Crescimento e ecofisiologia de pitaias cultivadas em vasos submetidas a diferentes doses de k e ca

Abstract

It is obvious that the national agriculture has been changing rapidly in recent years. Given this, the culture of Dragon fruit has been shown in a viable alternative to farmers in the Northeast region. How do limiting factors include: the incipient information regarding mineral plant nutrition combined with growth data of culture (phenology). Developed a work in order to evaluate the influence of potassium and calcium in the development of white pitaya and its relationship to gas exchange and mineral characterization of their cladodes in the State of Ceará. The statistical design used was randomized blocks, in factorial 4 x 4, with 16 treatments and three replicates. The treatments were composed of potassium doses, with four levels (0, 125, 250 and 375 mg K dm-3) and doses of calcium, with four levels (0, 53, 106 and 159 mg Ca dm-3). The evaluations were conducted at two different times: 120 and 270 days for biometrics and 150 and 240 days for the evaluations of gas exchange. Photosynthetic pigments and chemical characterization of cladodes were carried out to 270 days. For the morphological characters, the nutritional interaction 375:53 mg dm-3 (K:CaO) was the one that stood out in the first 120 days, in the final step, the interaction that stood out was 250:159 mg dm-3 (K:Ca). Net photosynthesis was greater in the 125 mg dm-3 dose and 0 mg Ca dm-3. The photosynthetic pigments have excelled in the same doses of the 270-day assessment of biometrics. For the environmental conditions in which the test was conducted, the 250 and 159 mg dm-3 (K:Ca) doses were the ones that stood out. At the same time, in another work, the objective of evaluating the biometrics of the species Hylocereus undatus, sp. and Hylocereus setaceus in response to five doses of potassium, as well as to measure the content of this element in the tissues of these species of Cactus, grown in cladodes not rooted in pots of 11 dm-3. Initial growth was evaluated for each species separately (number of cladodes – NCL; sum of length of cladodes – SCC; diameter of cladodes – DCL; thickness of cladodes – ECL), as a function of time and doses of K in the form of chloride. In addition to the number of crow (NAU), length of root system (CSR), width of root system (LSR), fresh mass from the shoot (MFA) and aerial dry mass (MSA), comparing the species and those doses of K. For evaluation of initial growth variables, experimental design was used in DBC with four repetitions in subdivided plots, using as factors the doses of K (0, 80, 160, 240 and 320 mg dm-3) and time (180 and 270 days). About the other variables in the design was randomized blocks in factorial scheme 3x5, using as the species and referred to doses of K with factors. Among the initial growth measurements, there was an increase in values in relation to time, regardless of species. In the destructive measurements, the Hylocereus undatus presented the highest values being of 29.1 cm for root length, 16.2 cm for root width, 218.3 g for fresh pasta from aerial part and 36.8 g dry pasta aerial part. The biggest accumulation of K in the tissues of species, occurred in the Hylocereus setaceus, with values of 57.9 g kg-1 for cladodes and 5.8 g kg-1 in the roots. Therefore, under the conditions of the realization of research, in protected environment, the species that stood out morphologically was the H. undatus and chemically was the H. setaceus, being the intermediate Hylocereus sp. in all evaluations.