Tree Seedling Growth: Effects of Shaking

Abstract

and second, there is a twofold difference We do not feel that we have confounded age with location in our studies. As we said, "we studied two adjacent abandoned hayfields," and "macroclimate and soil series are identical." Both fields were planted in timothy (Phleum pratense) and are slowly decaying into "natural" ecosystems characteristic of upstate New York. Since timothy is hardly a species characteristic of impoverished sites (1), we assume that whatever impoverishment leads to invasion of Poa compresa and Hieraciuim pratense arises out of the successional aging process. We have extensive soil data on the two fields as well as a description of their previous land usage from the land's owner. These data could not be included in a report in Science.

Wind-induced plant motion immediately increases cytosolic calcium.

“…3 suggest that touch responses mimic the attenuation produced by continual wind stimulation. Since it will be very difficult to touch a plant without concomitant movement, the thigmomorphogenic response described by Jaffe (18) and other mechanostimulatory responses described by others (3)(4)(5)(6)(19)(20)(21)(22) may simply represent a response to tissue motion and the ensuing transient change in tension and compression of constituent cells. Touch stimulation without concomitant tissue movement may not normally be a reality.…”

“…Nothing is yet known concerning the perception or transduction of wind signals although immediate effects on respiration have been noted (2). It is believed that the morphological alterations result from wind-induced changes in transpiration and gas exchange but a contribution from wind-induced movement has occasionally been suggested (1,(3)(4)(5). It has been observed that shaking Liquidambar seedlings for 30 s a day reduced their subsequent height after 3 weeks to 20-30o of that of untreated seedlings and often induced premature dormancy (4).…”

Ethylene and Not Embolism Is Required for Wound-Induced Tylose Development in Stems of Grapevines

“…Clearly, conditions that trigger tylosis are also conditions that stimulate ethylene biosynthesis, leading us to suppose that the role of ethylene in tylosis formation might be quite general. Ethylene is known to regulate diverse physiological and metabolic activities in plants and to be involved in many aspects of growth and development of cells and tissues (Mattoo and Suttle, 1991;Reid, 1995), including xylem development (Parkhurst et al, 1972). This suggested to us that ethylene could be a coordinating factor in the development of tyloses.…”

Phenotypic Plasticity Early in Life Constrains Developmental Responses Later

“…In response to contact or wind, many species exhibit reduced leaf, branch, and stem lengths and increased stem diameter (Parkhurst and Pearman 1972;Telewski and Pruyn 1998). Relatively small perturbations reduce elongation.…”