Variation of Leaf Characteristics in Populus tomentosa Carr

An investigation was conducted to determine the extent of variations among nine provenances of Populus tomentosa Carr. in terms of leaf characteristics. A total of 263 accessions were studied under field conditions in the National Gene Bank of P. tomentosa in 2003. All of the accessions were characterized by 17 indices from 1 to 2-dimension constructions. Variance analysis of all characteristics showed that there were significant differences among the nine provenances and among individuals within each provenance. This study reveals that the evaluated germplasm appears to have a wide genetic base and high potential for further genetic improvements and it also indicates that abundant gene resources of P. tomentosa have been collected and preserved in the National Gene Bank.

Study on the Photosynthetic Characteristics in Spring Maize (Zea mays L.)of Different Quality Type

common maize synthetic rate（ Photosynthetic characteristics were probed by sweet maize, waxy maize, high starch maize and The results revealed that leaf area index （LAI）, chlorophyll a content, chlorophyll b content,photo-PR） showed single peak curve at the whole growth stage. The stages of peak were different according to different varieties. NEAUS4 had the lowest peak and while SIDAN 19 had the highest among all stages. Ratio of chlorophyll a to b was low at seedling stage, reached the peak atjointing stage and then declined. SIDAN 19 had the lower level at the last stages.

Interactive effects of elevated CO_(2)and temperature on the anatomical characteristics of leaves in eleven species

The anatomical features of leaves in 11 species of plantsgrowninatemperaturegradientandatemperature+CO_(2)gradient were studied.The palisade parenchyma thickness,the spongy parenchyma thickness and the total leaf thickness were measured and analyzed to investigate the effects of ele-vated temperature and CO_(2)on the anatomical characteristics of the leaves.Our results show that with the increase of temperature,the leaf thickness of C_(4)species increased while the leaf thickness of C_(3)species showed no constant changes.With increased CO_(2),seven out of nine C_(3)species exhibited increased total leaf thickness.In C_(4)species,leaf thickness decreased.As for the trend on the multi-grades,the plants exhibited linear or non-linear changes.With the increase of temperature or both temperature and CO_(2)for the 11 species investigated,leaf thickness varied greatly in different plants(species)and even in different branches on the same plant.These results demonstrated that the effect of increasing CO_(2)and temperature on the anatomical features of the leaves were species-specific.Since plant structures are correlated with plant functions,the changes in leaf anatomical characteristics in elevated temperature and CO_(2)may lead to functional differences.

Phenotyping of poplar seedling leaves based on a 3D visualization method

In plant research,there is a demand for non-destructive and non-invasive trait measurement methods for phenotyping that can be used to accurately analyze various aspects of plants,such as stem length,leaf area,and leaf inclination.In this study,a method for measuring the leaf geometric characteristics of poplar seedlings based on 3D visualization via the use of time-of-flight(ToF)and digital cameras was proposed.Firstly,the average distance density function method was applied to process outliers of leaves.Secondly,to improve the accuracy of data fitting,a specific method using the angle of adjacent two-point normal vectors was introduced to filter redundant data,kept essential sample values as the control points,and then used the control points to fit the leaf surface based on non-uniform rational B-splines(NURBS).At the same time,NURBS was used to fit the trunk according to its control points and an iterative method to fit the other branches.Finally,3D visualization of poplar seedlings was achieved,and leaf traits,including leaf width,leaf length,leaf area,and leaf inclination angle,were calculated.To obtain accurate results,multiple experiments were conducted including assessments of poplar seedlings exhibiting normal growth and those grown under water shortage.The results of the proposed method were compared with the real values of the leaves.The RMSE for leaf width,leaf length,leaf area,and leaf angle were 0.18 cm,0.21 cm,1.14 cm^(2),and 1.97°,respectively.The results proved that this approach could be used to accurately measure the leaf characteristics of poplar seedlings via visualization.