terminal stage sampling as the plant appeared to wilt and began ending growth (67 d PT). At each assessment, four randomly selected plants from each treatment group (eight plants total) were dissected and the roots, stems, leaves, and fruit (if present) of
Leslie D. Hintz, Renee R. Boyer, Monica A. Ponder, Robert C. Williams, and Steven L. Rideout
Thomas E. Marler
breeding programs were included in each experiment. Objectives were to compare the rapidity and extent of plasticity of growth under ambient wind exposure among papaya leaves, stems, and roots to more fully understand how these responses are coordinated
Donald R. Hodel
history, stems (trunks), roots, leaves, and inflorescences, and how they impact management in the landscape. Fig. 1. Elegantly capturing that so-sought exotic and tropical motif, palms can be likened architecturally to an elongated axis (stem or trunk
Z. Wang and B. Quebedeaux
Light duration alters carbon partitioning among carbohydrates (CHOs) in source leaves. The current experiments were designed to determine how light duration affected the metabolism of newly fixed and reserve CHOs in various organs of apple and whether longer durations favored sorbitol (sor) synthesis. One-year-old `Gala' apple plants that experienced a 1-, 4-, 7-, 10-, or 14-h photoperiod for 7 d were exposed to 14CO2 for 15 min. Individual CHO concentrations and the activity of newly-fi xed [14C]CHOs in leaves, stems, and roots were analyzed during different intervals after labeling. In source leaves, sor increased significantly, whereas sucrose (suc) did not change as light duration increased from 1 to 10 h, resulting in increased sor/suc ratios from 2.6 in the 1-h to 4.3 in the 10-h light duration. The increased sor/suc ratios may be due primarily to the preferential carbon partitioning into sor in longer light durations. Longer light durations enhanced the sor export rate from source leaves, resulting in higher sor in stems and sink tissues. In roots, starch increased significantly over increasing light durations. A major portion of starch in roots may be converted from newly fixed CHO. Our results suggest that light duration alters the metabolism of sor and other CHOs in source and sink tissues of apple and that the changes in CHO concentrations result from different rates of carbon synthesis, partitioning, and export.
Chloride stress in commercial citrus is predominantly a result of increased osmotic pressure in the plant as a result of excess chloride. The source of the chloride is usually from the soil solution, where it is absorbed by the roots. After being absorbed, chloride flows through the xylem in the transpiration stream to the shoot, where it is accumulated by transpiring tissues such as leaves and fruit. Monitoring chloride concentration along any of these steps can be used to assess potential stress in the tree. Since some of these tissues tend to accumulate chloride (fruit and leaves) while others do not (root and xylem), analyses should be interpreted within the context of these differences. Having high chloride concentration in roots or xylem-water at a specific sampling time does not necessarily mean that leaves have already accumulated chloride to a toxic level, while having high chloride concentration in fruit or leaf analysis does not necessarily mean that the trees are still being exposed to high salinity in the soil solution. The advantages of the various analyses, as well as their difficulties, are discussed. It was concluded that a combination of xylem sap chloride analysis and leaf chloride analysis are the most useful tools for assessing potential chloride stress in citrus trees.
C.F. Scagel, K. Reddy, and J.M. Armstrong
In a commercial nursery propagation system for hick's yew (Taxu×media `Hicksii'), we assessed whether or not the addition of inoculum of the vesicular-arbuscular mycorrhizal fungus (VAMF) Glomus intraradices into the rooting substrate during cutting propagation increased rooting, and how the quantity of inoculum influenced rooting. At 15 and 22 weeks (108 and 156 d) after cuttings were treated with root hormones and stuck, root initiation was higher on cuttings stuck in the rooting substrate containing VAMF inoculum. Increasing the quantity of inoculum in the rooting substrate increased root growth during the early stages of rooting. However the highest level of inoculum tested increased adventitious root initiation without increased root growth. Our results indicate that if VAMF inoculum is used during propagation from cuttings, there are optimal levels required to alter the initiation and growth of roots. For hick's yew, 1:100 or 2:100 (by volume) rates of G. intraradices in the rooting substrate increased the number of primary roots and growth of adventitious roots on cuttings above that achieved by using rooting hormone alone.
flower bulbs as it is composed of the basal root system and the stem root system. The fleshy basal roots grow at the basal plate under the bulb, while after the shoot has emerged from the soil and grown to a certain height, the stem roots will grow as
Michael T. Martin Jr., Geoffrey M. Weaver, Matthew R. Chappell, and Jerry Davis
as it allows for plants with preferred traits to be propagated asexually and thereafter perpetuated indefinitely. The process by which excised stem sections develop adventitious roots can be divided into two distinct stages; cells of the existing
Rangjian Qiu, Zaiqiang Yang, Yuanshu Jing, Chunwei Liu, Xiaosan Luo, and Zhenchang Wang
varying EC iw , the K + , Na + , and Ca 2+ concentrations and K + /Na + ratio in hot pepper roots and stems were also studied. The aim of this study is to evaluate the effects of EC iw on growth (i.e., plant height; SD; leaf length; leaf area; and the
Claudia Fassio, Ricardo Cautin, Alonso Pérez-Donoso, Claudia Bonomelli, and Mónica Castro
plants were separated into stems, leaves, and roots, and the tissues were dried in a forced-air oven at 70 °C for 72 h for biomass determination. The shoot dry weight was equal to the sum of the aerial vegetative plant parts (leaves + stems). The root