evaluate the relative vigor, as indicated by net photosynthesis and plant growth, of three taxa that grow wild in relatively small areas in the United States and may merit use in managed landscapes: Calycanthus occidentalis Hook. & Arn. (western
J. Ryan Stewart, Reid D. Landes, Andrew K. Koeser, and Andrea L. Pettay
Sara Andrea Moran-Duran, Robert Paul Flynn, Richard Heerema, and Dawn VanLeeuwen
time × N × Ni ( P = 0.0403). Because of the two, three-way interactions involving all factors, significant means for tree group, time, N, and Ni combinations are reported in Table 3 . Table 3. Least square (LS) means for net photosynthesis (μmol·m −2
Richard P. Marini and Donald L. Sowers
`Redhaven' peach [Prunus persica (L.) Batsch] trees were shaded to five light levels [100%, 45%, 23%, 17%, and 9% photosynthetic photon flux (PPF)] for four different periods. Net photosynthesis (Pn), measured under the various shade levels, increased nonlinearly with increasing percent PPF. After 18 days of shading, specific leaf weight (SLW) was positively and linearly related to percent PPF. After shade removal, Pn and SLW returned to control levels in 26 and 4 days, respectively. Flower density was positively related to percent PPF when trees were shaded from 16 June to 4 July or 4-31 July, but not from 31 July to 30 Sept. of the previous year.
S.E. Garrison, J.M. Williams, and J.A. Barden
A greenhouse experiment was conducted to determine the effects of shade treatments (0, 30, 47 and 63%) on photosynthetic and growth responses of `Redchief' strawberries. Net photosynthesis (Pn) measured on plants under shade decreased as % shade increased. Pn of plants grown under shade but measured under saturating light intensities decreased after 30% shade. Light saturation curves of leaves allowed to expand in full sun and then placed under shade indicated a decrease in the saturation rate and point under 63% shade. Leaves which expanded under shade had decreased saturation rates and points at all levels. Specific leaf weight and total plant dry weight decreased linearly as % shade increased.
A field study in which plants were either shaded in the fall or in the fall and spring demonstrated a decreasing trend in berry number for plots which were shaded in the fall and spring. Berry number decreased in fall-shaded plants after 30% shade. In both cases, berry weight decreased with increasing shade.
E.D. Leonardos, M.J. Tsujita, B. Grodzinski, and T.J. Blom
Gas exchange (net photosynthesis Pn, dark respiration, transpiration, and stomatal resistance) of `Jaqueline' Alstroemeria, grown in pots in a greenhouse, were measured. Measurements were made under laboratory conditions using an open-flow infrared gas analysis system for leaf studies, and a semi-closed computer controlled whole plant photosynthesis system for whole plant studies.
Apical fully expanded leaves on non-flowering and flowering (at two stages) shoots had similar photosynthetic responses in respect to photosynthetically active radiation (PAR) and to CO2 concentration. Light saturation occurred at 600 umol/m2/s PAR with maximum leaf Pn rates ranging from 9 to 11 umol CO2/m2/s. CO2 saturation was estimated at approximately 1100 to 1200 ppm with maximum leaf Pn rates from 17 to 22 umol CO2/m2/s.
Whole plant Pn rates increased with increased PAR. Maximum rates 4 to 5 umol CO2/m2/s (half that of individual leaves) occurred at approximately 1000 to 1100 umol/m2/s PAR. CO2 saturation was estimated at 1100 to 1200 ppm, with maximum whole plant Pn rates ranging from 7 to 8 umol CO2/m2/s. These data will be discussed in relation to respiration and mutual shading at the leaf canopy.
J.H. Lieth and C.C. Pasian
A mathematical description for the relationship between the rate of rose (Rosa hybrida L.) leaf net photosynthesis and photosynthetically active radiation, leaf temperature, and leaf age is developed. The model provides a tool for the prediction of these rates for leaves growing in a rose crop canopy.
Bharat P. Singh, Kevin A. Tucker, James D. Sutton, and Harbans L. Bhardwaj
Abbreviations: E, transpiration; g s , stomatal conductance; Pn, net photosynthesis; ψ, leaf water potential. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations
David C. Ferree
Abbreviations: Pn, net photosynthesis, SSC, soluble solids concentration. Journal article no. 1-92. Salaries and research support provided by state and federal funds appropriated to the Ohio Agricultural Research and Development Center, The Ohio
Kendrick N. Mobley and Richard P. Marini
Abbreviations: DAT, days after treatment; ERM, European red mite; Pn, net photosynthesis; SLW, specific leaf weight; TCHL, total chlorophyll; Tr, transpiration; TSM, twospotted spider mite; WUE, water-use efficiency. 1 Graduate Student. 2 Associate
Richard J. Campbell, Richard P. Marini, and Jeffrey B. Birch
Abbreviations: FB, full bloom; Pn, net photosynthesis; PPFD, photosynthetic photon flux density. 1 Dept. of Horticulture. 2 Dept. of Statistics. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal