Effects of acid and aluminum stress on seed germination and physiological characteristics of seedling growth in Sophora davidii

Abstract

Sophora davidii , a vital forage species, predominantly thrives in the subtropical karst mountains of Southwest China. Its resilience to poor soil conditions and arid environments renders it an ideal pioneer species for ecological restoration in these regions. This study investigates the influence of acidic, aluminum-rich local soil on the germination and seedling growth physiology of S. davidii . Experiments were conducted under varying degrees of acidity and aluminum stress, employing three pH levels (3.5 to 5.5) and four aluminum concentrations (0.5 to 2.0 mmol·L −1 ). The results showed that germination rate, germination index, and vigor index of S. davidii seeds were decreased but not significantly under slightly acidic conditions (pH 4.5–5.5), while strong acid (pH = 3.5) significantly inhibited the germination rate, germination index, and vigor index of white spurge seeds compared with the control group. Aluminum stress (≥0.5 mmol·L −1 ) significantly inhibited the germination rate, germination index, and vigor index of S. davidii seed. Moreover, the seedlings’ root systems were sensitive to the changes of aluminum concentration, evident from significant root growth inhibition, characterized by root shortening and color deepening. Notably, under aluminum stress (pH = 4.3), the levels of malondialdehyde and proline in S. davidii escalated with increasing aluminum concentration, while antioxidant enzyme activities demonstrated an initial increase followed by a decline. The study underscores the pivotal role of cellular osmoregulatory substances and protective enzymes in combating aluminum toxicity in S. davidii , a key factor exacerbating growth inhibition in acidic environments. These findings offer preliminary theoretical insights for the practical agricultural utilization of S. davidii in challenging soil conditions.

Synergistic effects of exogenous IAA and melatonin on seed priming and physiological biochemistry of three desert plants in saline-alkali soil

“…Germination was determined by using seed breakthrough as the criterion for germination; germination was determined by using (total number of seeds germinated before harvest/number of seeds tested) × 100%; Germination potential was determined using (total number of seeds germinated within 5 d/number of seeds supplied) × 100%; Ten seedlings were taken after 21 d for the determination of morphological indicators. 24 Fresh weight: weighed accurately using a one-thousandth electronic balance. Dry weight: single seedlings from each group were killed in an oven at 105°C for 30 min and then transferred to 80°C for drying to constant weight, and the dry weight of roots and seedlings was accurately weighed using a one-thousandth balance and recorded.…”