Abbreviations: RN, root nutrient; RW, root weight; SF, soil fertility. 1 Professor Emeritus, Dept. of Horticultural Science. 2 Associate Professor, Dept. of Soil Science. Paper no. 12055 of the Journal Series of the North Carolina Agricultural
T.R. Konsler and J.E. Shelton
T.R. Konsler, S.W. Zito, J.E. Shelton and E.J. Staba
Soil-applied dolomitic limestone and fertilizer affected the level of certain root and leaf ginsenosides in 4-year-old American ginseng (Panax quinquefolium L.); however, ginsenoside accumulations in the roots and in the leaves often were not similar. Root and leaf ginsenoside production tended to differ in its response to soil fertility (SF) factors and root tissue nutrient (RN) elements. Leaf ginsenoside production was more often correlated with SF factors and RN elements than that of root ginsenosides, the response of both ginsenoside sources was greater to RN than SF status. Leaf ginsenoside content was positively correlated with the SF factors and RN elements to a greater degree than that of root ginsenosides. Leaf ginsenoside production was more often affected by the same chemical element in the soil and in root tissue than that of root ginsenosides. There was no correlation between the level of any ginsenoside measured in root tissue and the same ginsenoside in leaf tissue.
Patrick E. McCullough, Haibo Liu, Lambert B. McCarty, Ted Whitwell and Joe E. Toler
Dwarf-type bermudagrasses [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davey] tolerate long-term golf green mowing heights but require heavy nitrogen (N) fertilizations. Inhibiting leaf growth with trinexapac-ethyl (TE) could reduce shoot growth competition for root reserves and improve nutrient use efficiency. Two greenhouse experiments evaluated four N levels, 6 (N6), 12 (N12), 18 (N18), and 24 (N24) kg N/ha/week, with TE at 0 and 0.05 kg·ha–1 a.i. every 3 weeks to assess rooting, nutrient allocation, clipping yield, and chlorophyll concentration of `TifEagle' bermudagrass grown in PVC containers built to U.S. Golf Association specification. Trinexapac-ethyl enhanced turf quality on every date after initial application. After 8 weeks, high N rates caused turf quality decline; however, TE treated turf averaged about 25% higher visual quality from nontreated turf, masking quality decline of high N fertility. `TifEagle' bermudagrass treated with TE had clippings reduced 52% to 61% from non-TE treated. After 16 weeks, bermudagrass treated with TE over all N levels had 43% greater root mass and 23% enhanced root length. Compared to non-TE treated turf, leaf N, P, and K concentrations were consistently lower in TE treated turf while Ca and Mg concentrations were increased. Root N concentrations in TE treated turf were 8% to 11% higher for N12, N18, and N24 fertilized turf than respective N rates without TE. Compared to non-TE treated turf, clipping nutrient recoveries were reduced 69% to 79% by TE with 25% to 105% greater nutrients recovered in roots. Bermudagrass treated with TE had higher total chlorophyll concentrations after 8 and 12 weeks. Overall, inhibiting `TifEagle' bermudagrass leaf growth appears to reallocate nutrients to belowground tissues, thus improving nutrient use efficiency and root growth. Chemical name used: trinexapac-ethyl, [4-(cyclopropyl-[α]-hydroxymethylene)-3,5-dioxo-cyclohexane carboxylic acid ethylester].
Sandra B. Wilson, P. Chris Wilson and Joseph A. Albano
Invasive species have disrupted thousands of acres of natural areas in Florida and appear to have a physiological competitive advantage over native species. The influence of light and temperature on germination was determined for the invasive Mexican petunia (Ruellia tweediana Griseb.) and native wild petunia (Ruellia caroliniensis Steud.). Seeds were collected and germinated in incubators with light or darkness at 15, 24, 33, and 30/20 °C. Light increased germination for each species, except at 15 °C (R. caroliniensis). For R. caroliniensis, highest germination (86% to 94%) occurred at 33 °C and 30/20 °C. Highest germination of R. tweediana (98% to 100%) occurred at 30/20 °C. Studies also were initiated to determine if R. tweediana has a competitive advantage over the native species when grown under wet and dry substrate conditions. Growth and development measurements after 8 weeks under controlled conditions revealed that R. tweediana grown in wet conditions had the greatest dry weight increase as compared to other treatments. Ruellia caroliniensis had higher specific leaf area when grown in wet or dry conditions, as compared to R. tweediana. Throughout the experiment, net CO2 assimilation of R. caroliniensis grown under dry or wet conditions was consistently lower than that of R. tweediana. Shoot nitrogen and phosphorus use efficiencies were generally greatest for R. tweediana plants grown in wet conditions. For shoot nutrient content, significant species × moisture interactions occurred for measured phosphorus (P) and calcium (Ca). When grown in wet conditions, R. tweediana had less shoot P and Ca as compared to dry conditions. For root nutrient content, species × moisture interactions were insignificant for each measured nutrient, with the exception of potassium (K). Potassium use efficiency of R. tweediana roots grown in wet conditions was higher than that of R. tweediana grown in dry conditions and R. caroliniensis grown in wet conditions.
Qin Shi, Yunlong Yin, Zhiquan Wang, Wencai Fan, Jinbo Guo and Jianfeng Hua
= vacuole. Root nutrients and growth traits. TN concentration of T . 406 roots in DS-12 treatment increased significantly ( P < 0.05) compared with that in CK-12 and DS-8 treatments, respectively. The contents of TN were the least ( P < 0.05) in DS-8
Liang Cheng, Ning Zhang and Bingru Huang
length, volume, surface area, and diameter. Shoot and root nutrient analysis. Roots were washed free of fritted clay and severed from shoots at 20 d after salinity initiation. They were washed with deionized water and dried at 80 °C for 3 d. The dry plant
Amaya Atucha and Greg Litus
plants ( n = 9) per treatment at 11, 22, and 33 weeks after planting. Roots were washed free of adhering soil, and cleaned roots were placed in individual paper bags, dried for 2 d at 60 °C and weighed for dry biomass. Leaf and root nutrient content. To
Luisa Dalla Costa, Nicola Tomasi, Stefano Gottardi, Francesco Iacuzzo, Giovanni Cortella, Lara Manzocco, Roberto Pinton, Tanja Mimmo and Stefano Cesco
respiration, despite the tight linkage between root nutrient uptake and respiration, it should not be assumed that increased soil temperature would affect root nutrient uptake as a linear function of root respiration ( Bassirirad, 2000 ). Dong et al. (2001
Dimitrios Savvas, Dimitrios Papastavrou, Georgia Ntatsi, Andreas Ropokis, C. Olympios, Hagen Hartmann and Dietmar Schwarz
concentration. Table 2. Root nutrient concentrations in ‘Belladona’ or ‘He-Man’ grafted with scions of tomato (‘Belladona’ F 1 ) grown in a recirculating nutrient solution as influenced by the manganese (Mn) level in the nutrient solution introduced to
Carolyn F. Scagel and Jungmin Lee
least root nutrient content (content data not shown). ‘Cinnamon’ had the greatest root K and Mn concentrations and root N, P, K, S, Ca, B, Mn, and Zn content. ‘Sweet Dani’ had the greatest root Mg concentrations and root Mg and Fe content. ‘Siam Queen