What are the effects of nitrogen deficiency on growth components of lettuce?

Abstract

Relationships between nitrogen (N) content and growth are routinely measured in plants. This study determined the effects of N on the separate morphological and physiological components of plant growth, to assess how Nlimited growth is effected through these components. Lettuce (Lactuca sativa) plants were grown hydroponically under contrasting N-supply regimes, with the external N supply either maintained continuously throughout the period of study, or withdrawn for up to 14 d. Richards' growth functions, selected using an objective curve-fitting technique, accounted for 99n0 and 99n1% of the variation in plant dry weight for control and N-limited plants respectively. Sublinear relationships occurred between N and relative growth rates under restricted N-supply conditions, consistent with previous observations. There were effects of treatment on morphological and physiological components of growth. Leaf weight ratio increased over time in control plants and decreased in Nlimited plants. Shoot : root ratio followed a similar pattern. On a whole-plant basis, assimilation of carbon decreased in N-limited plants, a response paralleled by differences in stomatal conductance between treatments. Changes in C assimilation, expressed as a function of stomatal conductance to water vapour, suggest that the effects of N limitation on growth did not result directly from a lack of photosynthetic enzymes. Relationships between plant N content and components of growth will depend on the availability of different N pools for remobilization and use within the plant.

Effect of nitrogen supply on growth and photosynthesis of sunflower plants grown in the greenhouse

“…There are contradictory data in the literature about the effect of nitrogen on gs. Lower rates of gs in low N-grown plants have been reported [22,23]. On the other hand, opposite effect [24] or no effect [12,25] by nitrogen are also reported.…”

Effect of Nitrogen Fertilization on Growth and Photosynthetic Nitrogen use Efficiency in Tobacco (Nicotiana tabacum L.)

“…However, there are contradictory data in the literature about the effect of nitrogen on g s . Lower rates of g s in low N-grown plants have been reported [10,21]. On the other hand, opposite effect or no effect [22] by nitrogen are also reported.…”

Effects of drought stress and N supply on the growth, biomass partitioning and water-use efficiency of Sophora davidii seedlings

“…In general, plants are often faced with a trade-off for allocating protein towards photosynthesis or to nutrient uptake (Patterson et al, 1997). Broadley et al (2000), furthermore, explained that plants often use N primarily for the production and maintenance of leaves in order to maximize carbon fixation. Increased leaf percentages and reduced fine root percentages with increase of N supply in this study also supports this conclusion.…”