HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Haagenson, D. M. Articles by Volenec, J. J. Search for Related Content PubMed Articles by Haagenson, D. M. Articles by Volenec, J. J. Agricola Articles by Haagenson, D. M. Articles by Volenec, J. J. Related Collections Forage Management Alfalfa Plant and Environment Interactions Temperature Stress

Autumn Defoliation Effects on Alfalfa Winter Survival, Root Physiology, and Gene Expression

Dep. of Agronomy, Purdue Univ., West Lafayette, IN 47907-1150 USA

View larger version (54K): [in a new window]   Fig. 1. Effect of autumn defoliation on (A) starch and (B) sugar concentrations of alfalfa roots sampled in late November. Alfalfa was cut on 7 September (control) and at weekly intervals from 2 October through 12 November. Error bars represent one standard error of the mean (n = 4). Exp. 1.

View larger version (46K): [in a new window]   Fig. 2. Effect of autumn defoliation on (A) amino N and (B) buffer-soluble protein concentrations from alfalfa roots harvested in late November. Alfalfa was cut on 7 September (control) and at weekly intervals from 2 October through 12 November. Error bars represent one standard error of the mean (n = 4). Exp. 1.

View larger version (71K): [in a new window]   Fig. 3. Sodium dodecylsulfate polyacrylamide gel electrophoresis and immunoblot analyses of buffer-soluble proteins extracted from alfalfa taproots in late November. (A) Buffer-soluble protein (25 µg per lane) stained with Coomassie Brilliant Blue R-250. Molecular mass standards (kDa) are listed to the left. (B) Protein gel blot containing 5 µg protein per lane was probed using antisera raised to the 15 and 32 kDa vegetative storage proteins. Samples were loaded in lanes according to their respective cutting dates: Lane 1, 7 September; Lane 2, 2 October; Lane 3, 8 October; Lane 4, 15 October; Lane 5, 22 October; Lane 6, 29 October; Lane 7, 6 November; Lane 8, 12 November. Exp. 1.

View larger version (42K): [in a new window]   Fig. 4. Minimum air and soil (10-cm depth) temperatures at the Agronomy Research Center, West Lafayette, IN. Dates of the first killing freeze (-4°C) were 5 Nov. 1998 and 15 Nov. 1999. Exp. 2.

View larger version (43K): [in a new window]   Fig. 5. Effect of October defoliation on alfalfa (A) winter injury and (B) spring height. One half of plants in each plot were defoliated in October. Winter injury and spring height were assessed in April. Winter injury ratings are weighted means based on mid-April observations of 20 to 30 plants using the following scoring scale: 1 = no injury, 2 = injured plant, and 3 = dead plant. Included in the study were the dormant cultivars ‘53Q60’ (Q60) and ‘54H69’ (H69), the nondormant cultivar ‘5939’, and three semidormant germplasms: 96P51PSI (P51), Z57NO2 (NO2), and 96P55PSI (P55). Error bars represent one standard error of the mean (n = 8). Exp. 2.

View larger version (71K): [in a new window]   Fig. 6. Effect of October defoliation on starch (A) and soluble sugar (B) concentrations in alfalfa taproots. One half of plants in each plot were defoliated in October. Roots were sampled in October at the time of defoliation, and in December. Included in the study were the dormant cultivars ‘53Q60’ (Q60) and ‘54H69’ (H69), the nondormant cultivar ‘5939’, and three semidormant germplasms: 96P51PSI (P51), Z57NO2 (NO2), and 96P55PSI (P55). Error bars represent one standard error of the mean (n = 7). Exp. 2.

View larger version (39K): [in a new window]   Fig. 7. Effect of October defoliation on (A) sucrose, (B) raffinose, and (C) stachyose concentrations in alfalfa taproots sampled in December. One half of plants in each plot were defoliated in October. Included in the study were the dormant cultivars ‘53Q60’ (Q60) and ‘54H69’ (H69), the nondormant cultivar ‘5939’, and three semidormant germplasms: 96P51PSI (P51), Z57NO2 (NO2), and 96P55PSI (P55). Error bars represent one standard error of the mean (n = 7). Exp. 2.

View larger version (72K): [in a new window]   Fig. 8. Effect of October defoliation on (A) amino N and (B) buffer soluble protein concentrations in alfalfa taproots. One half of plants in each plot were defoliated in October. Roots were sampled in October at the time of defoliation, and in December. Included in the study were the dormant cultivars ‘53Q60’ (Q60) and ‘54H69’ (H69), the nondormant cultivar ‘5939’, and three semidormant germplasms: 96P51PSI (P51), Z57NO2 (NO2), and 96P55PSI (P55). Error bars represent one standard error of the mean (n = 7). Exp. 2.

View larger version (100K): [in a new window]   Fig. 9. Sodium dodecylsulfate polyacrylamide gel electrophoresis and immunoblot analysis of buffer-soluble proteins extracted from alfalfa taproots in early December. Twenty-five micrograms of soluble protein were analyzed per lane, and proteins were stained with Coomassie Brilliant Blue R-250 (A). Molecular mass standards (kDa) are listed to the left. Protein gel blots containing 5 µg protein per lane were analyzed using antisera from the 15 and 32 kDa vegetative storage proteins (B). Alfalfa plants were cut in October (C) or uncut (U). Included in the study were the dormant cultivars ‘53Q60’ (Q60) and ‘54H69’ (H69), the nondormant cultivar ‘5939’, and three semidormant germplasms: 96P51PSI (P51), Z57NO2 (NO2), and 96P55PSI (P55). Exp. 2.

View larger version (48K): [in a new window]   Fig. 10. RNA blot analysis of root cold hardiness gene expression of six alfalfa cultivars with contrasting fall dormancy and winter hardiness. Twenty micrograms of total RNA was loaded per lane and blots were hybridized with three 32P-labeled cold-acclimation responsive cDNAs: bN-1 12a3, RootCar1, and bC2E 40a. Alfalfa plants were cut in October (C) or uncut (U). Roots were sampled at the time of defoliation in October or after a period of cold acclimation in December. Included in the study were the dormant cultivars ‘53Q60’ (Q60) and ‘54H69’ (H69), the nondormant cultivar ‘5939’, and three semidormant germplasms: 96P51PSI (P51), Z57NO2 (NO2), and 96P55PSI (P55).