Preformed adventitious root initiation in brittle willows grown in a controlled environment

1970 ◽  
Vol 48 (12) ◽  
pp. 2309-2312 ◽  
Author(s):  
Bruce E. Haissig
Keyword(s):  
Environmental Conditions ◽  
Adventitious Root ◽  
Controlled Environment ◽  
Root Initiation ◽  
Root Primordia ◽  
Initial Formation ◽  
Cellular Physiology ◽  
Secondary Thickening

Nodal preformed adventitious root primordia of brittle willow develop from initial cells which appear first and only in the fourth node below the terminal leaf cluster of plants grown under the described environmental conditions. The onset of root initial formation is related to the cessation of rapid aerial development which occurs at node 4, and also with the start of secondary thickening which occurs in this node. Brittle willow is an ideal subject with which to study the cellular physiology of root initials since nodes showing the earliest stages of root initial formation and development can be selected. In addition, the root initials are readily located in histological preparations.

Initiation of adventitious root primordia in very young Pinusbanksiana seedling cuttings

1983 ◽  
Vol 13 (1) ◽  
pp. 191-195 ◽  
Author(s):  
Cheryl R. Montain ◽  
Bruce E. Haissig ◽  
John D. Curtis
Keyword(s):  
Transition Zone ◽  
Adventitious Root ◽  
Secondary Xylem ◽  
Vascular Cambium ◽  
Root Initiation ◽  
Secondary Phloem ◽  
Root Primordia ◽  
Cortical Cells ◽  
Parenchyma Cells ◽  
Resin Canals

The present work describes the anatomy of adventitious root initiation in 20-day-old Pinusbanksiana Lamb, seedling cuttings propagated under intermittent mist. Shortly after cuttings were made, basal necrosis occurred in all tissues (epidermis, periderm, cortex, primary and secondary phloem, and vascular cambium) that surrounded the central xylem cylinder. Thereafter, a relatively small "callus complex" composed of parenchyma cells, a few secondary xylem tracheids, and incompletely differentiated callus vascular cambium and periderm developed at the base of cuttings. One or sometimes two root primordia initiated in the transition zone between the lowermost cortical cells of the hypocotyl and the uppermost callus parenchyma cells. Primordia invariably arose just outside one of the four axial resin canals in the hypocotyl. Results suggested that adventitious root primordia may be initiated in P. banksiana cuttings only in association with differentiated or differentiating resin canals.

scholarly journals Adventitious root primordia formation and development in the stem of Ananas comosus var. bracteatus slip

2021 ◽  
pp. 1949147
Author(s):  
Mark Owusu Adjei ◽  
Yixuan Xiang ◽  
Yehua He ◽  
Xuzixin Zhou ◽  
Meiqin Mao ◽  
...  
Keyword(s):  
Adventitious Root ◽  
Ananas Comosus ◽  
Root Primordia

Early biochemical events during adventitious root initiation in the hypocotyl of Phaseolus vulgaris

1979 ◽  
Vol 18 (3) ◽  
pp. 383-387 ◽  
Author(s):  
G.R. Kantharaj ◽  
S. Mahadevan ◽  
G. Padmanaban
Keyword(s):  
Phaseolus Vulgaris ◽  
Adventitious Root ◽  
Root Initiation

scholarly journals Development of MILIONCAST, an Improved Model for Predicting Downy Mildew Sporulation on Onions

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 695-702 ◽  
Author(s):  
Tijs Gilles ◽  
Kath Phelps ◽  
John P. Clarkson ◽  
Roy Kennedy
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Temporal Pattern ◽  
Random Model ◽  
Controlled Environment ◽  
High Humidity ◽  
Potted Plants ◽  
Effects Of Temperature ◽  
Improved Model ◽  
Accuracy Of Prediction

The effects of temperature and relative humidity on Peronospora destructor sporulation on onion (Allium cepa) leaves were studied under controlled environmental conditions. Sporangia were produced most rapidly at 8 to 12°C after 5 h of high humidity during dark periods. The greatest number of sporangia was produced at 100% relative humidity (RH), and sporulation decreased to almost nil when humidity decreased to 93% RH. A model, named MILIONCAST (an acronym for MILdew on onION foreCAST), was developed based on the data from these controlled environment studies to predict the rate of sporulation in relation to temperature and relative humidity. The accuracy of prediction of sporulation was evaluated by comparing predictions with observations of sporulation on infected plants in pots outdoors. The accuracy of MILIONCAST was compared with the accuracy of existing models based on DOWNCAST. MILIONCAST gave more correct predictions of sporulation than the DOWNCAST models and a random model. All models based on DOWNCAST were more accurate than the random model when compared on the basis of all predictions (including positive and negative predictions), but they gave fewer correct predictions of sporulation than the random model. De Visser's DOWNCAST and ONIMIL improved their accuracy of prediction of sporulation events when the threshold humidity for sporulation was reduced to 92% RH. The temporal pattern of predicted sporulation by MILIONCAST generally corresponded well to the pattern of sporulation observed on the outdoor potted plants at Wellesbourne, UK.

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