Rudolf Herich

The effect of cobalt on the structure of chromosomes and on the mitosis

SummaryCobalt exerts an effect on the structure of chromosomes and on the course and intensity of cell division in root tips of Vicia faba is.Despiralisation of chromosomes and an increase of the viscosity of the matrix substance causing stickiness of the chromosomes are induced by the treatment with cobalt.A cytostatic effect of cobalt was observed. The intensity of cell division is strikingly reduced after treatment with cobalt. Cobalt inhibits the passage of interphase cells into prophase so that this element can be considered to be a preprophase poison.

Nucleoli and cytoplasmic male sterility

SummaryThe paper describes the relation of cytoplasmic male sterility and the differentiation of nucleoli. Defects in the formation of nucleoli of pollen grains of maize with cytoplasmic male sterility were observed whereas the nuclei of control, i.e. fertile maize contained always only a single nucleole. In the nuclei of sterile pollen grains nucleoli of various sizes and numbers are formed.

Existence of Membrane-like Lysosomal Formations in Plant Cells

Summary Electronmicroscope studies of tranformation of membrane-like complex of endoplasmic reticulum into a lysosomal formation are decribed.

Can mitochondria from proplastids be differentiated

Die &ul3ere E r y t h r o c y t e n M e m b r a n wird d u t c h n e u r a m i n s~ure-ha l t ige Glykopro te ine (NG) a u f g e b a u t [1~. Sie s ind mal3geblich an der n e g a t i v e n L a d u n g dieser Zellen betei l igt [2]. Der gr6Bte Tell der N G k a n n in un te r sch ied l i che r ~Veise yon ve r sch iedenen P ro t ea sen dazu e ignet sich insbes. P ronase yon der E ry th rocy t en -Obe r f l ~che a b g e t r e n n t werden [3]. Es zeigte sich, dab n ich t n u r q u a n t i t a t i v e Un te r sch i ede im N G GehMt y o n E r y t h r o c y t e n versch iedener H e r k u n f t bes tehen , sonde rn dab derar f ige Dif ferenzen s u c h inne rha lb einer Art , wahrsche in l i ch d u r c h gene t i sche Einflt~sse bedingt , b e o b a c h t e t werden k 6 n n e n [4]. p rop las t ids a n d mi tochond r i a are capable of A T P bonding . The onIy difference be tween t h e m is t h a t t h e p h o s p h o r y l a t i o n t a k i n g place is p h o t o s y n t h e t i c in p las t ids a n d ox ida t ive in m i tochond r i a [2~. Our e x p e r i m e n t a l s tudies were pe r fo rmed on mer i s t em a t i c cells of roo t t ips of Vicia labs. The ma te r i a l was f ixed in 1.2% solu t ion of K M n O 4 in ve rona l ace ta t e buffer a t p H 7 an d t h e ma te r i a l was e m b e d d e d in D u r c u p a n ACM Fluka . I n these s tudies we h a v e observed an in t e re s t ing p h e n o m e n o n . F r o m prop las t id s t r o m a were d i f fe ren t ia ted fo rmat ions , r e sembl ing mi tochondr i a in the i r appea rance and size. These fo rma t ions or ig ina te by i nvag ina t i on and folding back of t h e inner l imi t ing m e m b r a n e of t he p rop las t id (Fig. 1). I n th i s process, a por t ion of s t r o m a is s epa ra t ed f rom prop las t id s t r oma ; t he por t ion of the s t r o m a r ema ins ini t ia l ly connec ted to proplas t id s t r o m a b y m e a n s of the ou te r l imi t ing m e m b r a n e .