evaluation result with that of expert consensus.It then proposes some design guidelines that may provide robust support for the regeneration of these new towns.Given its reliance on the multi-source data of open access and ready avail-ability,this index holds promise for evaluating the urban morphological maturity of other new towns,to provide support for urban form improvement frombothholisticanddetailed perspectives.

Use of genotype-environment interactions to elucidate the pattern of maize root plasticity to nitrogen deficiency

Maize（Zea mays L.） root morphology exhibits a high degree of phenotypic plasticity to nitrogen（N） de ficiency,but the underlying genetic architecture remains to be investigated Using an advanced BC_4F_3 population,we investigated the root growth plasticity under two contrasted N levels and identi fied the quantitative trait loci（QTLs） with QTL-environment（Q×E）interaction effects. Principal components analysis（PCA） on changes of root traits to N de ficiency（D LN-HN） showed that root length and biomass contributed for 45.8% in the same magnitude and direction on the first PC,while root traits scattered highly on PC_2 and PC_3. Hierarchical cluster analysis on traits for D LN-HN further assigned the BC_4F_3 lines into six groups,in which the special phenotypic responses to N de ficiency was presented These results revealed the complicated root plasticity of maize in response to N de ficiency that can be caused by genotype environment（G×E） interactions. Furthermore,QTL mapping using a multi-environment analysis identi fied 35 QTLs for root traits. Nine of these QTLs exhibited signi ficant Q×E interaction effects. Taken together,our findings contribute to understanding the phenotypic and genotypic pattern of root plasticity to N de ficiency,which will be useful for developing maize tolerance cultivars to N de ficiency.