Weight is a key factor in the physiological quality of Parapiptadenia rigida seeds

Abstract

The objective of this work was to evaluate hygroscopicity modification of Eucalyptus dunnii, E. saligna and Corymbia maculata wood due to termites attack. Using samples measuring 20 x 20 x 150 mm³ (tangential x radial x longitudinal) the equilibrium moisture content (MCE), linear contractions of the tangential and radial planes (βT e βR), contraction anisotropy (CAβ), water absorption (AA) and water absorption rate (TAA) of healthy and deteriorated wood by Nasutitermes termites were evaluated. It was verified that the termite attack caused increase in TUE and reduction in βT. However, βR and CAβ presented different behaviors, varying among the different species. AA and TAA presented higher water absorption intensity in the first hours of immersion, being higher in the control group in comparison with the deteriorated samples. Possibly the variations in the parameters related to the wood hygroscopicity of the studied species are correlated to the increase of porosity and deterioration mainly of cellulose and hemicelluloses, directly affecting the wood's ability to absorb and lose moisture, compromising the material quality.

Morphological integration between seeds and seedlings ofHymenaea courbaril

“…The correlation lines also differed between the populations, while population I had an almost steady value, with a low correlation index, population II had a positive correlation and substantially higher coefficient of determination ( Figure 4). Previous analysis indicated that greater seed weight promoted faster germination rates to Parapiptadenia rigida, another member of the Fabaceae family [7]. When considering the populations isolated, to population I, the relationship between seed weight and time required for germination is positive.…”

“…Thus, the great genetic diversity of these species [38], [39] is generally pointed out as the mean cause. However, seed growth is also influenced by environmental cues [7], [9], [40] such as edaphoclimatic differences [9] and ecologic interactions [4].…”

“…Some studies have shown that biometrics of seeds could be used as an indirect parameter to propitiate grater and homogenous germination, and also favoring the germination of the embryo resulting in the most vigorous seedlings [1], [4], [6]. In general, seeds displaying larger size or density are potentially more vigorous because they usually have more reserves and they present well-formed embryos [7].…”

“…Seed mass is a feature of great importance because it is linked to recruitment via germination, seedling establishment, and offspring, [7]. There is some uncertainty about the relationship between seed weight and/or size in seedling vigor [7].…”

“…Seed mass is a feature of great importance because it is linked to recruitment via germination, seedling establishment, and offspring, [7]. There is some uncertainty about the relationship between seed weight and/or size in seedling vigor [7]. While crop science has been shown that, to economically relevant species, seed size is an appropriate parameter to measure seedling quality and vigor, in forestry species case, and especially from tropical countries [4], this is not extensively explored [8], [9].…”