摘要:

Developing plastids in young tobacco leaves contain thylakoidal bodies, inclusions bound by a single membrane continuous with stroma lamellae. Both the thylakoidal body and its attached lamellae contain an enzyme that catalyzes an oxidation reaction with 3,3'‐diaminobenzidine (DAB). DAB staining of the thylakoidal body and lamellae is not the result of photo‐oxidation and is inhibited by potassium cyanide. The thylakoidal body disappears as plastids develop into chloroplasts and, further, the lamellar systems of the mature chloroplasts do not stain with DAB. In developing chloroplasts, it is suggested that the thylakoidal body forms by accumulation of protein which stains with DAB within primary lamellae derived from the inner plastid membrane. The ultrastructural and cytochemical evidence suggests that the thylakoidal body stores protein used later in lamellar formation.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1977.tb07609.x

出版商:Wiley    

年代:1977

数据来源: WILEY

摘要:

Light enhanced the penetration of naphthaleneacetic‐1‐14C acid (NAA) into the stomatous lower surface of pear (Pyrus communisL. cv. Bartlett) leaf discs. The light effect was rapidly lost on transfer to the dark and was diminished by pretreatment of leaf discs with a Hill reaction inhibitor (2‐chloro‐4‐ethylamino‐6‐isopropyl‐amino‐s‐triazine). The effect of light on NAA penetration was isolated from its effect on stomatal opening. A similar stimulation of NAA penetration was obtained with stomata opened and closed, providing evidence that penetration did not take place by mass movement into the substomatal chamber.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1977.tb07610.x

出版商:Wiley    

年代:1977

数据来源: WILEY

摘要:

Chromosome numbers are reported for 221 collections from eleven western states. These records represent 85 species included in 48 genera. Counts for the following species are here presented for the first time:Melica spectabilis, Blepharidachne kingii, Eragrostis obtusijlora, Hilaria rigida, Redfieldia flexuosa, andSporobolus interruptus. The record forRedfieldiais also the first for that genus. In addition, numbers which differ from those in the literature are recorded for ten species, in three cases two different numbers for the same taxon. Cytological evidence is also presented indicating thatHilaria jamesiiandH. rigidahave hybridized and that the F1has backcrossed to both parents.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1977.tb07611.x

出版商:Wiley    

年代:1977

数据来源: WILEY

摘要:

The spore wall of the myxomycete,Physarella oblonga, requires only 1 hr to develop. The spore wall surface ornamentations, the warts, are secreted first, followed by an outer electron‐dense layer and an inner electron‐lucent layer. A measurement analysis was conducted to determine if vesicles were involved in wall elaboration. By comparing spore plasmalemma length to the number of fused vesicles, a semi‐quantitative analysis can be obtained. The determination reveals that very few vesicles are associated with wart and outer wall development. The greatest number of vesicles are associated with inner wall secretion. Plasmalemmasomes are most numerous during outer wall formation and Golgi bodies are observed only during inner wall elaboration. Other organelles do not seem directly involved in wall secretion.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1977.tb07612.x

出版商:Wiley    

年代:1977

数据来源: WILEY

摘要:

Cytophotometric measurements of DNA quantity per cell from 45 differentPinus rigidatrees obtained from 135 slides showed that an internal standard was necessary in order to avoid serious errors. Chicken red blood cells were incorporated on the same slide as the pine cells, permitting the calculation of the actual mass units of DNA per pine nucleus. The use of these units makes the results of different investigations and investigators directly comparable. Staining variation between slides and staining batches was shown to be the reason for the requirement of an internal standard. DNA quantity in Feulgen units varied as much as 2.9 fold between different slides of red blood cells although the actual quantity of DNA is constant at 2.8 picograms per nucleus.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1977.tb07613.x

出版商:Wiley    

年代:1977

数据来源: WILEY

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1977.tb07614.x

出版商:Wiley    

年代:1977

数据来源: WILEY

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1977.tb07598.x

出版商:Wiley    

年代:1977

数据来源: WILEY