## 4 Discussion  
Impact of Drought Stress on Seed Germination and Physiological Characteristics of Sophora vicitiglia  
Drought represents a significant environmental challenge for plants, particularly in karst landscapes, affecting various aspects of plant life including seed germination, growth, and physiological processes [30]. Seed germination, a vital and sensitive phase in the life cycle of plants, is particularly susceptible to external factors, with drought stress being a major inhibitory factor [24]. The primary mechanism through which drought influences seed germination is osmotic stress, which results in decreased germination rates, delayed germination peak, and inhibited growth of both the embryo and radicle [24; 25]. The \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Treatment**} & \multirow{2}{*}{**GP**} & \multirow{2}{*}{**GR**} & \multirow{2}{*}{**GI**} & \multirow{2}{*}{**MDA**} & \multirow{2}{*}{**SOD**} & \multirow{2}{*}{**Pro**} & \multirow{2}{*}{**CAT**} & \multirow{2}{*}{**POD**} & \multirow{2}{*}{**Function**} & \multirow{2}{*}{**Rank**} \\  & & & & & & & & & & \\ \hline CK & 0.375 & 0.533 & 0.350 & 0.553 & 0.542 & 0.455 & 0.440 & 0.602 & 0.481 & 9 \\ A10 & 0.500 & 0.472 & 0.594 & 0.456 & 0.312 & 0.545 & 0.521 & 0.397 & 0.475 & 10 \\ A50 & 0.565 & 0.625 & 0.542 & 0.466 & 0.574 & 0.301 & 0.562 & 0.544 & 0.522 & 4 \\ A100 & 0.607 & 0.656 & 0.608 & 0.408 & 0.416 & 0.407 & 0.586 & 0.374 & 0.508 & 6 \\ A200 & 0.538 & 0.529 & 0.561 & 0.406 & 0.516 & 0.412 & 0.433 & 0.364 & 0.470 & 11 \\ P5 & 0.583 & 0.596 & 0.373 & 0.532 & 0.336 & 0.437 & 0.351 & 0.493 & 0.463 & 12 \\ P5A10 & 0.361 & 0.417 & 0.539 & 0.569 & 0.542 & 0.621 & 0.505 & 0.471 & 0.503 & 8 \\ P5A50 & 0.584 & 0.653 & 0.616 & 0.632 & 0.566 & 0.493 & 0.503 & 0.429 & 0.560 & 1 \\ P5A100 & 0.417 & 0.501 & 0.737 & 0.440 & 0.463 & 0.485 & 0.534 & 0.462 & 0.505 & 7 \\ P5A200 & 0.344 & 0.375 & 0.350 & 0.409 & 0.563 & 0.531 & 0.442 & 0.622 & 0.455 & 13 \\ P20 & 0.375 & 0.501 & 0.547 & 0.366 & 0.463 & 0.338 & 0.450 & 0.395 & 0.429 & 14 \\ P20A10 & 0.544 & 0.509 & 0.643 & 0.618 & 0.407 & 0.572 & 0.610 & 0.538 & 0.555 & 2 \\ P20A50 & 0.513 & 0.517 & 0.732 & 0.604 & 0.498 & 0.515 & 0.525 & 0.435 & 0.542 & 3 \\ P20A100 & 0.567 & 0.488 & 0.428 & 0.547 & 0.583 & 0.589 & 0.484 & 0.474 & 0.520 & 5 \\ P20A200 & 0.372 & 0.519 & 0.566 & 0.365 & 0.346 & 0.316 & 0.397 & 0.405 & 0.411 & 15 \\ \hline \end{tabular} Note: CK represents 0 mg.\(\text{L}^{-1}\) ABA and 0% PEG-6000; A10 represents 10 mg.\(\text{L}^{-1}\) ABA; A50 represents 50 mg.\(\text{L}^{-1}\) ABA; A100 represents 100 mg.\(\text{L}^{-1}\) ABA; A200 represents 20 mg.\(\text{L}^{-1}\) ABA; P5 represents 5% PEG-6000; P20 represents 20% PEG-6000.  
\end{table} 
Table 6: Comprehensive evaluation of the effect of exogenous ABA on drought resistance using membership function value. \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{1}{c}{**Variance**} & \multicolumn{1}{c}{**Principal Component 1**} & \multicolumn{1}{c}{**Principal Component 2**} \\ \hline Germination rate (GR) & \(-0.0466\) & \(0.6111\) \\ Germination potential (GP) & \(0.2153\) & \(0.5038\) \\ Germination index (GI) & \(0.1462\) & \(0.5799\) \\ POD activity & \(0.4187\) & \(-0.1250\) \\ SOD activity & \(0.4437\) & \(-0.0175\) \\ CAT activity & \(0.4429\) & \(-0.0589\) \\ MDA content & \(0.4217\) & \(-0.0890\) \\ Pro content & \(0.4288\) & \(-0.0957\) \\ Eigenvalue & \(4.804\) & \(2.331\) \\ Contribution rate (\%) & \(60.05\%\) & \(29.14\%\) \\ Cumulative contribution rate (\%) & \(60.05\%\) & \(89.19\%\) \\ \hline \end{tabular}
\end{table} 
Table 5: Principal component results of seed germination and physiological indices in _Sophora vicitiglia_. findings of [PERSON] et al. (2018) indicate that while low concentrations of PEG can enhance the germination of alfalfa (_Medicago sativa_) seeds, higher concentrations markedly suppress this process [30].