Effects of Clinorotation on the Enzyme Activities and Morphology of <i>Zea mays</i> Seedlings

Abstract

For sustainable space exploration there is need for torrential food supply. Apart from food in storage, constant production is vital as this could also serve as a source of Oxygen when activated during space expedition. However, the impact of gravity in crop development is significant. This study therefore, investigated the morphological and physiological responses of Maize (Zea mays) seedlings subjected to clinorotation. Agar Agar was used as source of nutrient for the developing seedlings. The Agar was prepared by measuring 1 -1.5 g and made up to 100 ml with tap water. Seeds were collected in the seed bank of the Space-Earth Environment Research Laboratory, Benin City. Three sets of petri dishes were prepared and marked; one for normal surface, one rotated at 90°C and another set for clinorotation. Those for clinorotation were rotated at three different times; with 1, 2, and 3 rpm for 6 hrs respectively. The plumule, radicle and Enzyme activities were measured and analysed after four days. Results showed significant difference in germination parameters as occasioned by microgravity. Where as clinorotation enhanced radicule length (1.8-2.1cm), effect on plumule was minimal (p>0.05). Significant increase in CAT activity in the plumule was reported (7.59mol/sec) in the clinorotated (1rpm) seed compared to the control (2.56mol/sec). MDA activity in both radicle and plumule were higher than that of the control (p<0.05). Microscopic study of the cells was carried out using a binocular microscope (Labo) with a camera and result showed that the normal surface sample cells were arranged concentrically with spaces, while that of clinorotated seeds were arranged concentrically but highly packed with little spaces for the plumule. For the radicle, the normal surface sample cells were scattered within the plant with more spaces, while that of clinorotated were mostly clustered throughout.

Influence of selected plant growth stimulators in enhancing germinability and germination parameters of Zea mays L. under microgravity conditions simulated by a two-dimensional clinostat

“…Before maize seed stimulation with plant growth promoters, the reduced germination parameters observed in the current study when seeds were exposed to microgravity as against the control indicated the perturbations of many biological phenomena due to the effect of altered gravity (De Micco et al, 2013). This is consistent with the work of Orukpe et al (2021) where he explained that microgravity is a major impediment to maize seed germination in most parts of the world. In order to ameliorate this effect, the researchers discovered that exposing seeds to growth stimulants or seed pre-treatment improved seed germination rate, seedling vigor, and growth statistics, reducing the effect of microgravity on maize seed germinability (p>0.05).…”

“…In a previous report, microgravitational effect on maize seeds under 0.5, 1.0, and 2.0 rpm clinorotation significantly decreased maize seed growth capacities and germinability (Orukpe at al., 2021). The maize germinants' enzyme status was also significantly impacted.…”

“…Preparation followed standard methods as used by Orukpe et al (2021). The Agar was prepared by weighing 1.5g in 100 ml of distilled water.…”

“…The Earth's gravity, which exerts a force of "1 g," has resulted in the formation of plants. During space travel, one of the greatest effects on plants is the influence of gravity (Levine, 2010;Vandenbrink et al, 2014;Braun et al, 2018;Kiss et al, 2019;Orukpe et al, 2021). This ubiquitous force influences plant development, productivity, and morphology at all levels, from the molecular to the whole plant (Vandenbrink et al, 2014).…”