Hi I need to know what nutritional disbalance could make that aerial parts of pineapples plants growth so much than the radicular parts and with a huge acumulation of water on the leafs.
Thanks
When plants are overly rich in Nitrogen, top growth can be favored at the expense of radicle growth. In addition Nitrogen rich and unbalanced when compared to a more balanced nutrition the plants will tend to be watery and can be more susceptible to sucking insects and some diseases.
The ideal tissue contents can be found in the scientific literature. Take at least 20 leaf samples in areas of normal and excess top growth to compare. Have them analyzed by spectral analysis of dry matter for both the macro and micro nutrients. Compare your test values to the literature values. Look for deficiencies and excesses and then adjust your nutrition program according.
After making nutritional adjustment re analyze the tissue samples for their contents.
To supplement your tissue analysis also make an analysis of your soil contents to get a comprehensive view.
Imbalance between radicular and aerial parts of pineapple could only happen , when proportion of nitrogen to other nutrients like phosphorous and potassium is proportionately higher . But , best course would be to get leaf analysis done , and interpret the leaf analysis results on the basis of nutrient ration , instead of individual nutrient concentration . DRIS concept is one such concept , which can address such issues, besides giving an idea about the order in which different nutrients are causing such imabalnces. Here is a PDF enclosed to spell out the procedure to be adopted for collection of leaf samples as under:
‘D’-leaves from 10 different plants were collected at 30 days interval from one representative pineapple field . The basal 4 cm portion from each of the collected leaf samples to be separated,packed in perforated polythene bags, and brought to the laboratory for onward analysis.
Thornley (1972) has proposed a simple model which is widely used . In the model, growth is dependent on the supply of carbon from the shoot and nitrogen from the root, i.e. the flux of carbon from shoot to roots (phloem transport) and that of nitrogen from roots to shoot (xylem transport). The fluxes are dependent on the concentration gradients of carbon and nitrogen between these two compartments, shoot and roots. According to Thornley's model, conditions which lead to an increase in carbon concentration should, therefore, lead to an increase in biomass partitioning towards the roots, whereas an increase in nitrogen concentration should favour biomass partitioning towards the shoot. In principle, the model is also considered suitable to take into account the effects of various environmental factors including mineral nutrients on the shootroot ratio.
Nice response Dr Malhotra in the context of on-going discussion , appreciate your excellent inputs. Let me put up my another response :
In most plants, nitrate reductase activity is found in both shoots and roots; however, the proportion of nitrate assimilation occurring in roots vs. shoots varies among species. Many woody species exhibit significant leaf nitrate reductase activity, contrary to the previous conclusion that most nitrate is reduced in the roots of woody plants (Pate, 1980). Leaf NR activity in woody plants varies widely, with activities as high as 11·9 µmol NO2 g f. wt–1 h–1 reported in Trema guineensis (Smirnoff et al., 1984). However, in the Vaccinium species that have been studied, leaf NR activity is very low or non‐detectable (Smirnoff et al., 1984; Merhaut, 1993; Claussen and Lenz, 1999). Additionally, root NR activity in Vaccinium is similar to or lower than root NR activity found in most other woody plants (Townsend, 1970; Merhaut, 1993; Claussen and Lenz, 1999). Thus, the overall nitrate reduction capacity in Vaccinium is significantly lower than in other woody plants. This may result in insufficient uptake and reduction of nitrate (Spiers, 1978), leading to slower growth rates (Claussen and Lenz, 1999), and becoming a limiting factor for Vaccinium growth under nitrate conditions (Korcak, 1988). So , it is the preferential vascular connection between aerial parts shoots and underground roots , without any preferential response to nutrients , but which nutrients are influenced by such lack of synchrony between roots and shoots , will decide the particular nutritional disorder...
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