scholarly journals Container Color and Compost Substrate Affect Root Zone Temperature and Growth of “Green Giant” Arborvitae

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 484 ◽  
Author(s):  
Anthony L. Witcher ◽  
Jeremy M. Pickens ◽  
Eugene K. Blythe

Container-grown nursery crops are commonly exposed to root zone stress due to inadequate moisture and supraoptimal root zone temperature (RZT). Compost substrates can improve water and nutrient retention but plant responses can vary due to physical and chemical properties. Dark color containers absorb solar radiation through the container side wall leading to excessive heat buildup in the substrate, yet white containers can reduce RZT. Compost substrates and container color were examined for effects on RZT and growth of “Green Giant” arborvitae (Thuja standishii × plicata “Green Giant”). “Green Giant” arborvitae were transplanted into white or black containers (11.3 L) filled with a pine bark substrate (PB) or PB mixed with compost (C) at two different proportions [PB:C (9:1) and PB:C (7:3)]. White containers reduced maximum RZT by up to 7 °C and RZT remained above 38 °C for only 3% of the time compared to 21% of the time in black containers. Shoot growth increased over 50% in white containers compared to black containers. Compost increased substrate volumetric water content (VWC), increased shoot growth by up to 24%, and reduced total irrigation volume by up to 40%. Utilizing white containers for minimizing RZT and compost-amended substrates to maintain adequate VWC can improve root and shoot growth and overall crop quality while reducing nursery production inputs.

HortScience ◽  
1991 ◽  
Vol 26 (7) ◽  
pp. 870-872 ◽  
Author(s):  
M. Tagliavini ◽  
N.E. Looney

Root and shoot growth of peach seedlings was strongly suppressed when the roots were held at 8 to 10C. Shoot and root dry weights and root volume increased linearly with increasing root-zone temperature (RZT) to 22C. GA3 at 5.7 μm (2 ppm) added to the aerated full nutrient solution reversed the effect of low RZT on shoot elongation but inhibited root growth at all RZTs. Paclobutrazol (PBZ) (6.8 × 10-3μm) (2 ppb) inhibited shoot elongation at all RZTs and shoot dry weight at 16 and 22C. However, PBZ had no effect on root dry weight accumulation at any RZT. The shoot growth-promoting effect of GA3, relative to control plants, disappeared at higher RZTs, but GA3 reversed the growth-inhibiting effect of PBZ at all RZTs. PBZ increased mean root diameter at all RZTs and significantly increased root volume at 22C. These results show that growth of peach seedlings is profoundly influenced by a cool root-zone environment. The plant growth regulator effects suggest that seedling roots play an important role in whole-plant gibberellin physiology. Some possible implications for fruit production are discussed. Chemical names used: gibberellic acid (GA3); β -[(4-chlorophenyl)methyl]- α -(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol(paclobutrazol,PBZ).


2015 ◽  
Vol 21 (3) ◽  
pp. 479-489 ◽  
Author(s):  
S.J. Clarke ◽  
K.J. Lamont ◽  
H.Y. Pan ◽  
L.A. Barry ◽  
A. Hall ◽  
...  

2020 ◽  
Vol 5 (1) ◽  
pp. 317-324
Author(s):  
Kayla Snyder ◽  
Christopher Murray ◽  
Bryon Wolff

AbstractTo address agricultural needs of the future, a better understanding of plastic mulch film effects on soil temperature and moisture is required. The effects of different plant type and mulch combinations were studied over a 3.5-month period to better grasp the consequence of mulch on root zone temperature (RZT) and moisture. Measurements of (RZT) and soil moisture for tomato (Solanum lycopersicum), pepper (Capsicum annuum) and carrot (Daucus carota) grown using polyolefin mulch films (black and white-on-black) were conducted in Ontario using a plot without mulch as a control. Black mulch films used in combination with pepper and carrot plants caused similar RZTs relative to uncovered soil, but black mulch film in combination with tomato plants caused a reduction in RZT relative to soil without mulch that increased as plants grew and provided more shade. White-on-black mulch film used in combination with tomatoes, peppers or carrots led to a reduction in RZT relative to soil without mulch that became greater than the temperature of soil without mulch. This insulative capability was similarly observed for black mulch films used with tomato plants. Apart from white-on-black film used in combination with tomatoes, all mulch film and plant combinations demonstrated an ability to stabilize soil moisture relative to soil without mulch. RZT and soil moisture were generally stabilized with mulch film, but some differences were seen among different plant types.


1987 ◽  
Vol 67 (2) ◽  
pp. 409-415 ◽  
Author(s):  
A. MENKIR ◽  
E. N. LARTER

Based on the results of an earlier paper, 12 inbred lines of corn (Zea mays L.) were evaluated for emergence and seedling growth at three controlled root-zone temperatures (10, 14, and 18 °C). Low root-zone temperatures, 10 and 14 °C, were detrimental to emergence, seedling growth, and root growth of all inbred lines. Differential responses of inbred lines were observed within each temperature regime. The differences in seedling emergence among lines became smaller with increasing root-zone temperature, while the reverse was true for seedling dry weight. Simple correlation coefficients showed a significantly (P = 0.05) negative association between emergence percentage and emergence index (rate). Neither of these two emergence traits was significantly correlated with seedling dry weights. Seedling dry weights were significantly (P = 0.01) and positively associated with root dry weights. Two inbred lines exhibited good tolerance to low root-zone temperatures, viz. CO255 and RB214. A significant and positive correlation existed between emergence percentage at a root-zone temperature of 10 °C and field emergence in test with the same genotypes reported earlier. Selection at a root-zone temperature of 10 °C for a high percentage of seedling emergence, therefore, could be effective in identifying genotypes capable of germinating in cool soils. Furthermore, the significantly (P = 0.01) positive relationship between seedling dry weights at all root-zone temperatures and those from the field test suggest that strains with vigorous seedling growth in the field could be identified using low root-zone temperature regimes.Key words: Zea mays, root-zone temperature, cold tolerance


1986 ◽  
Vol 16 (4) ◽  
pp. 696-700 ◽  
Author(s):  
Chris P. Andersen ◽  
Edward I. Sucoff ◽  
Robert K. Dixon

The influence of root zone temperature on root initiation, root elongation, and soluble sugars in roots and shoots was investigated in a glasshouse using 2-0 red pine (Pinusresinosa Ait.) seedlings lifted from a northern Minnesota nursery. Seedlings were potted in a sandy loam soil and grown in chambers where root systems were maintained at 8, 12, 16, or 20 °C for 27 days; seedling shoots were exposed to ambient glasshouse conditions. Total new root length was positively correlated with soil temperature 14, 20, and 27 days after planting, with significantly more new root growth at 20 °C than at other temperatures. The greatest number of new roots occurred at 16 °C; the least, at 8 °C. Total soluble sugar concentrations in stem tissue decreased slightly as root temperature increased. Sugar concentrations in roots were similar at all temperatures. The results suggest that root elongation is suppressed more than root tip formation when red pine seedlings are exposed to the cool soil temperatures typically found during spring and fall outplanting.


1995 ◽  
Vol 13 (2) ◽  
pp. 82-85
Author(s):  
Lorna C. Wilkins ◽  
William R. Graves ◽  
Alden M. Townsend

Abstract Two experiments were conducted to determine whether genotypes of red maple (Acer rubrum L.) and Freeman maple (A. x freemanii E. Murray) differ in responses to high root-zone temperature. During the first experiment, dry mass of ‘Franksred’, ‘October Glory’, and ‘Schlesinger’ red maple, ‘Indian Summer’ Freeman maple, and selections from Arkansas, Maine, and Wisconsin were similar at 24, 28, and 32C (75, 82, and 90F), but dry mass at 36C (97F) was only 22% of that at 28C (82F). ‘Autumn Flame’, ‘Franksred’, ‘October Glory’, and ‘Schlesinger’ red maple and ‘Indian Summer’ and ‘Jeffersred’ Freeman maple differed in responses to 34C (93F) during the second experiment. Stem length and plant dry mass were higher at 28C (82F) than at 34C (93F) for all cultivars except ‘Autumn Flame’ and ‘Jeffersred’, and the extent to which 34C (93F) decreased the length of the longest third-order root ranged from 50% for ‘Autumn Flame’ to 90% for ‘Indian Summer’. The higher root-zone temperature decreased transpiration by as little as 25% for ‘Jeffersred’ to as much as 89% for ‘Franksred’, and 34C (93F) reduced leaf chlorophyll content of only ‘Indian Summer’ and ‘Jeffersred’. These results indicate that ‘Franksred’ and ‘Indian Summer’ are relatively sensitive while ‘Autumn Flame’, ‘Jeffersred’, and ‘Schlesinger’ are relatively resistant to high root-zone temperature.


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