Abstract
A research work was carried out at the Bangladesh Agricultural University, Mymensingh during October 1996 to March 1999 to study the effect of different soil moisture regimes on the physio-morphological features of 10 accessions of chilli Capsicum annum L. These were C-0277, C-0297, BM-1, C-0100, BM-2, C-0265, C-0272, C-0275, BM- 3 and C-0271. Three experiments were carried out in pots at the glass-house and one in the field. There were 3 factors in each experiment: water treatments (4-6 W), growth stages (3-6 S) and chilli accessions (2V-10V). The present investigation was mainly made on growth features, anatomical features and stomatal counting. The growth parameters were, the number of leaves/plant, leaf area, plant height, number of internodes, canopy diameter, root length, root volume, number of fruits/plant, fruit length and diameter, individual fruit weight, fruit yield/plant, dry weight of leaf, stem, root, fruit etc. Comparative anatomical features of root, stem and leaf, as well as, counting of stomata (open and closed) were also studied in the water stress tolerant and susceptible accessions of chilli.
As the single effect or combined effects of W x S x V, the results of any growth parameter or all the parameters showed significant differences. On the basis of total dry matter contents, supported by the results of other growth parameters, the accessions C-0277 and C-0272 came out as water stress tolerant and water susceptible accessions of chilli. Anatomically chilli resembled a typical woody dicotyledonous herb in its primary and secondary structures. In the root, stem and leaf, the tracheary elements were more developed and organized in the water stress tolerant accession of C-0277 than those in the water susceptible accession, C-0272. The xylem vessels were larger and thicker, the ray parenchymatous cells were thicker, epidermal cells were smaller and thicker, and spongy parenchymatous cells (leaf) were larger with bigger air spaces in the water stress tolerant accession than those in the water susceptible one. The number of open and closed stomata on both ventral and dorsal surfaces of the leaf in water stress tolerant accession (C-0277) was more than that in the susceptible accession of C-0272. Under optimal level of soil moisture, the percentage of open stomata was more in both the water tolerant and susceptible accessions than that of excess or deficit soil moisture regimes.