Durch Phenylborsäure induzierte Reduktion der Petalen bei Cucumis sativus

Abstract

Heft 20 1959 (Jg. 46) K u r z e Originalmitteiluiigen ~8~ h a s s o m e c h r o m o s o m e s t r u c t u r a l changes s u c h as cryptic deletions in addition to a whole c h r o m o s o m e deficiency. The m e a n n u m b e r of p r i m a r y associations in t h e N.P. 798 nulli-haploid is n o t strikingly different from t h a t characteristic of eu-haploids. This nulli-haploid, therefore, a p p a r e n t l y lacks s o m e c h r o m o s o m e other t h a n the H -H c h r o m o s o m e of RILEY a n d CHAP~aAN ~) or c h r o m o s o m e V of SEARS and OKA~IOTO 4) which are believed to possess a gene s y s t e m responsible for restricting pairing to completely h o m o l o g o u s c h r o m o s o m e s a n d t h e r e b y :for the diploid pairing observed in hexaploid wheat.Secondary associations of t h e side-to-side (s-s), end-toside (e-s) and end-to-end (e-e) t y p e s h a v e been described in eu-haploid w h e a t b y several authors. Their significance is not clear and NATARAJAN a n d SWAMINATttAN 1) h a v e presented d a t a which s u g g e s t t h a t such a t t r a c t i o n s m a y be confined to localized regions of t h e u n i v a l e n t s and bivalents found in t h e haploid. These associations were observed in the nulli-haploid also a n d a s t u d y of t h e relation between the frequency of t h e occurrence of bivalents a n d the f r e q u e n c y of t h e three t y p e s of s e c o n d a r y associations showed t h a t t h e e-e t y p e followed a Poisson law whereas e-s did not. In t h e case of s-s associations the fit for Poisson distribution was good w h e n 0 bivalents and 2 bivalents were present b u t there was a significant d e p a r t u r e w h e n 1 bivalent was present. F r o m our results it appears t h a t e-s and s-s associations m a y show a frequency distribution different from t h a t of e-e associations. PERSONT) has already reported t h a t such a difference exists between e-e and s-s associations in eu-haploid bread wheat.W e are i n d e b t e d to Dr. B . P . PAL, Director a n d Dr. A . B . JosttI, H e a d of the Division of Botany, I n d i a n Agricultural R e s e a r c h I n s t i t u t e for advice and e n c o u r a g e m e n t .In seiner jfingsten Ver6ffentlichung tiber die Biorrelation des W a c h s t u m s y o n Mesokotyl u n d B2oleoptile beim etiolierten Fig. t. Autoradiogramme von drei Haferkeimlingen, die 3 Tage lang mit ~4C-Invertzuckerl6sung fiber die Wurzel versorgt wurden. Bei Pflanze t u n d 3 sind Wurzel (W), Mesokotyl (M), Koleoptile und Prim~rblatt (P) voneinander getrennt. Pflanze 2 ist intakt Haferkeimling stellt MER 1) die H y p o t h e s e auf, dab bei artifizieller Z u c k e r z u f u h r fiber die W u r z e l das K o h l e h y d r a t d e mMesokotyl zufliel3t u n d dessen l u beeinflul3t, nicht aber zur Koleoptile gelangt. Er teilt feriier *nit, dab in seinen V e r s u c h e n der Zucker durch M a n n i t ersetzt werden koniite. Dieses iiberraschende Ergebnis war der AiiIal3, die A u f n a h m e von m a r k i e r t e m Zucker*), der den K e i m l i n g e...