The elemental distribution (P, Ca, K, Mg) within inter- and intracellular structure of arbuscular mycorrhizal (AM) cucumber root was determined using energy dispersive X-ray spectroscopy (EDAX). Cucumber (Cucumis sativus cv. Chinesische Schlange) was grown as a test plant using compartmentalized pots with separate zones for hyphal growth and was inoculated or not with the AM fungus, Glomus mosseae (BEG 107). EDAX studies revealed that P in intercellular structures including fungal cells in cucumber root colonized with AM was mainly localized in both polyphosphate granules in arbuscular vacuole and arbuscular cytoplasm. Ca in AM root was mostly localized in cortex cell wall, interfacial apoplast between root and fungus, arbuscular cytoplasm and poly phosphate granules. Mg was distributed homogenously in most cell compartments within AM root while K was localized mainly in cell wall of stele. Higher contents of Ca and Mg were detected in polyphosphate granules whereas lower content of K was detectable. These results indicate that polyphosphate granules could play a role as a complex forming site with metal cations especially with divalent cations like Ca and Mg. In addition, it could give a possibility of regulation function of polyphosphate granules on element transfer from fungus to host plant root. Furthermore, the distribution of element within cortex cytoplasm, interfacial apoplast between plant root and fungus and arbuscular cytoplasm might give a clue on the element transfer mechanism between symbionts.
Yun-Jeong Lee*, Sang-Min Lee, and Seung-Hwan Kim
Carl J. Rosen, Deborah L. Allan, and James J. Luby
providing the cranberry cuttings, Christine Searles for assistance with collecting the soil samples, and Gilbert Ahlstrand for assistance with X-ray microanalysis. The cost of publishing this paper was defrayed in part by the payment of page charges. Under
Gregory M. Glenn and B.W. Poovaiah
Changes in texture, cell wall structure and composition during storage of Ca-treated and untreated `Golden Delicious' apple fruit (Malus domestics Borkh.) were investigated. The cell wall region of Ca-treated fruit showed no swelling during storage and cell-to-cell contact was maintained, whereas regions of the middle lamella in untreated tissue stained lightly, appeared distended, and eventually separated. In control fruit, microfibril orientation was lost in distended regions of the cell wall, especially in the outer wall region adjacent to the middle lamella. Furthermore, the middle lamella was fenestrated and in some cases was completely degraded. These changes during storage of control fruit were accompanied by a decrease in arabinose and galactose moieties of the cell wall and an increase in soluble pectin. Calcium treatment of fruit inhibited solubilization of polyuronide and arabinose moieties and reduced the loss in galactose content during storage. Tensile strength and firmness were positively correlated to Ca content of the fruit cortex. Excessive tensile stress caused tissue failure in control fruit when cells of the cortical tissue separated at the middle lamella. In contrast, cylinders of Ca-treated fruit fractured through cortical cell walls.
Daniel J. Barta and Theodore W. Tibbitts
An electron microprobe was used to determine tissue concentrations of Ca across 20-mm-long leaves of `Green Lakes' crisphead lettuce (Luctuca sativa L.) with and without tipburn injury. Concentrations within the fifth and 14th leaves, counted from the cotyledons, from plants grown under controlled-environment conditions were compared to concentrations within similar leaves obtained from plants grown under field conditions. Only the 14th leaf from plants grown under controlled-environment conditions developed tipburn. Injured areas on these leaves had Ca concentrations as low as 0.2 to 0.3 mg·g-1 dry weight. Uninjured areas of tipburned leaves contained from 0.4 to 0.5 mg·g-1 dry weight. Concentrations across the uninjured 14th leaf from field-grown plants averaged 1.0 mg·g-1 dry weight. Amounts across the uninjured fifth leaves from both environments averaged 1.6 mg·g-1 dry weight. In contrast, Mg concentrations were higher in injured leaves than in uninjured leaves and thus were negatively correlated with Ca concentrations. Magnesium concentrations averaged 4.7 mg·g-1 dry weight in injured leaves compared with 3.4 mg·g-1 dry weight in uninjured leaves from both environments. Magnesium concentrations were uniform across the leaf. Potassium concentrations were highest at the leaf apex and decreased toward the base and also decreased from the midrib to the margin. Potassium averaged 51 mg·g-1 dry weight in injured and uninjured leaves from both environments. No significant differences in K concentration were present between injured and uninjured leaves. This study documented that deficient concentrations of Ca were present in areas of leaf tissue developing tipburn symptoms and that concentrations were significantly higher in similar areas of other leaves that had no symptoms. This study also documented that Ca concentrations were significantly lower in enclosed leaves that exhibited tipburn symptoms than in exposed leaves that did not exhibit tipburn. Also, the amounts of Ca in plants that developed tipburn in controlled environments were lower than in plants of the same cultivar that did not develop tipburn in field plantings. The reduced levels of Ca in plants grown in controlled environments were associated with faster development rates compared with field-grown plants.
Etienne L. LeRiche, Gefu Wang-Pruski, and Valtcho D. Zheljazkov
429 Mohr, W.P. Spurr, A.R. Fenn, P. Timm, H. 1984 X-ray microanalysis of hollow heart potatoes Food Microstruct. 3 41 48 Mondy, N.I. Ponnampalam, R. 1986 Potato
Lee Kalcsits, Gregory van der Heijden, Michelle Reid, and Katie Mullin
. 1970 Calcium transport in apple trees Plant Physiol. 45 670 674 Storey, R. Leigh, R.A. 2004 Processes modulating calcium distribution in citrus leaves. An investigation using X-ray microanalysis with strontium as a tracer Plant Physiol. 136 3838 3848
Sheng Chen, Zhenchang Wang, Zhanyu Zhang, Xiangping Guo, Mengyang Wu, Ghulam Rasool, Rangjian Qiu, and Xiaojun Wang
yield of cotton in a saline field Agron. J. 100 1640 1646 Ebrahimi, R. Bhatla, S.C. 2012 Ion distribution measured by electron probe X-ray microanalysis in apoplastic and symplastic pathways in root cells in sunflower plants grown in saline medium J