| dc.description.abstract | 【Objective 】Distribution of mineral nutrition in plant tissues reflects the
patterns of nutrient transportation and utilization. Using calcium analysis in fruit
tissues as an example, this paper demonstrates a method that combines electron probe
microanalysis and image processing technique, which generates a direct review of in
situ mineral distribution in plant tissues. 【Materials】Pedicels and pericarps of mature
fruits of litchi cv. Huaizhi and citrus cv. Shatangju and pedicels of persimmon cv.
Cilang were used as materials for this study. Tissue slices coated with platinum were observed under scanning electron microscope equipped with an electron probe (wave dispersive spectroscopy, WDS). Secondary electron images and Ca-specific X-ray signal mapping images (Ca mapping image) were separately collected. The map of
bright dots representing abundance of Ca were extracted using image processing
Photoshop and combined with the secondary electron image. 【Results】The combined
image provided direct review of detailed in situ Ca distribution in fruit tissues. In the
pedicels of all the tree fruit species, Ca abundance in the phloem is significantly
greater than in the xylem. Within the phloem, fiber cells have the lowest Ca content,
while the parenchyma cells contain higher calcium. Many of these cells have Ca-rich
bodies (calcium oxalate crystals). The epiderm of litchi pericarp has high calcium and
also contain Ca-rich bodies. Pericarp of citrus has a relatively even Ca distribution.
【Conclusion】Electron probe combined with image processing technique provides an
effective method for observing in situ nutrition distribution in plant tissues. According
to the distribution pattern of Ca in fruit pedicel, it is suggested that Ca transport to
fruit is likely through the phloem instead of xylem. | en_US |
