Studies of Calcification in Plants 157 



development, do not produce an electron diffraction pattern. Mature crystals give an 

 X-ray diffraction pattern characteristic of calcium oxalate monohydrate. No special 

 differentiation of plastids was observed in the Lemna idioblasts; however, the cells 

 are exceptionally well provided with Golgi bodies, endoplasmic reticulum and mito- 

 chondria. 



In the shoot of the water hyacinth (Eichhornia), raphide idioblasts with over 

 2000 crystals per cell were observed; cells with 2140 (Fig. 3) and 2012 crystals were 

 counted. Paradoxically, in the same tissue cells having only a single crystal per cell 

 are quite common (Fig. 4). In principle, the development of the raphide cell with its 

 many needle shaped crystals and the styloid cells with one (or a few) large tabular 

 shaped crystals is the same. In each case the crystals form within a chamber produced 

 in the crystal vacuole. As in Lemna, the crystal chambers of Eichhornia are in 

 intimate association with a series of tubules and membranes which extend into the 

 crystal vacuole from the peripheral cytoplasm. In this case it is clear that if a cell is 

 to produce over 2000 crystals in close proximity to each other, it must exercise more 

 or less complete control of the process, /'. e., crystal formation in plants may have 

 physical and chemical parameters but it is a biological controlled phenomenon. 



Summary 



The formation of calcium oxalate crystals in the plants investigated is a 

 biologically controlled process, intimately associated with cellular differentiation. 

 Crystal development occurs by the formation of loaded chambers associated with 

 membranes and tubules; subsequently crystals are formed within these chambers. The 

 possibility that the chamber acts like a boule is suggested. 



Acknowledgments 

 I sincerely thank Prof. W. G. Whaley for his encouragement and for the use of 

 the facilities of the Cell Research Institute. The present research was supported in 

 part by N.S.F. Grant GF-1458 and N.I.H. 5TIGM 789. 



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