Patterns of gas exchange, photosynthate allocation, and root growth during a root growth capacity test

1992 ◽  
Vol 22 (2) ◽  
pp. 248-254 ◽  
Author(s):  
B. Thompson ◽  
P. Puttonen
Keyword(s):  
Gas Exchange ◽  
Root Growth ◽  
Norway Spruce ◽  
Scots Pine ◽  
Carbon Allocation ◽  
Leaf Conductance ◽  
Growth Capacity ◽  
Root Growth Capacity ◽  
Tracer Techniques ◽  
Net Assimilation

Shoot and root growth, net assimilation, leaf conductance and transpiration rates, and carbon allocation were measured on 1.5-year-old Scots pine (Pinussylvestris L.) and Norway spruce (Piceaabies (L.) Karst.) seedlings during a 28-day root growth capacity test. The aim was to determine whether current rates of assimilation, carbon allocation, or shoot growth were related to root growth during the test. Carbon allocation was determined using 14C tracer techniques by exposing the seedlings to, 14CO2 for 24 h, while gas exchange was measured with a LI-COR 6200 meter seven times during the 28-day test. Both species broke bud and displayed substantial root growth. However, the species displayed very different gas exchange and allocation patterns during the test period. In Scots pine, assimilation and leaf conductance increased to a peak at 14–21 days and then began to decrease. Norway spruce showed almost constant and low net assimilation rates and leaf conductance. In both species, the 14C fraction transported to the root increased throughout the 28-day test. Correlations between gas exchange and 14C allocation were insignificant. The correlation between 14C accumulation in roots and increase in number of new roots was significant starting on day 14 in pine and day 23 in spruce.

Here comes the flood! Stress effects of continuous and interval waterlogging periods during the growing season on Scots pine saplings

2020 ◽  
Vol 40 (7) ◽  
pp. 869-885 ◽  
Author(s):  
Timo Domisch ◽  
Ji Qian ◽  
Izabela Sondej ◽  
Françoise Martz ◽  
Tarja Lehto ◽  
...  
Keyword(s):  
Root Growth ◽  
Scots Pine ◽  
Survival Probability ◽  
Electrical Impedance ◽  
Shoot Growth ◽  
Carbon Allocation ◽  
Growing Season ◽  
Hydraulic Conductance ◽  
Extreme Weather Events ◽  
Short Term

Abstract Future climate scenarios for the boreal zone project increasing temperatures and precipitation, as well as extreme weather events such as heavy rain during the growing season. This can result in more frequent short-term waterlogging (WL) leading to unfavorable conditions for tree roots. In addition, it is decisive whether short-term WL periods during the growing season occur continuously or periodically. We assessed the effects of short-termed WL on 4-year-old Scots pine (Pinus sylvestris L.) saplings after shoot elongation started. Waterlogging (WL) lasted either continuously for 2.5 weeks (ContWL) or noncontinuously for 5 weeks, consisting of three repeated 1-week-interval WL periods (IntWL). Both treatments resulted in the same duration of soil anoxia. We studied soil gases, root and shoot growth and physiology, and root survival probability and longevity during the experiment. In the final harvest, we determined shoot and root biomass and hydraulic conductance and electrical impedance spectra of the root systems. Soil CO2 and CH4 concentrations increased immediately after WL onset and O2 decreased until anoxia. Waterlogging decreased fine root survival probability, but there was no difference between WL treatments. Shoot growth suffered more from ContWL and root growth more from IntWL. Needle concentrations of pinitol increased in the WL saplings, indicating stress. No WL effects were observed in photosynthesis and chlorophyll fluorescence. Increased starch concentration in needles by WL may be due to damaged roots and thus a missing belowground sink. Electrical impedance indicated suffering of WL saplings, although root hydraulic conductance did not differ between the treatments. Oxidative stress of short-term and interval WL can have long-lasting effects on shoot and root growth and the physiology of Scots pine. We conclude that even short-term WL during the growing season is a stress factor, which will probably increase in the future and can affect carbon allocation and dynamics in boreal forests.

Changes in drought resistance and root growth capacity of container seedlings in response to nursery drought, nitrogen, and potassium treatments

1992 ◽  
Vol 22 (5) ◽  
pp. 740-749 ◽  
Author(s):  
R. van den Driessche
Keyword(s):  
Drought Stress ◽  
Root Growth ◽  
Drought Resistance ◽  
Lodgepole Pine ◽  
Dry Weight ◽  
White Spruce ◽  
Douglas Fir ◽  
Growth Capacity ◽  
Root Growth Capacity ◽  
N Treatment

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), lodgepole pine (Pinuscontorta Dougl.), and white spruce (Piceaglauca (Moench) Voss) seedlings, each represented by two seed lots, were grown in Styroblock containers in a greenhouse and plastic shelter house from February 1989 to January 1990. The seedlings were exposed to two nitrogen (N) treatments and three potassium (K) treatments arranged factorially within three drought treatments. After winter storage, seedlings from a complete set of treatments were planted into hygric, mesic, and xeric sand beds during 12–14 March. Increasing nursery drought stress increased survival of Douglas-fir and lodgepole pine after planting, and high N treatment level increased survival of lodgepole pine and white spruce. Under xeric conditions, combined nursery drought and high N treatments increased survival of lodgepole pine by 33%, indicating the importance of nursery cultural regime for stock quality. Increase in nursery drought decreased seedling size relatively little, but increase in N increased seedling size one season after planting. A positive relationship between shoot/root ratio and survival in lodgepole pine and white spruce indicated that increase in N increased both shoot growth and drought resistance over the N range investigated. Only Douglas-fir showed an interaction between drought and N treatment and a small response in both survival and dry weight to K. Root growth capacity, measured at the time of planting, showed an approximate doubling in all species due to high N treatment, and was also increased in white spruce by drought stress. Survival and root growth capacity were poorly correlated, but dry-weight growth in sand beds was well correlated with root growth capacity. Shoot dry weight and percent N in shoots measured after nursery growth were correlated with root growth capacity. Manipulation of root growth capacity by changing nursery treatment was apparently possible without altering resistance to drought stress after planting.

Early growth of planted spruce

1984 ◽  
Vol 14 (5) ◽  
pp. 644-651 ◽  
Author(s):  
A. N. Burdett ◽  
L. J. Herring ◽  
C. F. Thompson
Keyword(s):  
Root Growth ◽  
Shoot Growth ◽  
Slow Release ◽  
Unit Length ◽  
White Spruce ◽  
Early Growth ◽  
Height Growth ◽  
Needle Length ◽  
Growth Capacity ◽  
Root Growth Capacity

Observations were made on the growth of white spruce (Piceaglauca (Moench) Voss) and Engelmann spruce (P. engelmanni Parry), each planted at a single location in the interior of British Columbia. In both species bareroot stock (either 2 + 0 seedlings or 2 + 1 transplants) with a low root growth capacity made only limited height growth during the first two seasons after planting. In the first season, many short stem units were formed, whereas in the second season, stem units were much longer but many fewer. The length of needles formed after planting by the bareroot trees was, in the first season, only about half that of needles formed the previous year in the nursery. Needle length increased slightly in the 2nd year. Container-grown trees (1 + 0 seedlings from 336-mL containers), which had a high root growth capacity, made relatively good height growth in the first season when they formed long needles and stem units. Height growth by these seedlings was much less in the second season, however, as were needle length and stem unit number, but not stem unit length. Application of slow release N,P, and K fertilizer at planting improved shoot growth by bareroot trees more in the second season than the first. In contrast, the container-grown stock made a large shoot growth response to fertilization in both the first and the second seasons. The results are consistent with the hypothesis that, as root establishment proceeds, shoot growth tends to be limited by the supply, first of water, then of mineral nutrients. This implies that the early growth of planted spruce can be maximized by using stock with a high root growth capacity, or other adaptations to drought, and applying slow release fertilizer at planting. Observations on the white spruce revealed an acceleration in shoot growth by both stock types during the third season. This followed the establishment, by the end of the second season, of root systems several metres in diameter. A large difference in height: diameter ratio, observed at the time of planting, between the container-grown and bareroot white spruce disappeared entirely in the course of the first three growing seasons.

Understanding root growth capacity: theoretical considerations in assessing planting stock quality by means of root growth tests

1987 ◽  
Vol 17 (8) ◽  
pp. 768-775 ◽  
Author(s):  
A. N. Burdett
Keyword(s):  
Root Growth ◽  
Cold Hardiness ◽  
Quantitative Relationship ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Growth Capacity ◽  
Root Growth Capacity ◽  
Planting Stock Quality ◽  
Field Evidence ◽  
Stock Quality

Laboratory assays for measuring the root growth capacity (RGC) of forest tree seedlings were first developed in the belief that root extension immediately after planting is a major determinant of establishment success. An assumption underlying the development of these tests was that root growth under standardized conditions in the laboratory is indicative of root growth under the generally quite different and often highly variable conditions in the field. Evidence in support of this assumption is slight. Recently, it has been proposed that RGC affects seedling performance, not directly, but by virtue of a correlation with cold hardiness or other types of stress resistance that directly affect performance. For this hypothesis, also, the evidence is slight. There is a need for a clearer understanding of the relationship between RGC and seedling establishment to decide how best to measure and interpret RGC as a gauge of stock quality. This is illustrated by a discussion of the optimum conditions for measuring RGC and of the quantitative relationship between RGC and early performance of planted stock.

Survival and growth of four amabilis fir stock types on Vancouver Island

1991 ◽  
Vol 67 (2) ◽  
pp. 147-154 ◽  
Author(s):  
F. T. Pendl ◽  
B. N. D'Anjou
Keyword(s):  
Root Growth ◽  
Lateral Roots ◽  
Survival Rates ◽  
Field Performance ◽  
Vancouver Island ◽  
Growth Capacity ◽  
Root Growth Capacity ◽  
Stock Type ◽  
Stock Types ◽  
Initial Root

Four stock types of amabilis fir (Abies amabilis) planted on Vancouver Island were compared for root growth capacity and field performance. Initial root growth capacity ratings and field performance of the stock types after five years differed significantly. Ranking the stock types by decreasing survival, stem height and diameter: 1 + 1 PBR 211 (89.4%, 78 cm, 15.7 mm), 1 + 0 PSB 313 (79.7%, 73 cm, 13.8 mm), 1 + 0 PSB 211 (76.8%, 66 cm, 12.9 mm) and 2 + 0 BR (58.9%, 59 cm, 11.0 mm). Given current nursery and planting costs and survival rates, the 1 + 0 PSB 313 and 211 are least expensive reforestation options, the 2 + 0 BR and 1 + 1 PBR 211 the most expensive. Root form of samples of each stock type lack well developed tap and lateral roots with root spiralling evident in the styroblock stock. Key words: Amabilis fir, stock types, bareroot, styroblock plugs

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