Stomatal density of pods and leaves were determined for six commercial snap bean cultivars (Phaseolus vulgaris L. `Evergreen', `Hystyle', Labrador', `Tenderlake', `Top Crop', and `Venture') grown at three planting dates, in an attempt to find morphological traits that could be related to cultivar differences in pod Ca concentration. Snap beans were planted three times at ≈1-week intervals beginning 15 June 1995, and harvested 59 to 62 days after planting. Stomatal counts were performed using a microscope linked to a video camera, and Ca concentration determinations were made using atomic absorption spectrophotometry. Calcium concentration and stomatal density of leaf tissue was higher than that of pods. Cultivar differences for pod Ca concentration (P = 0.001) and stomatal density (P = 0.001) were observed although cultivars with higher pod stomatal density did not necessarily result in higher pod Ca concentration. Calcium concentration and stomatal density for leaves did not differ among cultivars. Stomatal density and Ca concentration of pods were positively correlated (R 2 = 0.37), while pod maturity was negatively associated to both pod Ca concentration (R 2 = 0.93), and pod stomatal density (R 2 = 0.99). The effect of planting dates was absent in pod Ca concentration and significant in pod stomatal density.
J.M. Quintana, H.C. Harrison, J.P. Palta, J. Nienhuis, K. Kmiecik, and E. Miglioranza
Angela Hoffman, Clinton Shock, and Erik Feibert
Taxol® (paclitaxel), an important anticancer agent, is found in many species of yew. As the need for Taxol increases, sustainable sources must be found for this drug. Plants often respond to stress with increased production of terpenoid compounds such as Taxol and related taxanes or hormones such as abscisic acid (ABA). To determine whether water stress would enhance the production and recovery of Taxol from stem clippings, 100 young Taxu×media `Hicksii' shrubs were grown for sustainable production of Taxol from stem clippings for two seasons in the dry climate of the Malheur Experiment Station in Ontario, Ore. Shrubs were grown under minimal, moderate, or severe water stress, and the relationships between taxane content and 1) soil and plant water potentials, 2) percentage of stomatal closure, and 3) ABA content were examined. Severely water-stressed shrubs produced significantly more taxanes and ABA than did the less stressed shrubs. Chemical names used: Taxol; 10-deacetyl baccatin III; baccatin III; 10-deacetyl taxol, cephalomannine; 7-epi; 10-deacetyl taxol; abscisic acid. Taxol is a registered trademark of Bristol-Myers Squibb.
Albert H. Markhart III and Mark S. Harper
Leaves on cut stems of commercially grown Rosa hybrida cv. Kardinal placed in preservative solutions containing sucrose developed necrotic dry patches that began interveinally and progressed toward the major veins until the entire leaf was dehydrated. Ultrastructural observations of initial damage showed disorganized protoplasm and plasmolyzed cells. Leaves on cut stems pretreated with abscisic acid for 24 hours and transferred to preservative solution containing sucrose remained healthy. We propose that sucrose accumulates in the mesophyll cell wall, thus decreasing apoplastic osmotic potential, leading to cell collapse and tissue death.
Renuka Rao and Yuncong Li
The review of effects of excessive soil water on performance of various vegetable crops and selected field crops indicates that in areas where temporary flooding hazards are expected during the growing season, crops can be selected on their relative ability to tolerate excessive moisture. Field crops are generally less sensitive than vegetable crops in terms of yield. In addition to the choice of crop species, planting dates could be shifted when possible by delaying dates of sowing or planting to avoid probable periods of flooding during the sensitive growth stages. In most instances, crops are more sensitive at their early developmental phase than at the later stages in terms of yield. Soil management practices like ridging and furrowing or making raised beds before planting is recommended. In addition, amelioration with foliar application of chemicals like nutrients, growth hormones and fungicides is also recommended to overcome nutritional deficiencies, hormonal imbalances and disease infections. Every effort of amelioration should be exerted at the earliest opportunity, since water damage to crops becomes more severe with longer flooding duration.
Fan-Hsuan Yang, Lisa W. DeVetter, Bernadine C. Strik, and David R. Bryla
. Each measurement required 5 to 10 min to obtain a stable reading. Stomatal density and distribution. The number of stomata on the berries was counted using a light microscope (model DM 2500; Leica, Wetzlar, Germany). To prepare the samples, six berries
Abdul K. Janoudi, Irvin E. Widders, and James A. Flore
Abbreviations: A, carbon dioxide assimilation; g s , stomata1 conductance; PFD, photon flux density; RuBPcase, ribulosebisphosphate carboxylase; VPD, vapor-pressure deficit; WUE, water use efficiency. 1 Visiting Research Associate, Plant Research
Madhulika Sagaram, Leonardo Lombardini, and L.J. Grauke
the material. Fig. 1. Collection sites used in the study to investigate leaf anatomic features of pecan cultivars Pawnee, Mohawk, and Starking Hardy Giant. Sample preparation. Pecan leaves are hypostomatic with anomocytic stomata
Carlos Efraín Reyes-González, José Pablo Torres-Morán, Blanca Catalina Ramírez-Hernández, Liberato Portillo, Enrique Pimienta-Barrios, and Martha Isabel Torres-Morán
not the basis leaf. The numbers of adaxial and abaxial stomata were obtained to detect changes in adaptation. Data were obtained using clear nail varnish to make an impression of the epidermis in glass slides and coverslips. Impressions were observed
Weining Wang, Yanhong He, Zhe Cao, and Zhanao Deng
plant breeding and genetic improvement. Following chromosome doubling, autopolyploids may produce larger organs and larger amounts of biomass, have higher biological yields, show changes in anatomical structures (primarily in stomata size and density
Qingling Li, Yuesheng Yang, and Hong Wu
larger stomatas, pollen grains, and seeds ( Abdoli et al., 2013 ; Xu et al., 2013 ). Additionally, flower diameter of tetraploid plants was significantly larger than that in diploid plants ( Abdoli et al., 2013 ). As we all know that flower is the key